Introduce deprecation of companion objects nested classes

Introdude deprecation as per KT-21515. Warning is reported on type
usage, that soon will became invisible. Quickfix by adding explicit
import is added.

Idea behind implementation is to mark scopes that are deprecated (see
ClassResolutionScopesSupport).

Then, during walk along hierarchy of scopes, look at deprecation status
of the scope that has provided this classifier.
Note that we also have to check if there are *some* non-deprecated
visibility paths (because we can see classifier by two paths, e.g. if
we've added explicit import) -- then this type reference shouldn't be
treated as deprecated.

compiler/testData/diagnostics/tests/objects/kt21515/annotationConstructor.kt

@@ -0,0 +1,13 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+
+open class Base {
+    companion object {
+        annotation class Foo
+    }
+}
+
+class Derived : Base() {
+
+    @<!DEPRECATED_ACCESS_BY_SHORT_NAME!>Foo<!>
+    fun foo() = 42
+}

compiler/testData/diagnostics/tests/objects/kt21515/annotationConstructor.txt

@@ -0,0 +1,30 @@
+package
+
+public open class Base {
+    public constructor Base()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final annotation class Foo : kotlin.Annotation {
+            public constructor Foo()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public final class Derived : Base {
+    public constructor Derived()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    @Base.Companion.Foo public final fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferenceComplexCasesWithImportsOld.kt

@@ -0,0 +1,74 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+
+import A.Base.Companion.FromABaseCompanion
+import B.Base.Companion.FromBBaseCompanion
+import C.Base.Companion.FromCBaseCompanion
+import D.Base.Companion.FromDBaseCompanion
+
+// ===== Case 1: LHS is a class
+//
+object A {
+    open class Base {
+        companion object {
+            class FromABaseCompanion {
+                fun foo() = 42
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = FromABaseCompanion::foo
+    }
+}
+
+// ===== Case 2: LHS is a class with companion object, function comes from class
+
+object B {
+    open class Base {
+        companion object {
+            class FromBBaseCompanion {
+                fun foo() = 42
+
+                companion object {}
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = FromBBaseCompanion::foo
+    }
+}
+
+// ==== Case 3: LHS is a class with companion object, function comes from companion
+
+object C {
+    open class Base {
+        companion object {
+            class FromCBaseCompanion {
+                companion object {
+                    fun foo() = 42
+                }
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = FromCBaseCompanion::<!UNRESOLVED_REFERENCE!>foo<!>
+    }
+}
+
+// ==== Case 4: LHS is an object
+
+object D {
+    open class Base {
+        companion object {
+            object FromDBaseCompanion {
+                fun foo() = 42
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = FromDBaseCompanion::foo
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferenceComplexCasesWithImportsOld.txt

@@ -0,0 +1,163 @@
+package
+
+public object A {
+    private constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromABaseCompanion {
+                public constructor FromABaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+    }
+
+    public final class Derived : A.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction1<A.Base.Companion.FromABaseCompanion, kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object B {
+    private constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBBaseCompanion {
+                public constructor FromBBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public companion object Companion {
+                    private constructor Companion()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    public final class Derived : B.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction1<B.Base.Companion.FromBBaseCompanion, kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object C {
+    private constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCBaseCompanion {
+                public constructor FromCBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public companion object Companion {
+                    private constructor Companion()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public final fun foo(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    public final class Derived : C.Base {
+        public constructor Derived()
+        public final val a: [ERROR : Type for FromCBaseCompanion::foo]
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object D {
+    private constructor D()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public object FromDBaseCompanion {
+                private constructor FromDBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+    }
+
+    public final class Derived : D.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction0<kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesComplexCasesWithQualificationOld.kt

@@ -0,0 +1,69 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+
+// ===== Case 1: LHS is a class
+//
+object A {
+    open class Base {
+        companion object {
+            class FromBaseCompanion {
+                fun foo() = 42
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = A.Base.Companion.FromBaseCompanion::foo
+    }
+}
+
+// ===== Case 2: LHS is a class with companion object, function comes from class
+
+object B {
+    open class Base {
+        companion object {
+            class FromBaseCompanion {
+                fun foo() = 42
+
+                companion object {}
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = B.Base.Companion.FromBaseCompanion::foo
+    }
+}
+
+// ==== Case 3: LHS is a class with companion object, function comes from companion
+
+object C {
+    open class Base {
+        companion object {
+            class FromBaseCompanion {
+                companion object {
+                    fun foo() = 42
+                }
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = C.Base.Companion.FromBaseCompanion::<!UNRESOLVED_REFERENCE!>foo<!>
+    }
+}
+
+// ==== Case 4: LHS is an object
+
+object D {
+    open class Base {
+        companion object {
+            object FromBaseCompanion {
+                fun foo() = 42
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = D.Base.Companion.FromBaseCompanion::foo
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesComplexCasesWithQualificationOld.txt

@@ -0,0 +1,163 @@
+package
+
+public object A {
+    private constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBaseCompanion {
+                public constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+    }
+
+    public final class Derived : A.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction1<A.Base.Companion.FromBaseCompanion, kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object B {
+    private constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBaseCompanion {
+                public constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public companion object Companion {
+                    private constructor Companion()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    public final class Derived : B.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction1<B.Base.Companion.FromBaseCompanion, kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object C {
+    private constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBaseCompanion {
+                public constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public companion object Companion {
+                    private constructor Companion()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public final fun foo(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    public final class Derived : C.Base {
+        public constructor Derived()
+        public final val a: [ERROR : Type for C.Base.Companion.FromBaseCompanion::foo]
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object D {
+    private constructor D()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public object FromBaseCompanion {
+                private constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+    }
+
+    public final class Derived : D.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction0<kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesNew.kt

