IR: check visibility when building fake overrides

This fixes the difference at least in the IR text test
testFakeOverridesForJavaNonStaticMembers. There's no fake override
created anymore for `packagePrivateMethod` in Test2.

 #KT-61366 Fixed

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/overrides/IrOverridingUtil.kt

@@ -216,12 +216,6 @@ class IrOverridingUtil(
         return trueFakeOverrides.ifEmpty { customizedFakeOverrides }
     }
 
-    private fun filterVisibleFakeOverrides(toFilter: Collection<IrOverridableMember>): Collection<IrOverridableMember> {
-        return toFilter.filter { member: IrOverridableMember ->
-            !DescriptorVisibilities.isPrivate(member.visibility) && member.visibility != DescriptorVisibilities.INVISIBLE_FAKE
-        }
-    }
-
     private fun determineModalityForFakeOverride(
         members: Collection<IrOverridableMember>,
         current: IrClass
@@ -328,7 +322,7 @@ class IrOverridingUtil(
         addedFakeOverrides: MutableList<IrOverridableMember>,
         compatibilityMode: Boolean
     ) {
-        val effectiveOverridden = filterVisibleFakeOverrides(overridables)
+        val effectiveOverridden = overridables.filter { it.isVisibleInClass(currentClass) }
 
         // The descriptor based algorithm goes further building invisible fakes here,
         // but we don't use invisible fakes in IR

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/overrides/IrVisibilityUtil.kt

@@ -5,22 +5,17 @@
 
 package org.jetbrains.kotlin.ir.overrides
 
-import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithVisibility
-import org.jetbrains.kotlin.ir.declarations.IrOverridableDeclaration
-import org.jetbrains.kotlin.ir.declarations.IrOverridableMember
-import org.jetbrains.kotlin.ir.util.parentClassOrNull
+import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
+import org.jetbrains.kotlin.descriptors.DescriptorVisibility
+import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.types.getClass
+import org.jetbrains.kotlin.ir.util.*
 
-// The contents of this file is from VisibilityUtil.kt adapted to IR.
-// TODO: The code would better be commonized for descriptors, ir and fir.
-
-fun isVisibleForOverride(
-    @Suppress("UNUSED_PARAMETER") overriding: IrOverridableMember,
-    fromSuper: IrOverridableMember
-): Boolean {
-    return !DescriptorVisibilities.isPrivate((fromSuper as IrDeclarationWithVisibility).visibility)
+fun isVisibleForOverride(overriding: IrOverridableMember, fromSuper: IrOverridableMember): Boolean {
+    return fromSuper.isVisibleInClass(overriding.parentAsClass)
 }
 
+// Based on findMemberWithMaxVisibility from VisibilityUtil.kt.
 fun findMemberWithMaxVisibility(members: Collection<IrOverridableMember>): IrOverridableMember {
     assert(members.isNotEmpty())
 
@@ -60,3 +55,25 @@ fun IrDeclarationWithVisibility.isEffectivelyPrivate(): Boolean {
         else -> true
     }
 }
+
+internal fun IrOverridableMember.isVisibleInClass(klass: IrClass): Boolean {
+    if (DescriptorVisibilities.isPrivate(visibility) || visibility == DescriptorVisibilities.INVISIBLE_FAKE) return false
+
+    // OverridingUtil.isVisibleForOverride just calls DescriptorVisibilities.isVisible here. However, we can't use descriptors. Moreover,
+    // the current member's parent has already been reassigned to the current class (in OverridingUtil, it is still the original class where
+    // the member was declared at this point). So we load the original class from the dispatch receiver.
+    val dispatchReceiver = when (this) {
+        is IrSimpleFunction -> dispatchReceiverParameter
+        is IrProperty -> getter?.dispatchReceiverParameter
+        else -> error("Unsupported member: ${render()}")
+    } ?: error("Members without dispatch receiver are not possible here: ${render()} (klass=${klass.fqNameWhenAvailable}")
+
+    // Package-private Java members are only overridable within the same package.
+    val originalClass = dispatchReceiver.type.getClass()!!
+    if (!visibility.visibleFromPackage(klass.getPackageFragment().packageFqName, originalClass.getPackageFragment().packageFqName))
+        return false
+
+    // TODO (KT-61384): also check internal.
+
+    return true
+}

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/JavaDescriptorVisibilities.java

@@ -20,6 +20,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.java.JavaVisibilities;
+import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
 
@@ -41,6 +42,11 @@ public class JavaDescriptorVisibilities {
         ) {
             return areInSamePackage(what, from);
         }
+
+        @Override
+        public boolean visibleFromPackage(@NotNull FqName fromPackage, @NotNull FqName myPackage) {
+            return fromPackage.equals(myPackage);
+        }
     };
 
     @NotNull

core/descriptors/src/org/jetbrains/kotlin/descriptors/DescriptorVisibility.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.descriptors
 
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
 
 abstract class DescriptorVisibility protected constructor() {
@@ -78,6 +79,8 @@ abstract class DescriptorVisibility protected constructor() {
 
     // Should be overloaded in Java visibilities
     fun customEffectiveVisibility(): EffectiveVisibility? = delegate.customEffectiveVisibility()
+
+    open fun visibleFromPackage(fromPackage: FqName, myPackage: FqName): Boolean = true
 }
 
 abstract class DelegatedDescriptorVisibility(override val delegate: Visibility) : DescriptorVisibility() {