FIR visibility check: support companion private members correctly

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolverParts.kt

@@ -277,7 +277,9 @@ internal object CheckVisibility : CheckerStage() {
     private fun ImplicitReceiverStack.canSeePrivateMemberOf(ownerId: ClassId): Boolean {
         for (implicitReceiverValue in receiversAsReversed()) {
             if (implicitReceiverValue !is ImplicitDispatchReceiverValue) continue
-            if (implicitReceiverValue.boundSymbol.classId == ownerId) return true
+            val boundSymbol = implicitReceiverValue.boundSymbol
+            if (boundSymbol.classId == ownerId) return true
+            if (boundSymbol is FirRegularClassSymbol && boundSymbol.fir.companionObject?.symbol?.classId == ownerId) return true
         }
         return false
     }

compiler/fir/resolve/testData/resolve/expresssions/privateVisibility.kt

@@ -8,15 +8,32 @@ private class Private {
     fun baz() {
         bar()
         Nested()
+        fromCompanion()
+        NotCompanion.<!INAPPLICABLE_CANDIDATE!>foo<!>() // hidden
     }
 
     inner class Inner {
         fun foo() {
             bar()
+            fromCompanion()
+            NotCompanion.<!INAPPLICABLE_CANDIDATE!>foo<!>() // hidden
         }
     }
 
-    private class Nested
+    private class Nested {
+        fun foo() {
+            fromCompanion()
+            NotCompanion.<!INAPPLICABLE_CANDIDATE!>foo<!>() // hidden
+        }
+    }
+
+    companion object {
+        private fun fromCompanion() {}
+    }
+
+    object NotCompanion {
+        private fun foo() {}
+    }
 }
 
 fun withLocals() {
@@ -47,6 +64,7 @@ fun test() {
 
     Private().<!INAPPLICABLE_CANDIDATE!>bar<!>() // hidden
     Private.<!INAPPLICABLE_CANDIDATE!>Nested<!>() // hidden
+    Private.<!INAPPLICABLE_CANDIDATE!>fromCompanion<!>() // hidden
 }
 
 // FILE: second.kt

compiler/fir/resolve/testData/resolve/expresssions/privateVisibility.txt

@@ -12,6 +12,8 @@ FILE: first.kt
         public final fun baz(): R|kotlin/Unit| {
             this@R|/Private|.R|/Private.bar|()
             R|/Private.Nested.Nested|()
+            this@R|/Private.Companion|.R|/Private.Companion.fromCompanion|()
+            Q|Private.NotCompanion|.<Inapplicable(HIDDEN): [/Private.NotCompanion.foo]>#()
         }
 
         public final inner class Inner : R|kotlin/Any| {
@@ -21,6 +23,8 @@ FILE: first.kt
 
             public final fun foo(): R|kotlin/Unit| {
                 this@R|/Private|.R|/Private.bar|()
+                this@R|/Private.Companion|.R|/Private.Companion.fromCompanion|()
+                Q|Private.NotCompanion|.<Inapplicable(HIDDEN): [/Private.NotCompanion.foo]>#()
             }
 
         }
@@ -30,6 +34,31 @@ FILE: first.kt
                 super<R|kotlin/Any|>()
             }
 
+            public final fun foo(): R|kotlin/Unit| {
+                this@R|/Private.Companion|.R|/Private.Companion.fromCompanion|()
+                Q|Private.NotCompanion|.<Inapplicable(HIDDEN): [/Private.NotCompanion.foo]>#()
+            }
+
+        }
+
+        public final companion object Companion : R|kotlin/Any| {
+            private constructor(): R|Private.Companion| {
+                super<R|kotlin/Any|>()
+            }
+
+            private final fun fromCompanion(): R|kotlin/Unit| {
+            }
+
+        }
+
+        public final object NotCompanion : R|kotlin/Any| {
+            private constructor(): R|Private.NotCompanion| {
+                super<R|kotlin/Any|>()
+            }
+
+            private final fun foo(): R|kotlin/Unit| {
+            }
+
         }
 
     }
@@ -68,6 +97,7 @@ FILE: first.kt
         R|/Private.Private|().R|/Private.Inner.Inner|()
         R|/Private.Private|().<Inapplicable(HIDDEN): [/Private.bar]>#()
         Q|Private|.<Inapplicable(HIDDEN): [/Private.Nested.Nested]>#()
+        Q|Private|.<Inapplicable(HIDDEN): [/Private.Companion.fromCompanion]>#()
     }
 FILE: second.kt
     public final fun secondTest(): R|kotlin/Unit| {