@@ -0,0 +1,142 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// See KT-21515 for a class diagram and details
+
+// class is to prevent accidental short-name import
+class O {
+    open class Alpha {
+        open fun foo() = 42
+
+        class FromAlpha {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionAlpha {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class Beta : Alpha() {
+        override fun foo() = 42
+
+        class FromBeta {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionBeta {
+                fun foo() = 42
+            }
+        }
+    }
+
+
+    open class A {
+        open fun foo() = 42
+
+        class FromA {
+            fun foo() = 42
+        }
+
+        companion object : Beta() {
+            class FromCompanionA {
+                fun foo() = 42
+            }
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open fun foo() = 42
+
+        class FromFarAway {
+            fun foo() = 42
+        }
+
+    }
+
+    open class Gamma {
+        open fun foo() = 42
+
+        class FromGamma {
+            fun foo() = 42
+        }
+
+        companion object : FarAway() {
+            class FromCompanionGamma {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class B : A() {
+        override fun foo() = 42
+
+        class FromB {
+            fun foo() = 42
+        }
+
+        companion object : Gamma() {
+            override fun foo() = 42
+
+            class FromCompanionB {
+                fun foo() = 42
+            }
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open fun foo() = 42
+    class FromDelta {
+        fun foo() = 42
+    }
+}
+
+class C : O.B() {
+    override fun foo() = 42
+
+    companion object : Delta() {
+        class FromCompanionC {
+            fun foo() = 42
+        }
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = FromA::foo
+    val d = FromB::foo
+
+    // VISIBLE: Classifiers from our own companion
+    val n = FromCompanionC::foo
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = <!UNRESOLVED_REFERENCE!>A<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val b = <!UNRESOLVED_REFERENCE!>A<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = <!UNRESOLVED_REFERENCE!>FromCompanionA<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val f = <!UNRESOLVED_REFERENCE!>FromCompanionB<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = <!UNRESOLVED_REFERENCE!>Alpha<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val h = <!UNRESOLVED_REFERENCE!>Beta<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val i = <!UNRESOLVED_REFERENCE!>Gamma<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = <!UNRESOLVED_REFERENCE!>FromAlpha<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val l = <!UNRESOLVED_REFERENCE!>FromBeta<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val m = <!UNRESOLVED_REFERENCE!>FromGamma<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val p = <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val q = <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = <!UNRESOLVED_REFERENCE!>FromDelta<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesNew.txt

@@ -0,0 +1,239 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: [ERROR : Type for A::foo]
+    public final val b: [ERROR : Type for A::foo]
+    public final val c: kotlin.reflect.KFunction1<O.A.FromA, kotlin.Int>
+    public final val d: kotlin.reflect.KFunction1<O.B.FromB, kotlin.Int>
+    public final val e: [ERROR : Type for FromCompanionA::foo]
+    public final val f: [ERROR : Type for FromCompanionB::foo]
+    public final val g: [ERROR : Type for Alpha::foo]
+    public final val h: [ERROR : Type for Beta::foo]
+    public final val i: [ERROR : Type for Gamma::foo]
+    public final val k: [ERROR : Type for FromAlpha::foo]
+    public final val l: [ERROR : Type for FromBeta::foo]
+    public final val m: [ERROR : Type for FromGamma::foo]
+    public final val n: kotlin.reflect.KFunction1<C.Companion.FromCompanionC, kotlin.Int>
+    public final val o: [ERROR : Type for FromCompanionAlpha::foo]
+    public final val p: [ERROR : Type for FromCompanionBeta::foo]
+    public final val q: [ERROR : Type for FromCompanionGamma::foo]
+    public final val r: [ERROR : Type for FromDelta::foo]
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class O {
+    public constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesOld.kt

@@ -0,0 +1,142 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// See KT-21515 for a class diagram and details
+
+// class is to prevent accidental short-name import
+class O {
+    open class Alpha {
+        open fun foo() = 42
+
+        class FromAlpha {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionAlpha {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class Beta : Alpha() {
+        override fun foo() = 42
+
+        class FromBeta {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionBeta {
+                fun foo() = 42
+            }
+        }
+    }
+
+
+    open class A {
+        open fun foo() = 42
+
+        class FromA {
+            fun foo() = 42
+        }
+
+        companion object : Beta() {
+            class FromCompanionA {
+                fun foo() = 42
+            }
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open fun foo() = 42
+
+        class FromFarAway {
+            fun foo() = 42
+        }
+
+    }
+
+    open class Gamma {
+        open fun foo() = 42
+
+        class FromGamma {
+            fun foo() = 42
+        }
+
+        companion object : FarAway() {
+            class FromCompanionGamma {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class B : A() {
+        override fun foo() = 42
+
+        class FromB {
+            fun foo() = 42
+        }
+
+        companion object : Gamma() {
+            override fun foo() = 42
+
+            class FromCompanionB {
+                fun foo() = 42
+            }
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open fun foo() = 42
+    class FromDelta {
+        fun foo() = 42
+    }
+}
+
+class C : O.B() {
+    override fun foo() = 42
+
+    companion object : Delta() {
+        class FromCompanionC {
+            fun foo() = 42
+        }
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = FromA::foo
+    val d = FromB::foo
+
+    // VISIBLE: Classifiers from our own companion
+    val n = FromCompanionC::foo
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = <!UNRESOLVED_REFERENCE!>A<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val b = <!UNRESOLVED_REFERENCE!>A<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionA<!>::foo
+    val f = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionB<!>::foo
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = <!UNRESOLVED_REFERENCE!>Alpha<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val h = <!UNRESOLVED_REFERENCE!>Beta<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val i = <!UNRESOLVED_REFERENCE!>Gamma<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromAlpha<!>::foo
+    val l = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBeta<!>::foo
+    val m = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromGamma<!>::foo
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val p = <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+    val q = <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>::<!DEBUG_INFO_MISSING_UNRESOLVED!>foo<!>
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromDelta<!>::foo
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesOld.txt

@@ -0,0 +1,239 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: [ERROR : Type for A::foo]
+    public final val b: [ERROR : Type for A::foo]
+    public final val c: kotlin.reflect.KFunction1<O.A.FromA, kotlin.Int>
+    public final val d: kotlin.reflect.KFunction1<O.B.FromB, kotlin.Int>
+    public final val e: kotlin.reflect.KFunction1<O.A.Companion.FromCompanionA, kotlin.Int>
+    public final val f: kotlin.reflect.KFunction1<O.B.Companion.FromCompanionB, kotlin.Int>
+    public final val g: [ERROR : Type for Alpha::foo]
+    public final val h: [ERROR : Type for Beta::foo]
+    public final val i: [ERROR : Type for Gamma::foo]
+    public final val k: kotlin.reflect.KFunction1<O.Alpha.FromAlpha, kotlin.Int>
+    public final val l: kotlin.reflect.KFunction1<O.Beta.FromBeta, kotlin.Int>
+    public final val m: kotlin.reflect.KFunction1<O.Gamma.FromGamma, kotlin.Int>
+    public final val n: kotlin.reflect.KFunction1<C.Companion.FromCompanionC, kotlin.Int>
+    public final val o: [ERROR : Type for FromCompanionAlpha::foo]
+    public final val p: [ERROR : Type for FromCompanionBeta::foo]
+    public final val q: [ERROR : Type for FromCompanionGamma::foo]
+    public final val r: kotlin.reflect.KFunction1<Delta.FromDelta, kotlin.Int>
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class O {
+    public constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesOldComplexCases.kt

