IC Mangling: Correctly mangle functions with generic return type

if the type's parent is inline class.
 #KT-43050 Fixed
 #KT-26130 Fixed
 #KT-32384 Fixed

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/inlineclasses/InlineClassAbi.kt

@@ -132,7 +132,7 @@ object InlineClassAbi {
     private fun IrType.asInfoForMangling(): InfoForMangling =
         InfoForMangling(
             erasedUpperBound.fqNameWhenAvailable!!.toUnsafe(),
-            isInline = getClass()?.isInline == true,
+            isInline = erasedUpperBound.isInline,
             isNullable = isNullable()
         )
 

compiler/testData/codegen/bytecodeListing/inlineClasses/genericChild.kt

@@ -0,0 +1,8 @@
+inline class X(val x: Any?)
+
+interface IFoo<out T : X?> {
+    fun foo(): T
+}
+
+fun <T : X> foo(x: T) {}
+

compiler/testData/codegen/bytecodeListing/inlineClasses/genericChild.txt

@@ -0,0 +1,30 @@
+@kotlin.Metadata
+public final class GenericChildKt {
+    // source: 'genericChild.kt'
+    public final static method foo-p_PkZps(@org.jetbrains.annotations.NotNull p0: java.lang.Object): void
+}
+
+@kotlin.Metadata
+public interface IFoo {
+    // source: 'genericChild.kt'
+    public abstract method foo-HezMcGQ(): X
+}
+
+@kotlin.jvm.JvmInline
+@kotlin.Metadata
+public final class X {
+    // source: 'genericChild.kt'
+    private final @org.jetbrains.annotations.Nullable field x: java.lang.Object
+    private synthetic method <init>(p0: java.lang.Object): void
+    public synthetic final static method box-impl(p0: java.lang.Object): X
+    public static @org.jetbrains.annotations.NotNull method constructor-impl(@org.jetbrains.annotations.Nullable p0: java.lang.Object): java.lang.Object
+    public method equals(p0: java.lang.Object): boolean
+    public static method equals-impl(p0: java.lang.Object, p1: java.lang.Object): boolean
+    public final static method equals-impl0(p0: java.lang.Object, p1: java.lang.Object): boolean
+    public final @org.jetbrains.annotations.Nullable method getX(): java.lang.Object
+    public method hashCode(): int
+    public static method hashCode-impl(p0: java.lang.Object): int
+    public method toString(): java.lang.String
+    public static method toString-impl(p0: java.lang.Object): java.lang.String
+    public synthetic final method unbox-impl(): java.lang.Object
+}

compiler/tests-gen/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java

@@ -1007,6 +1007,11 @@ public class BytecodeListingTestGenerated extends AbstractBytecodeListingTest {
             runTest("compiler/testData/codegen/bytecodeListing/inlineClasses/defaultInterfaceMethodsInInlineClass.kt");
         }
 
+        @TestMetadata("genericChild.kt")
+        public void testGenericChild() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeListing/inlineClasses/genericChild.kt");
+        }
+
         @TestMetadata("inlineCharSequence.kt")
         public void testInlineCharSequence() throws Exception {
             runTest("compiler/testData/codegen/bytecodeListing/inlineClasses/inlineCharSequence.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -13489,11 +13489,6 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/inlineClassWithCustomEquals.kt");
         }
 
-        @TestMetadata("multifileClass.kt")
-        public void ignoreMultifileClass() throws Exception {
-            runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
-        }
-
         @TestMetadata("simpleSecondaryConstructor.kt")
         public void ignoreSimpleSecondaryConstructor() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/simpleSecondaryConstructor.kt");
@@ -14142,6 +14137,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/mappingOfBoxedFlexibleInlineClassType.kt");
         }
 
+        @TestMetadata("multifileClass.kt")
+        public void testMultifileClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
+        }
+
         @TestMetadata("nestedInlineClass.kt")
         public void testNestedInlineClass() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/ir/IrBytecodeListingTestGenerated.java

@@ -1007,6 +1007,11 @@ public class IrBytecodeListingTestGenerated extends AbstractIrBytecodeListingTes
             runTest("compiler/testData/codegen/bytecodeListing/inlineClasses/defaultInterfaceMethodsInInlineClass.kt");
         }
 
+        @TestMetadata("genericChild.kt")
+        public void testGenericChild() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeListing/inlineClasses/genericChild.kt");
+        }
+
         @TestMetadata("inlineCharSequence.kt")
         public void testInlineCharSequence() throws Exception {
             runTest("compiler/testData/codegen/bytecodeListing/inlineClasses/inlineCharSequence.kt");

core/descriptors.jvm/src/org/jetbrains/kotlin/resolve/jvm/inlineClassManglingRules.kt

@@ -35,7 +35,7 @@ fun requiresFunctionNameManglingForParameterTypes(descriptor: CallableMemberDesc
 fun requiresFunctionNameManglingForReturnType(descriptor: CallableMemberDescriptor): Boolean {
     if (descriptor.containingDeclaration !is ClassDescriptor) return false
     val returnType = descriptor.returnType ?: return false
-    return returnType.isInlineClassType()
+    return returnType.isInlineClassType() || returnType.isTypeParameterWithUpperBoundThatRequiresMangling()
 }
 
 fun DeclarationDescriptor.isInlineClassThatRequiresMangling(): Boolean =