Report error on missed specialization in compatibility mode

#KT-39603 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/ClassBodyCodegen.java

@@ -39,6 +39,8 @@ import static org.jetbrains.kotlin.codegen.binding.CodegenBinding.enumEntryNeedS
 import static org.jetbrains.kotlin.resolve.DescriptorToSourceUtils.descriptorToDeclaration;
 import static org.jetbrains.kotlin.resolve.jvm.AsmTypes.OBJECT_TYPE;
 import static org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOriginKind.CLASS_MEMBER_DELEGATION_TO_DEFAULT_IMPL;
+import static org.jetbrains.kotlin.util.DeclarationUtilKt.findImplementationFromInterface;
+import static org.jetbrains.kotlin.util.DeclarationUtilKt.findInterfaceImplementation;
 
 public abstract class ClassBodyCodegen extends MemberCodegen<KtPureClassOrObject> {
     @NotNull
@@ -125,7 +127,7 @@ public abstract class ClassBodyCodegen extends MemberCodegen<KtPureClassOrObject
         for (DeclarationDescriptor memberDescriptor : DescriptorUtils.getAllDescriptors(descriptor.getDefaultType().getMemberScope())) {
             if (memberDescriptor instanceof CallableMemberDescriptor) {
                 CallableMemberDescriptor member = (CallableMemberDescriptor) memberDescriptor;
-                if (!member.getKind().isReal() && ImplKt.findInterfaceImplementation(member) == null) {
+                if (!member.getKind().isReal() && findInterfaceImplementation(member) == null) {
                     if (member instanceof FunctionDescriptor) {
                         functionCodegen.generateBridges((FunctionDescriptor) member);
                     }
@@ -242,7 +244,7 @@ public abstract class ClassBodyCodegen extends MemberCodegen<KtPureClassOrObject
         }
 
         CallableMemberDescriptor actualImplementation =
-                interfaceFun.getKind().isReal() ? interfaceFun : ImplKt.findImplementationFromInterface(interfaceFun);
+                interfaceFun.getKind().isReal() ? interfaceFun : findImplementationFromInterface(interfaceFun);
         assert actualImplementation != null : "Can't find actual implementation for " + interfaceFun;
         if (JvmAnnotationUtilKt.isCallableMemberCompiledToJvmDefault(actualImplementation, state.getJvmDefaultMode())) {
             return;

compiler/backend/src/org/jetbrains/kotlin/codegen/FunctionCodegen.java

@@ -608,7 +608,7 @@ public class FunctionCodegen {
                     true, mv,
                     method.getAsmMethod(),
                     method.getOwner().getInternalName(),
-                    true);
+                    true, signature.getReturnType());
             methodEnd = new Label();
         }
         else {
@@ -850,7 +850,8 @@ public class FunctionCodegen {
             @NotNull Method asmMethod,
             @NotNull String classToDelegateTo,
             int opcode,
-            boolean isInterface
+            boolean isInterface,
+            @NotNull Type returnType
     ) {
         InstructionAdapter iv = new InstructionAdapter(mv);
         Type[] argTypes = asmMethod.getArgumentTypes();
@@ -872,7 +873,8 @@ public class FunctionCodegen {
             paramIndex += argType.getSize();
         }
         iv.visitMethodInsn(opcode, classToDelegateTo, asmMethod.getName(), asmMethod.getDescriptor(), isInterface);
-        iv.areturn(asmMethod.getReturnType());
+        StackValue.onStack(asmMethod.getReturnType()).coerceTo(returnType, null, iv);
+        iv.areturn(returnType);
     }
 
     private static void generateDelegateToStaticErasedVersion(
@@ -911,7 +913,19 @@ public class FunctionCodegen {
             @NotNull String classToDelegateTo,
             boolean isInterfaceMethodCall
     ) {
-        generateDelegateToMethodBody(isStatic ? 0 : 1, mv, asmMethod, classToDelegateTo, Opcodes.INVOKESTATIC, isInterfaceMethodCall);
+        generateDelegateToStaticMethodBody(isStatic, mv, asmMethod, classToDelegateTo, isInterfaceMethodCall, asmMethod.getReturnType());
+    }
+
+
+    private static void generateDelegateToStaticMethodBody(
+            boolean isStatic,
+            @NotNull MethodVisitor mv,
+            @NotNull Method asmMethod,
+            @NotNull String classToDelegateTo,
+            boolean isInterfaceMethodCall,
+            @NotNull Type returnType
+    ) {
+        generateDelegateToMethodBody(isStatic ? 0 : 1, mv, asmMethod, classToDelegateTo, Opcodes.INVOKESTATIC, isInterfaceMethodCall, returnType);
     }
 
     private static boolean needIndexForVar(JvmMethodParameterKind kind) {

compiler/backend/src/org/jetbrains/kotlin/codegen/InterfaceImplBodyCodegen.kt

@@ -17,8 +17,7 @@
 package org.jetbrains.kotlin.codegen
 
 import com.intellij.util.ArrayUtil
-import org.jetbrains.kotlin.backend.common.bridges.findImplementationFromInterface
-import org.jetbrains.kotlin.backend.common.bridges.firstSuperMethodFromKotlin
+import org.jetbrains.kotlin.util.findImplementationFromInterface
 import org.jetbrains.kotlin.codegen.context.ClassContext
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.codegen.state.JvmMethodExceptionTypes
@@ -29,6 +28,7 @@ import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOrigin
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOriginKind
 import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmMethodSignature
+import org.jetbrains.kotlin.util.firstSuperMethodFromKotlin
 import org.jetbrains.org.objectweb.asm.MethodVisitor
 import org.jetbrains.org.objectweb.asm.Opcodes.*
 

compiler/backend/src/org/jetbrains/kotlin/codegen/JvmBridgesImpl.kt

@@ -16,6 +16,8 @@ import org.jetbrains.kotlin.load.java.descriptors.JavaForKotlinOverridePropertyD
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.jvm.annotations.isCompiledToJvmDefault
 import org.jetbrains.kotlin.resolve.jvm.annotations.hasPlatformDependentAnnotation
+import org.jetbrains.kotlin.util.findImplementationFromInterface
+import org.jetbrains.kotlin.util.findInterfaceImplementation
 
 class DescriptorBasedFunctionHandleForJvm(
     descriptor: FunctionDescriptor,