@@ -0,0 +1,69 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+
+// ===== Case 1: LHS is a class
+//
+object A {
+    open class Base {
+        companion object {
+            class FromBaseCompanion {
+                fun foo() = 42
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBaseCompanion<!>::foo
+    }
+}
+
+// ===== Case 2: LHS is a class with companion object, function comes from class
+
+object B {
+    open class Base {
+        companion object {
+            class FromBaseCompanion {
+                fun foo() = 42
+
+                companion object {}
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBaseCompanion<!>::foo
+    }
+}
+
+// ==== Case 3: LHS is a class with companion object, function comes from companion
+
+object C {
+    open class Base {
+        companion object {
+            class FromBaseCompanion {
+                companion object {
+                    fun foo() = 42
+                }
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBaseCompanion<!>::<!UNRESOLVED_REFERENCE!>foo<!>
+    }
+}
+
+// ==== Case 4: LHS is an object
+
+object D {
+    open class Base {
+        companion object {
+            object FromBaseCompanion {
+                fun foo() = 42
+            }
+        }
+    }
+
+    class Derived : Base() {
+        val a = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBaseCompanion<!>::foo
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesOldComplexCases.txt

@@ -0,0 +1,163 @@
+package
+
+public object A {
+    private constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBaseCompanion {
+                public constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+    }
+
+    public final class Derived : A.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction1<A.Base.Companion.FromBaseCompanion, kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object B {
+    private constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBaseCompanion {
+                public constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public companion object Companion {
+                    private constructor Companion()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    public final class Derived : B.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction1<B.Base.Companion.FromBaseCompanion, kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object C {
+    private constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromBaseCompanion {
+                public constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public companion object Companion {
+                    private constructor Companion()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public final fun foo(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    public final class Derived : C.Base {
+        public constructor Derived()
+        public final val a: [ERROR : Type for FromBaseCompanion::foo]
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object D {
+    private constructor D()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public object FromBaseCompanion {
+                private constructor FromBaseCompanion()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+    }
+
+    public final class Derived : D.Base {
+        public constructor Derived()
+        public final val a: kotlin.reflect.KFunction0<kotlin.Int>
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesWithQualificationNew.kt

@@ -0,0 +1,142 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// See KT-21515 for a class diagram and details
+
+// class is to prevent accidental short-name import
+class O {
+    open class Alpha {
+        open fun foo() = 42
+
+        class FromAlpha {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionAlpha {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class Beta : Alpha() {
+        override fun foo() = 42
+
+        class FromBeta {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionBeta {
+                fun foo() = 42
+            }
+        }
+    }
+
+
+    open class A {
+        open fun foo() = 42
+
+        class FromA {
+            fun foo() = 42
+        }
+
+        companion object : Beta() {
+            class FromCompanionA {
+                fun foo() = 42
+            }
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open fun foo() = 42
+
+        class FromFarAway {
+            fun foo() = 42
+        }
+
+    }
+
+    open class Gamma {
+        open fun foo() = 42
+
+        class FromGamma {
+            fun foo() = 42
+        }
+
+        companion object : FarAway() {
+            class FromCompanionGamma {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class B : A() {
+        override fun foo() = 42
+
+        class FromB {
+            fun foo() = 42
+        }
+
+        companion object : Gamma() {
+            override fun foo() = 42
+
+            class FromCompanionB {
+                fun foo() = 42
+            }
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open fun foo() = 42
+    class FromDelta {
+        fun foo() = 42
+    }
+}
+
+class C : O.B() {
+    override fun foo() = 42
+
+    companion object : Delta() {
+        class FromCompanionC {
+            fun foo() = 42
+        }
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = O.A.FromA::foo
+    val d = O.B.FromB::foo
+
+    // VISIBLE: Classifiers from our own companion
+    val n = C.Companion.FromCompanionC::foo
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = O.A::foo
+    val b = O.A::foo
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = O.A.Companion.FromCompanionA::foo
+    val f = O.B.Companion.FromCompanionB::foo
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = O.Alpha::foo
+    val h = O.Beta::foo
+    val i = O.Gamma::foo
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = O.Alpha.FromAlpha::foo
+    val l = O.Beta.FromBeta::foo
+    val m = O.Gamma.FromGamma::foo
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = O.Alpha.Companion.FromCompanionAlpha::foo
+    val p = O.Beta.Companion.FromCompanionBeta::foo
+    val q = O.Gamma.Companion.FromCompanionGamma::foo
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = Delta.FromDelta::foo
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesWithQualificationNew.txt

@@ -0,0 +1,239 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: kotlin.reflect.KFunction1<O.A, kotlin.Int>
+    public final val b: kotlin.reflect.KFunction1<O.A, kotlin.Int>
+    public final val c: kotlin.reflect.KFunction1<O.A.FromA, kotlin.Int>
+    public final val d: kotlin.reflect.KFunction1<O.B.FromB, kotlin.Int>
+    public final val e: kotlin.reflect.KFunction1<O.A.Companion.FromCompanionA, kotlin.Int>
+    public final val f: kotlin.reflect.KFunction1<O.B.Companion.FromCompanionB, kotlin.Int>
+    public final val g: kotlin.reflect.KFunction1<O.Alpha, kotlin.Int>
+    public final val h: kotlin.reflect.KFunction1<O.Beta, kotlin.Int>
+    public final val i: kotlin.reflect.KFunction1<O.Gamma, kotlin.Int>
+    public final val k: kotlin.reflect.KFunction1<O.Alpha.FromAlpha, kotlin.Int>
+    public final val l: kotlin.reflect.KFunction1<O.Beta.FromBeta, kotlin.Int>
+    public final val m: kotlin.reflect.KFunction1<O.Gamma.FromGamma, kotlin.Int>
+    public final val n: kotlin.reflect.KFunction1<C.Companion.FromCompanionC, kotlin.Int>
+    public final val o: kotlin.reflect.KFunction1<O.Alpha.Companion.FromCompanionAlpha, kotlin.Int>
+    public final val p: kotlin.reflect.KFunction1<O.Beta.Companion.FromCompanionBeta, kotlin.Int>
+    public final val q: kotlin.reflect.KFunction1<O.Gamma.Companion.FromCompanionGamma, kotlin.Int>
+    public final val r: kotlin.reflect.KFunction1<Delta.FromDelta, kotlin.Int>
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class O {
+    public constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesWithQualificationOld.kt

