JVM.IR. Add assertions for JVM defaults checks

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/annotations/jvmAnnotationUtil.kt

@@ -53,6 +53,11 @@ fun CallableMemberDescriptor.isCompiledToJvmDefaultIfNoAbstract(jvmDefault: JvmD
 
     val clazz = directMember.containingDeclaration
 
+//  TODO add checks after fixes in diagnostics
+//    assert(this.kind.isReal && isInterface(clazz) && modality != Modality.ABSTRACT) {
+//        "`isCompiledToJvmDefault` should be called on non-fakeoverrides and non-abstract methods from interfaces $this"
+//    }
+
     if (directMember.annotations.hasAnnotation(JVM_DEFAULT_FQ_NAME)) return true
     if (clazz !is DeserializedClassDescriptor) return jvmDefault.forAllMethodsWithBody
     return JvmProtoBufUtil.isNewPlaceForBodyGeneration(clazz.classProto)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/ir/IrUtils.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.backend.jvm.ir
 
+import org.jetbrains.kotlin.backend.common.ir.ir2string
 import org.jetbrains.kotlin.backend.common.lower.IrLoweringContext
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
@@ -147,10 +148,17 @@ fun IrDeclaration.getJvmNameFromAnnotation(): String? {
 val IrFunction.propertyIfAccessor: IrDeclaration
     get() = (this as? IrSimpleFunction)?.correspondingPropertySymbol?.owner ?: this
 
-fun IrFunction.isCompiledToJvmDefault(jvmDefaultMode: JvmDefaultMode): Boolean {
+fun IrFunction.isSimpleFunctionCompiledToJvmDefault(jvmDefaultMode: JvmDefaultMode): Boolean {
+    return (this as? IrSimpleFunction)?.isCompiledToJvmDefault(jvmDefaultMode) == true
+}
+
+fun IrSimpleFunction.isCompiledToJvmDefault(jvmDefaultMode: JvmDefaultMode): Boolean {
+    assert(!isFakeOverride && parentAsClass.isInterface && modality != Modality.ABSTRACT) {
+        "`isCompiledToJvmDefault` should be called on non-fakeoverrides and non-abstract methods from interfaces ${ir2string(this)}"
+    }
     if (hasJvmDefault()) return true
     val parentDescriptor = propertyIfAccessor.parentAsClass.descriptor
-    if (parentDescriptor !is DeserializedClassDescriptor) return jvmDefaultMode.forAllMehtodsWithBody
+    if (parentDescriptor !is DeserializedClassDescriptor) return jvmDefaultMode.forAllMethodsWithBody
     return JvmProtoBufUtil.isNewPlaceForBodyGeneration(parentDescriptor.classProto)
 }
 
@@ -286,10 +294,13 @@ fun IrFunctionAccessExpression.copyFromWithPlaceholderTypeArguments(existingCall
 
 // Check whether a function maps to an abstract method.
 // For non-interface methods or interface methods coming from Java the modality is correct. Kotlin interface methods
-// are abstract unless they are annotated with @JvmDefault or @PlatformDependent or they override a method with
-// such an annotation.
-fun IrSimpleFunction.isJvmAbstract(jvmDefaultMode: JvmDefaultMode): Boolean = (modality == Modality.ABSTRACT) ||
-        (parentAsClass.isJvmInterface && resolveFakeOverride()?.run { !isCompiledToJvmDefault(jvmDefaultMode) && !hasPlatformDependent() } ?: true)
+// are abstract unless they are annotated @PlatformDependent or compiled to JVM default (with @JvmDefault annotation or without)
+// or they override such method.
+fun IrSimpleFunction.isJvmAbstract(jvmDefaultMode: JvmDefaultMode): Boolean {
+    if (modality == Modality.ABSTRACT) return true
+    if (!parentAsClass.isJvmInterface) return false
+    return resolveFakeOverride()?.run { !isCompiledToJvmDefault(jvmDefaultMode) && !hasPlatformDependent() } != false
+}
 
