K2: introduce platform-specific visibility checks for overrides + tests

Related to KT-53197

compiler/testData/diagnostics/tests/visibility/notOverridingInternal.kt

@@ -0,0 +1,24 @@
+// FIR_IDENTICAL
+// MODULE: base
+// FILE: Base.kt
+package base
+
+abstract class Base {
+    fun foo() = internalFoo()
+
+    internal fun internalFoo() {}
+}
+
+// MODULE: impl(base)
+// FILE: Impl.kt
+package impl
+import base.*
+
+class Impl : Base() {
+    fun internalFoo() { /*not an override*/ }
+}
+
+fun foo() {
+    Impl().foo()
+    Impl().internalFoo()
+}

compiler/testData/diagnostics/tests/visibility/notOverridingInternal.txt

@@ -0,0 +1,30 @@
+// -- Module: <base> --
+package
+
+package base {
+
+    public abstract class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        internal final fun internalFoo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+// -- Module: <impl> --
+package
+
+package impl {
+    public fun foo(): kotlin.Unit
+
+    public final class Impl : base.Base {
+        public constructor Impl()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final fun internalFoo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/visibility/notOverridingPackagePrivate.fir.kt

@@ -0,0 +1,23 @@
+// FILE: base/Base.java
+package base;
+
+public abstract class Base {
+    public void foo() {
+        packagePrivateFoo();
+    }
+
+    /* package-private */ void packagePrivateFoo() {};
+}
+
+// FILE: Impl.kt
+package impl
+import base.*
+
+class Impl : Base() {
+    fun packagePrivateFoo() { /*not an override*/ }
+}
+
+fun foo() {
+    Impl().foo()
+    Impl().<!INVISIBLE_REFERENCE!>packagePrivateFoo<!>()
+}

compiler/testData/diagnostics/tests/visibility/notOverridingPackagePrivate.kt

@@ -0,0 +1,23 @@
+// FILE: base/Base.java
+package base;
+
+public abstract class Base {
+    public void foo() {
+        packagePrivateFoo();
+    }
+
+    /* package-private */ void packagePrivateFoo() {};
+}
+
+// FILE: Impl.kt
+package impl
+import base.*
+
+class Impl : Base() {
+    fun packagePrivateFoo() { /*not an override*/ }
+}
+
+fun foo() {
+    Impl().foo()
+    Impl().packagePrivateFoo()
+}

compiler/testData/diagnostics/tests/visibility/notOverridingPackagePrivate.txt

@@ -0,0 +1,26 @@
+package
+
+package base {
+
+    public abstract class Base {
+        public constructor Base()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open fun foo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public/*package*/ open fun packagePrivateFoo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+package impl {
+    public fun foo(): kotlin.Unit
+
+    public final class Impl : base.Base {
+        public constructor Impl()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final fun packagePrivateFoo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}