@@ -0,0 +1,142 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// See KT-21515 for a class diagram and details
+
+// class is to prevent accidental short-name import
+class O {
+    open class Alpha {
+        open fun foo() = 42
+
+        class FromAlpha {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionAlpha {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class Beta : Alpha() {
+        override fun foo() = 42
+
+        class FromBeta {
+            fun foo() = 42
+        }
+
+        companion object {
+            class FromCompanionBeta {
+                fun foo() = 42
+            }
+        }
+    }
+
+
+    open class A {
+        open fun foo() = 42
+
+        class FromA {
+            fun foo() = 42
+        }
+
+        companion object : Beta() {
+            class FromCompanionA {
+                fun foo() = 42
+            }
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open fun foo() = 42
+
+        class FromFarAway {
+            fun foo() = 42
+        }
+
+    }
+
+    open class Gamma {
+        open fun foo() = 42
+
+        class FromGamma {
+            fun foo() = 42
+        }
+
+        companion object : FarAway() {
+            class FromCompanionGamma {
+                fun foo() = 42
+            }
+        }
+    }
+
+    open class B : A() {
+        override fun foo() = 42
+
+        class FromB {
+            fun foo() = 42
+        }
+
+        companion object : Gamma() {
+            override fun foo() = 42
+
+            class FromCompanionB {
+                fun foo() = 42
+            }
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open fun foo() = 42
+    class FromDelta {
+        fun foo() = 42
+    }
+}
+
+class C : O.B() {
+    override fun foo() = 42
+
+    companion object : Delta() {
+        class FromCompanionC {
+            fun foo() = 42
+        }
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = O.A.FromA::foo
+    val d = O.B.FromB::foo
+
+    // VISIBLE: Classifiers from our own companion
+    val n = FromCompanionC::foo
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = O.A::foo
+    val b = O.A::foo
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = O.A.Companion.FromCompanionA::foo
+    val f = O.B.Companion.FromCompanionB::foo
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = O.Alpha::foo
+    val h = O.Beta::foo
+    val i = O.Gamma::foo
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = O.Alpha.FromAlpha::foo
+    val l = O.Beta.FromBeta::foo
+    val m = O.Gamma.FromGamma::foo
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = O.Alpha.Companion.FromCompanionAlpha::foo
+    val p = O.Beta.Companion.FromCompanionBeta::foo
+    val q = O.Gamma.Companion.FromCompanionGamma::foo
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = Delta.FromDelta::foo
+}

compiler/testData/diagnostics/tests/objects/kt21515/callableReferencesWithQualificationOld.txt

@@ -0,0 +1,239 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: kotlin.reflect.KFunction1<O.A, kotlin.Int>
+    public final val b: kotlin.reflect.KFunction1<O.A, kotlin.Int>
+    public final val c: kotlin.reflect.KFunction1<O.A.FromA, kotlin.Int>
+    public final val d: kotlin.reflect.KFunction1<O.B.FromB, kotlin.Int>
+    public final val e: kotlin.reflect.KFunction1<O.A.Companion.FromCompanionA, kotlin.Int>
+    public final val f: kotlin.reflect.KFunction1<O.B.Companion.FromCompanionB, kotlin.Int>
+    public final val g: kotlin.reflect.KFunction1<O.Alpha, kotlin.Int>
+    public final val h: kotlin.reflect.KFunction1<O.Beta, kotlin.Int>
+    public final val i: kotlin.reflect.KFunction1<O.Gamma, kotlin.Int>
+    public final val k: kotlin.reflect.KFunction1<O.Alpha.FromAlpha, kotlin.Int>
+    public final val l: kotlin.reflect.KFunction1<O.Beta.FromBeta, kotlin.Int>
+    public final val m: kotlin.reflect.KFunction1<O.Gamma.FromGamma, kotlin.Int>
+    public final val n: kotlin.reflect.KFunction1<C.Companion.FromCompanionC, kotlin.Int>
+    public final val o: kotlin.reflect.KFunction1<O.Alpha.Companion.FromCompanionAlpha, kotlin.Int>
+    public final val p: kotlin.reflect.KFunction1<O.Beta.Companion.FromCompanionBeta, kotlin.Int>
+    public final val q: kotlin.reflect.KFunction1<O.Gamma.Companion.FromCompanionGamma, kotlin.Int>
+    public final val r: kotlin.reflect.KFunction1<Delta.FromDelta, kotlin.Int>
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class O {
+    public constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public final fun foo(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public final fun foo(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectNew.kt

@@ -0,0 +1,99 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c: FromA? = null
+    val d: FromB? = null
+
+    // VISIBLE: Classifiers from our own companion
+    val n: FromCompanionC? = null
+
+    // INVISIBLE: direct superclasses themselves.
+    val a: <!UNRESOLVED_REFERENCE!>A<!>? = null
+    val b: <!UNRESOLVED_REFERENCE!>B<!>? = null
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e: <!UNRESOLVED_REFERENCE!>FromCompanionA<!>? = null
+    val f: <!UNRESOLVED_REFERENCE!>FromCompanionB<!>? = null
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g: <!UNRESOLVED_REFERENCE!>Alpha<!>? = null
+    val h: <!UNRESOLVED_REFERENCE!>Beta<!>? = null
+    val i: <!UNRESOLVED_REFERENCE!>Gamma<!>? = null
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k: <!UNRESOLVED_REFERENCE!>FromAlpha<!>? = null
+    val l: <!UNRESOLVED_REFERENCE!>FromBeta<!>? = null
+    val m: <!UNRESOLVED_REFERENCE!>FromGamma<!>? = null
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o: <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>? = null
+    val p: <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>? = null
+    val q: <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>? = null
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r: <!UNRESOLVED_REFERENCE!>FromDelta<!>? = null
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectNew.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: [ERROR : A]?
+    public final val b: [ERROR : B]?
+    public final val c: O.A.FromA? = null
+    public final val d: O.B.FromB? = null
+    public final val e: [ERROR : FromCompanionA]?
+    public final val f: [ERROR : FromCompanionB]?
+    public final val g: [ERROR : Alpha]?
+    public final val h: [ERROR : Beta]?
+    public final val i: [ERROR : Gamma]?
+    public final val k: [ERROR : FromAlpha]?
+    public final val l: [ERROR : FromBeta]?
+    public final val m: [ERROR : FromGamma]?
+    public final val n: C.Companion.FromCompanionC? = null
+    public final val o: [ERROR : FromCompanionAlpha]?
+    public final val p: [ERROR : FromCompanionBeta]?
+    public final val q: [ERROR : FromCompanionGamma]?
+    public final val r: [ERROR : FromDelta]?
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectOld.kt