 fun firstSuperMethodFromKotlin(
     override: IrSimpleFunction,

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

@@ -153,7 +153,7 @@ private class InterfaceDefaultCallsLowering(val context: JvmBackendContext) : Ir
 
         if (!callee.hasInterfaceParent() ||
             callee.origin != IrDeclarationOrigin.FUNCTION_FOR_DEFAULT_PARAMETER ||
-            callee.isCompiledToJvmDefault(context.state.jvmDefaultMode)
+            callee.isSimpleFunctionCompiledToJvmDefault(context.state.jvmDefaultMode)
         ) {
             return super.visitCall(expression)
         }
@@ -171,14 +171,19 @@ private class InterfaceDefaultCallsLowering(val context: JvmBackendContext) : Ir
     }
 }
 
-private fun IrSimpleFunction.isDefinitelyNotDefaultImplsMethod(jvmDefaultMode: JvmDefaultMode) =
-    resolveFakeOverride()?.origin == IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB ||
-            origin == IrDeclarationOrigin.FUNCTION_FOR_DEFAULT_PARAMETER ||
+private fun IrSimpleFunction.isDefinitelyNotDefaultImplsMethod(jvmDefaultMode: JvmDefaultMode): Boolean {
+    if (resolveFakeOverride()?.run {
+            origin == IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB || isCompiledToJvmDefault(
+                jvmDefaultMode
+            )
+        } != false) return true
+
+    return origin == IrDeclarationOrigin.FUNCTION_FOR_DEFAULT_PARAMETER ||
             hasAnnotation(PLATFORM_DEPENDENT_ANNOTATION_FQ_NAME) ||
-            isCompiledToJvmDefault(jvmDefaultMode) ||
             (name.asString() == "clone" &&
                     parent.safeAs<IrClass>()?.fqNameWhenAvailable?.asString() == "kotlin.Cloneable" &&
                     valueParameters.isEmpty())
+}
 
 internal val interfaceObjectCallsPhase = makeIrFilePhase(
     lowering = ::InterfaceObjectCallsLowering,

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

@@ -23,7 +23,6 @@ import org.jetbrains.kotlin.ir.expressions.IrReturn
 import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrLocalDelegatedPropertySymbol
-import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
@@ -78,7 +77,7 @@ internal class InterfaceLowering(val context: JvmBackendContext) : IrElementTran
                  *    - the implementation is private, or belongs to java.lang.Object,
                  *      or is a stub for function with default parameters ($default)
                  *    - we're in -Xjvm-default=compatibility|all-compatibility mode, in which case we go via
-                 *      accessors on the parent class rather than the DefaultImpls if inherited method compiled to JVM default
+                 *      accessors on the parent class rather than the DefaultImpls if inherited method is compiled to JVM default
                  *    - we're in -Xjvm-default=enable|all mode, and we have that default implementation,
                  *      in which case we simply leave it.
                  *

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

@@ -493,7 +493,7 @@ internal class SyntheticAccessorLowering(val context: JvmBackendContext) : IrEle
         }
     }
 
-    private fun IrFunction.accessorName(superQualifier: IrClassSymbol?): Name {
+    private fun IrSimpleFunction.accessorName(superQualifier: IrClassSymbol?): Name {
         val jvmName = context.methodSignatureMapper.mapFunctionName(this)
         val suffix = when {
             // Accessors for top level functions never need a suffix.
@@ -501,7 +501,7 @@ internal class SyntheticAccessorLowering(val context: JvmBackendContext) : IrEle
 
             // The only function accessors placed on interfaces are for private functions and JvmDefault implementations.
             // The two cannot clash.
-            parentAsClass.isJvmInterface -> if (!Visibilities.isPrivate(visibility) && isCompiledToJvmDefault(context.state.jvmDefaultMode)) "\$jd" else ""
+            parentAsClass.isJvmInterface -> if (!Visibilities.isPrivate(visibility)) "\$jd" else ""
 
             // Accessor for _s_uper-qualified call
             superQualifier != null -> "\$s" + superQualifier.descriptor.syntheticAccessorToSuperSuffix()