@@ -0,0 +1,98 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c: FromA? = null
+    val d: FromB? = null
+
+    // VISIBLE: Classifiers from our own companion
+    val n: FromCompanionC? = null
+
+    // INVISIBLE: direct superclasses themselves.
+    val a: <!UNRESOLVED_REFERENCE!>A<!>? = null
+    val b: <!UNRESOLVED_REFERENCE!>B<!>? = null
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e: <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionA<!>? = null
+    val f: <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionB<!>? = null
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g: <!UNRESOLVED_REFERENCE!>Alpha<!>? = null
+    val h: <!UNRESOLVED_REFERENCE!>Beta<!>? = null
+    val i: <!UNRESOLVED_REFERENCE!>Gamma<!>? = null
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k: <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromAlpha<!>? = null
+    val l: <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBeta<!>? = null
+    val m: <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromGamma<!>? = null
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o: <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>? = null
+    val p: <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>? = null
+    val q: <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>? = null
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r: <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromDelta<!>? = null
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectOld.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: [ERROR : A]?
+    public final val b: [ERROR : B]?
+    public final val c: O.A.FromA? = null
+    public final val d: O.B.FromB? = null
+    public final val e: O.A.Companion.FromCompanionA? = null
+    public final val f: O.B.Companion.FromCompanionB? = null
+    public final val g: [ERROR : Alpha]?
+    public final val h: [ERROR : Beta]?
+    public final val i: [ERROR : Gamma]?
+    public final val k: O.Alpha.FromAlpha? = null
+    public final val l: O.Beta.FromBeta? = null
+    public final val m: O.Gamma.FromGamma? = null
+    public final val n: C.Companion.FromCompanionC? = null
+    public final val o: [ERROR : FromCompanionAlpha]?
+    public final val p: [ERROR : FromCompanionBeta]?
+    public final val q: [ERROR : FromCompanionGamma]?
+    public final val r: Delta.FromDelta? = null
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectWithQualificationNew.kt

@@ -0,0 +1,99 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c: O.A.FromA? = null
+    val d: O.B.FromB? = null
+
+    // VISIBLE: Classifiers from our own companion
+    val n: C.Companion.FromCompanionC? = null
+
+    // INVISIBLE: direct superclasses themselves.
+    val a: O.A? = null
+    val b: O.B? = null
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e: O.A.Companion.FromCompanionA? = null
+    val f: O.B.Companion.FromCompanionB? = null
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g: O.Alpha? = null
+    val h: O.Beta? = null
+    val i: O.Gamma? = null
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k: O.Alpha.FromAlpha? = null
+    val l: O.Beta.FromBeta? = null
+    val m: O.Gamma.FromGamma? = null
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o: O.Alpha.Companion.FromCompanionAlpha? = null
+    val p: O.Beta.Companion.FromCompanionBeta? = null
+    val q: O.Gamma.Companion.FromCompanionGamma? = null
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r: Delta.FromDelta? = null
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectWithQualificationNew.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: O.A? = null
+    public final val b: O.B? = null
+    public final val c: O.A.FromA? = null
+    public final val d: O.B.FromB? = null
+    public final val e: O.A.Companion.FromCompanionA? = null
+    public final val f: O.B.Companion.FromCompanionB? = null
+    public final val g: O.Alpha? = null
+    public final val h: O.Beta? = null
+    public final val i: O.Gamma? = null
+    public final val k: O.Alpha.FromAlpha? = null
+    public final val l: O.Beta.FromBeta? = null
+    public final val m: O.Gamma.FromGamma? = null
+    public final val n: C.Companion.FromCompanionC? = null
+    public final val o: O.Alpha.Companion.FromCompanionAlpha? = null
+    public final val p: O.Beta.Companion.FromCompanionBeta? = null
+    public final val q: O.Gamma.Companion.FromCompanionGamma? = null
+    public final val r: Delta.FromDelta? = null
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectWithQualificationOld.kt

@@ -0,0 +1,98 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c: O.A.FromA? = null
+    val d: O.B.FromB? = null
+
+    // VISIBLE: Classifiers from our own companion
+    val n: C.Companion.FromCompanionC? = null
+
+    // INVISIBLE: direct superclasses themselves.
+    val a: O.A? = null
+    val b: O.B? = null
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e: O.A.Companion.FromCompanionA? = null
+    val f: O.B.Companion.FromCompanionB? = null
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g: O.Alpha? = null
+    val h: O.Beta? = null
+    val i: O.Gamma? = null
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k: O.Alpha.FromAlpha? = null
+    val l: O.Beta.FromBeta? = null
+    val m: O.Gamma.FromGamma? = null
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o: O.Alpha.Companion.FromCompanionAlpha? = null
+    val p: O.Beta.Companion.FromCompanionBeta? = null
+    val q: O.Gamma.Companion.FromCompanionGamma? = null
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r: Delta.FromDelta? = null
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierFromCompanionObjectWithQualificationOld.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: O.A? = null
+    public final val b: O.B? = null
+    public final val c: O.A.FromA? = null
+    public final val d: O.B.FromB? = null
+    public final val e: O.A.Companion.FromCompanionA? = null
+    public final val f: O.B.Companion.FromCompanionB? = null
+    public final val g: O.Alpha? = null
+    public final val h: O.Beta? = null
+    public final val i: O.Gamma? = null
+    public final val k: O.Alpha.FromAlpha? = null
+    public final val l: O.Beta.FromBeta? = null
+    public final val m: O.Gamma.FromGamma? = null
+    public final val n: C.Companion.FromCompanionC? = null
+    public final val o: O.Alpha.Companion.FromCompanionAlpha? = null
+    public final val p: O.Beta.Companion.FromCompanionBeta? = null
+    public final val q: O.Gamma.Companion.FromCompanionGamma? = null
+    public final val r: Delta.FromDelta? = null
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierIsVisibleByTwoPaths.kt

@@ -0,0 +1,17 @@
+open class A {
+    class FromA {
+        fun foo() = 42
+    }
+}
+
+class B : A() {
+    companion object : A() { }
+
+    // we're seeing FromA here by two paths: one is deprecated (via companion object), and another one is not,
+    // so we shouldn't see deprecation warning
+    val a: FromA? = null
+
+    val b = FromA::foo
+
+    val c = FromA()
+}

compiler/testData/diagnostics/tests/objects/kt21515/classifierIsVisibleByTwoPaths.txt

@@ -0,0 +1,33 @@
+package
+
+public open class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromA {
+        public constructor FromA()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class B : A {
+    public constructor B()
+    public final val a: A.FromA? = null
+    public final val b: kotlin.reflect.KFunction1<A.FromA, kotlin.Int>
+    public final val c: A.FromA
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : A {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedNew.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a open class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        open class FromAlpha
+
+        companion object {
+            open class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        open class FromBeta
+
+        companion object {
+            open class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        open class FromA
+
+        companion object : Beta() {
+            open class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open class FromFarAway
+
+    }
+
+    open class Gamma {
+        open class FromGamma
+        companion object : FarAway() {
+            open class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        open class FromB
+
+        companion object : Gamma() {
+            open class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open class FromDelta
+}
+
+open class C : O.B() {
+    companion object : Delta() {
+        open class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    open class c : FromA()
+    open class d : FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    open class n : FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    open class a : <!UNRESOLVED_REFERENCE!>A<!>()
+    open class b : <!UNRESOLVED_REFERENCE!>B<!>()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    open class e : <!UNRESOLVED_REFERENCE!>FromCompanionA<!>()
+    open class f : <!UNRESOLVED_REFERENCE!>FromCompanionB<!>()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    open class g : <!UNRESOLVED_REFERENCE!>Alpha<!>()
+    open class h : <!UNRESOLVED_REFERENCE!>Beta<!>()
+    open class i : <!UNRESOLVED_REFERENCE!>Gamma<!>()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    open class k : <!UNRESOLVED_REFERENCE!>FromAlpha<!>()
+    open class l : <!UNRESOLVED_REFERENCE!>FromBeta<!>()
+    open class m : <!UNRESOLVED_REFERENCE!>FromGamma<!>()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    open class o : <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>()
+    open class p : <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>()
+    open class q : <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    open class r : <!UNRESOLVED_REFERENCE!>FromDelta<!>()
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedNew.txt

@@ -0,0 +1,316 @@
+package
+
+public open class C : O.B {
+    public constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class a {
+        public constructor a()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class b {
+        public constructor b()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class c : O.A.FromA {
+        public constructor c()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class d : O.B.FromB {
+        public constructor d()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class e {
+        public constructor e()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class f {
+        public constructor f()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class g {
+        public constructor g()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class h {
+        public constructor h()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class i {
+        public constructor i()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class k {
+        public constructor k()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class l {
+        public constructor l()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class m {
+        public constructor m()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class n : C.Companion.FromCompanionC {
+        public constructor n()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class o {
+        public constructor o()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class p {
+        public constructor p()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class q {
+        public constructor q()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class r {
+        public constructor r()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedOld.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a open class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        open class FromAlpha
+
+        companion object {
+            open class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        open class FromBeta
+
+        companion object {
+            open class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        open class FromA
+
+        companion object : Beta() {
+            open class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open class FromFarAway
+
+    }
+
+    open class Gamma {
+        open class FromGamma
+        companion object : FarAway() {
+            open class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        open class FromB
+
+        companion object : Gamma() {
+            open class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open class FromDelta
+}
+
+open class C : O.B() {
+    companion object : Delta() {
+        open class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    open class c : FromA()
+    open class d : FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    open class n : FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    open class a : <!UNRESOLVED_REFERENCE!>A<!>()
+    open class b : <!UNRESOLVED_REFERENCE!>B<!>()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    open class e : <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionA<!>()
+    open class f : <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionB<!>()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    open class g : <!UNRESOLVED_REFERENCE!>Alpha<!>()
+    open class h : <!UNRESOLVED_REFERENCE!>Beta<!>()
+    open class i : <!UNRESOLVED_REFERENCE!>Gamma<!>()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    open class k : <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromAlpha<!>()
+    open class l : <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBeta<!>()
+    open class m : <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromGamma<!>()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    open class o : <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>()
+    open class p : <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>()
+    open class q : <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    open class r : <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromDelta<!>()
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedOld.txt

@@ -0,0 +1,316 @@
+package
+
+public open class C : O.B {
+    public constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class a {
+        public constructor a()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class b {
+        public constructor b()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class c : O.A.FromA {
+        public constructor c()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class d : O.B.FromB {
+        public constructor d()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class e : O.A.Companion.FromCompanionA {
+        public constructor e()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class f : O.B.Companion.FromCompanionB {
+        public constructor f()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class g {
+        public constructor g()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class h {
+        public constructor h()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class i {
+        public constructor i()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class k : O.Alpha.FromAlpha {
+        public constructor k()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class l : O.Beta.FromBeta {
+        public constructor l()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class m : O.Gamma.FromGamma {
+        public constructor m()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class n : C.Companion.FromCompanionC {
+        public constructor n()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class o {
+        public constructor o()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class p {
+        public constructor p()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class q {
+        public constructor q()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class r : Delta.FromDelta {
+        public constructor r()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedWithQualificationNew.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a open class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        open class FromAlpha
+
+        companion object {
+            open class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        open class FromBeta
+
+        companion object {
+            open class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        open class FromA
+
+        companion object : Beta() {
+            open class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open class FromFarAway
+
+    }
+
+    open class Gamma {
+        open class FromGamma
+        companion object : FarAway() {
+            open class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        open class FromB
+
+        companion object : Gamma() {
+            open class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open class FromDelta
+}
+
+open class C : O.B() {
+    companion object : Delta() {
+        open class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    open class c : O.A.FromA()
+    open class d : O.B.FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    open class n : C.Companion.FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    open class a : O.A()
+    open class b : O.B()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    open class e : O.A.Companion.FromCompanionA()
+    open class f : O.B.Companion.FromCompanionB()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    open class g : O.Alpha()
+    open class h : O.Beta()
+    open class i : O.Gamma()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    open class k : O.Alpha.FromAlpha()
+    open class l : O.Beta.FromBeta()
+    open class m : O.Gamma.FromGamma()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    open class o : O.Alpha.Companion.FromCompanionAlpha()
+    open class p : O.Beta.Companion.FromCompanionBeta()
+    open class q : O.Gamma.Companion.FromCompanionGamma()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    open class r : Delta.FromDelta()
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedWithQualificationNew.txt

@@ -0,0 +1,316 @@
+package
+
+public open class C : O.B {
+    public constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class a : O.A {
+        public constructor a()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class b : O.B {
+        public constructor b()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class c : O.A.FromA {
+        public constructor c()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class d : O.B.FromB {
+        public constructor d()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class e : O.A.Companion.FromCompanionA {
+        public constructor e()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class f : O.B.Companion.FromCompanionB {
+        public constructor f()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class g : O.Alpha {
+        public constructor g()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class h : O.Beta {
+        public constructor h()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class i : O.Gamma {
+        public constructor i()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class k : O.Alpha.FromAlpha {
+        public constructor k()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class l : O.Beta.FromBeta {
+        public constructor l()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class m : O.Gamma.FromGamma {
+        public constructor m()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class n : C.Companion.FromCompanionC {
+        public constructor n()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class o : O.Alpha.Companion.FromCompanionAlpha {
+        public constructor o()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class p : O.Beta.Companion.FromCompanionBeta {
+        public constructor p()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class q : O.Gamma.Companion.FromCompanionGamma {
+        public constructor q()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class r : Delta.FromDelta {
+        public constructor r()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedWithQualificationOld.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a open class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        open class FromAlpha
+
+        companion object {
+            open class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        open class FromBeta
+
+        companion object {
+            open class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        open class FromA
+
+        companion object : Beta() {
+            open class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        open class FromFarAway
+
+    }
+
+    open class Gamma {
+        open class FromGamma
+        companion object : FarAway() {
+            open class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        open class FromB
+
+        companion object : Gamma() {
+            open class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    open class FromDelta
+}
+
+open class C : O.B() {
+    companion object : Delta() {
+        open class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    open class c : O.A.FromA()
+    open class d : O.B.FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    open class n : C.Companion.FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    open class a : O.A()
+    open class b : O.B()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    open class e : O.A.Companion.FromCompanionA()
+    open class f : O.B.Companion.FromCompanionB()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    open class g : O.Alpha()
+    open class h : O.Beta()
+    open class i : O.Gamma()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    open class k : O.Alpha.FromAlpha()
+    open class l : O.Beta.FromBeta()
+    open class m : O.Gamma.FromGamma()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    open class o : O.Alpha.Companion.FromCompanionAlpha()
+    open class p : O.Beta.Companion.FromCompanionBeta()
+    open class q : O.Gamma.Companion.FromCompanionGamma()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    open class r : Delta.FromDelta()
+}

compiler/testData/diagnostics/tests/objects/kt21515/inheritedFromDeprecatedWithQualificationOld.txt

@@ -0,0 +1,316 @@
+package
+
+public open class C : O.B {
+    public constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class a : O.A {
+        public constructor a()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class b : O.B {
+        public constructor b()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class c : O.A.FromA {
+        public constructor c()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class d : O.B.FromB {
+        public constructor d()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class e : O.A.Companion.FromCompanionA {
+        public constructor e()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class f : O.B.Companion.FromCompanionB {
+        public constructor f()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class g : O.Alpha {
+        public constructor g()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class h : O.Beta {
+        public constructor h()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class i : O.Gamma {
+        public constructor i()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class k : O.Alpha.FromAlpha {
+        public constructor k()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class l : O.Beta.FromBeta {
+        public constructor l()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class m : O.Gamma.FromGamma {
+        public constructor m()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class n : C.Companion.FromCompanionC {
+        public constructor n()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class o : O.Alpha.Companion.FromCompanionAlpha {
+        public constructor o()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class p : O.Beta.Companion.FromCompanionBeta {
+        public constructor p()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class q : O.Gamma.Companion.FromCompanionGamma {
+        public constructor q()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public open class r : Delta.FromDelta {
+        public constructor r()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public open class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public open class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public open class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorNew.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = FromA()
+    val d = FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    val n = FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = <!UNRESOLVED_REFERENCE!>A<!>()
+    val b = <!UNRESOLVED_REFERENCE!>B<!>()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = <!UNRESOLVED_REFERENCE!>FromCompanionA<!>()
+    val f = <!UNRESOLVED_REFERENCE!>FromCompanionB<!>()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = <!UNRESOLVED_REFERENCE!>Alpha<!>()
+    val h = <!UNRESOLVED_REFERENCE!>Beta<!>()
+    val i = <!UNRESOLVED_REFERENCE!>Gamma<!>()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = <!UNRESOLVED_REFERENCE!>FromAlpha<!>()
+    val l = <!UNRESOLVED_REFERENCE!>FromBeta<!>()
+    val m = <!UNRESOLVED_REFERENCE!>FromGamma<!>()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>()
+    val p = <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>()
+    val q = <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = <!UNRESOLVED_REFERENCE!>FromDelta<!>()
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorNew.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: [ERROR : Type for A()]
+    public final val b: [ERROR : Type for B()]
+    public final val c: O.A.FromA
+    public final val d: O.B.FromB
+    public final val e: [ERROR : Type for FromCompanionA()]
+    public final val f: [ERROR : Type for FromCompanionB()]
+    public final val g: [ERROR : Type for Alpha()]
+    public final val h: [ERROR : Type for Beta()]
+    public final val i: [ERROR : Type for Gamma()]
+    public final val k: [ERROR : Type for FromAlpha()]
+    public final val l: [ERROR : Type for FromBeta()]
+    public final val m: [ERROR : Type for FromGamma()]
+    public final val n: C.Companion.FromCompanionC
+    public final val o: [ERROR : Type for FromCompanionAlpha()]
+    public final val p: [ERROR : Type for FromCompanionBeta()]
+    public final val q: [ERROR : Type for FromCompanionGamma()]
+    public final val r: [ERROR : Type for FromDelta()]
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorOld.kt

@@ -0,0 +1,99 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = FromA()
+    val d = FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    val n = FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = <!UNRESOLVED_REFERENCE!>A<!>()
+    val b = <!UNRESOLVED_REFERENCE!>B<!>()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionA()<!>
+    val f = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromCompanionB()<!>
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = <!UNRESOLVED_REFERENCE!>Alpha<!>()
+    val h = <!UNRESOLVED_REFERENCE!>Beta<!>()
+    val i = <!UNRESOLVED_REFERENCE!>Gamma<!>()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromAlpha()<!>
+    val l = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromBeta()<!>
+    val m = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromGamma()<!>
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = <!UNRESOLVED_REFERENCE!>FromCompanionAlpha<!>()
+    val p = <!UNRESOLVED_REFERENCE!>FromCompanionBeta<!>()
+    val q = <!UNRESOLVED_REFERENCE!>FromCompanionGamma<!>()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = <!DEPRECATED_ACCESS_BY_SHORT_NAME!>FromDelta()<!>
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorOld.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: [ERROR : Type for A()]
+    public final val b: [ERROR : Type for B()]
+    public final val c: O.A.FromA
+    public final val d: O.B.FromB
+    public final val e: O.A.Companion.FromCompanionA
+    public final val f: O.B.Companion.FromCompanionB
+    public final val g: [ERROR : Type for Alpha()]
+    public final val h: [ERROR : Type for Beta()]
+    public final val i: [ERROR : Type for Gamma()]
+    public final val k: O.Alpha.FromAlpha
+    public final val l: O.Beta.FromBeta
+    public final val m: O.Gamma.FromGamma
+    public final val n: C.Companion.FromCompanionC
+    public final val o: [ERROR : Type for FromCompanionAlpha()]
+    public final val p: [ERROR : Type for FromCompanionBeta()]
+    public final val q: [ERROR : Type for FromCompanionGamma()]
+    public final val r: Delta.FromDelta
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorWithQualificationNew.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: +ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = O.A.FromA()
+    val d = O.B.FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    val n = C.Companion.FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = O.A()
+    val b = O.B()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = O.A.Companion.FromCompanionA()
+    val f = O.B.Companion.FromCompanionB()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = O.Alpha()
+    val h = O.Beta()
+    val i = O.Gamma()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = O.Alpha.FromAlpha()
+    val l = O.Beta.FromBeta()
+    val m = O.Gamma.FromGamma()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = O.Alpha.Companion.FromCompanionAlpha()
+    val p = O.Beta.Companion.FromCompanionBeta()
+    val q = O.Gamma.Companion.FromCompanionGamma()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = Delta.FromDelta()
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorWithQualificationNew.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: O.A
+    public final val b: O.B
+    public final val c: O.A.FromA
+    public final val d: O.B.FromB
+    public final val e: O.A.Companion.FromCompanionA
+    public final val f: O.B.Companion.FromCompanionB
+    public final val g: O.Alpha
+    public final val h: O.Beta
+    public final val i: O.Gamma
+    public final val k: O.Alpha.FromAlpha
+    public final val l: O.Beta.FromBeta
+    public final val m: O.Gamma.FromGamma
+    public final val n: C.Companion.FromCompanionC
+    public final val o: O.Alpha.Companion.FromCompanionAlpha
+    public final val p: O.Beta.Companion.FromCompanionBeta
+    public final val q: O.Gamma.Companion.FromCompanionGamma
+    public final val r: Delta.FromDelta
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorWithQualificationOld.kt

@@ -0,0 +1,100 @@
+// !LANGUAGE: -ProhibitVisibilityOfNestedClassifiersFromSupertypesOfCompanion
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// See KT-21515 for a class diagram and details
+
+// Object is to prevent accidental short-name import
+object O {
+    open class Alpha {
+        class FromAlpha
+
+        companion object {
+            class FromCompanionAlpha
+        }
+    }
+
+    open class Beta : Alpha() {
+        class FromBeta
+
+        companion object {
+            class FromCompanionBeta
+        }
+    }
+
+
+    open class A {
+        class FromA
+
+        companion object : Beta() {
+            class FromCompanionA
+        }
+    }
+
+//////////////////////////
+
+    open class FarAway {
+        class FromFarAway
+
+    }
+
+    open class Gamma {
+        class FromGamma
+        companion object : FarAway() {
+            class FromCompanionGamma
+        }
+    }
+
+    open class B : A() {
+        class FromB
+
+        companion object : Gamma() {
+            class FromCompanionB
+        }
+    }
+}
+
+///////////////////////////////
+
+
+open class Delta {
+    class FromDelta
+}
+
+class C : O.B() {
+    companion object : Delta() {
+        class FromCompanionC
+    }
+
+    // VISIBLE: Classifiers from direct superclasses
+    val c = O.A.FromA()
+    val d = O.B.FromB()
+
+    // VISIBLE: Classifiers from our own companion
+    val n = C.Companion.FromCompanionC()
+
+    // INVISIBLE: direct superclasses themselves.
+    val a = O.A()
+    val b = O.B()
+
+    // DEPRECATED: Classifiers from companions of direct superclasses
+    val e = O.A.Companion.FromCompanionA()
+    val f = O.B.Companion.FromCompanionB()
+
+    // INVISIBLE: "cousin" supertypes themselves
+    val g = O.Alpha()
+    val h = O.Beta()
+    val i = O.Gamma()
+
+    // DEPRECATED: classifiers from "cousin" superclasses
+    val k = O.Alpha.FromAlpha()
+    val l = O.Beta.FromBeta()
+    val m = O.Gamma.FromGamma()
+
+    // INVISIBLE: We don't see classifiers from companions of "cousin" superclasses
+    val o = O.Alpha.Companion.FromCompanionAlpha()
+    val p = O.Beta.Companion.FromCompanionBeta()
+    val q = O.Gamma.Companion.FromCompanionGamma()
+
+    // DEPRECATED: Classifiers from supertypes of our own companion
+    val r = Delta.FromDelta()
+}

compiler/testData/diagnostics/tests/objects/kt21515/useDeprecatedConstructorWithQualificationOld.txt

@@ -0,0 +1,214 @@
+package
+
+public final class C : O.B {
+    public constructor C()
+    public final val a: O.A
+    public final val b: O.B
+    public final val c: O.A.FromA
+    public final val d: O.B.FromB
+    public final val e: O.A.Companion.FromCompanionA
+    public final val f: O.B.Companion.FromCompanionB
+    public final val g: O.Alpha
+    public final val h: O.Beta
+    public final val i: O.Gamma
+    public final val k: O.Alpha.FromAlpha
+    public final val l: O.Beta.FromBeta
+    public final val m: O.Gamma.FromGamma
+    public final val n: C.Companion.FromCompanionC
+    public final val o: O.Alpha.Companion.FromCompanionAlpha
+    public final val p: O.Beta.Companion.FromCompanionBeta
+    public final val q: O.Gamma.Companion.FromCompanionGamma
+    public final val r: Delta.FromDelta
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion : Delta {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromCompanionC {
+            public constructor FromCompanionC()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}
+
+public open class Delta {
+    public constructor Delta()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class FromDelta {
+        public constructor FromDelta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object O {
+    private constructor O()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Beta {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionA {
+                public constructor FromCompanionA()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromA {
+            public constructor FromA()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Alpha {
+        public constructor Alpha()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionAlpha {
+                public constructor FromCompanionAlpha()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromAlpha {
+            public constructor FromAlpha()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class B : O.A {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.Gamma {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionB {
+                public constructor FromCompanionB()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromB {
+            public constructor FromB()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Beta : O.Alpha {
+        public constructor Beta()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionBeta {
+                public constructor FromCompanionBeta()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromBeta {
+            public constructor FromBeta()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class FarAway {
+        public constructor FarAway()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class FromFarAway {
+            public constructor FromFarAway()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+
+    public open class Gamma {
+        public constructor Gamma()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public companion object Companion : O.FarAway {
+            private constructor Companion()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class FromCompanionGamma {
+                public constructor FromCompanionGamma()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+            }
+        }
+
+        public final class FromGamma {
+            public constructor FromGamma()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+        }
+    }
+}