JVM/JVM_IR: fix mapping of KClass in annotation classes

* JVM incorrectly mapped T<KClass<...>> to T<Class<...>> because the
   annotation-ness of the type mapping mode was inherited one level
   down into a generic signature independent of T

 * JVM_IR was even worse as it did not use VALUE_FOR_ANNOTATION at all,
   mapping T<T<KClass<...>> to T<T<Class<...>> as well.

The correct behavior is to map KClass to Class only at top level or as
an argument of Array.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/IrTypeMapper.kt

@@ -137,7 +137,7 @@ class IrTypeMapper(private val context: JvmBackendContext) : KotlinTypeMapperBas
                     arrayElementType = AsmTypes.OBJECT_TYPE
                     sw?.writeClass(arrayElementType)
                 } else {
-                    arrayElementType = mapType(memberType, mode.toGenericArgumentMode(variance), sw)
+                    arrayElementType = mapType(memberType, mode.toGenericArgumentMode(variance, ofArray = true), sw)
                 }
                 sw?.writeArrayEnd()
 

compiler/testData/writeSignature/annotations/kArrayClassOfKClass.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 import kotlin.reflect.KClass
 
 annotation class Ann(val arg: Array<out KClass<out KClass<*>>>)

compiler/testData/writeSignature/annotations/kClassOfKClass.kt

@@ -0,0 +1,7 @@
+import kotlin.reflect.KClass
+
+annotation class Ann(val arg: KClass<out KClass<*>>)
+
+// method: Ann::arg
+// jvm signature:     ()Ljava/lang/Class;
+// generic signature: ()Ljava/lang/Class<+Lkotlin/reflect/KClass<*>;>;

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrWriteSignatureTestGenerated.java

@@ -170,6 +170,11 @@ public class IrWriteSignatureTestGenerated extends AbstractIrWriteSignatureTest
         public void testKClassInt() throws Exception {
             runTest("compiler/testData/writeSignature/annotations/kClassInt.kt");
         }
+
+        @TestMetadata("kClassOfKClass.kt")
+        public void testKClassOfKClass() throws Exception {
+            runTest("compiler/testData/writeSignature/annotations/kClassOfKClass.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/writeSignature/callableReference")

compiler/tests/org/jetbrains/kotlin/jvm/compiler/WriteSignatureTestGenerated.java

@@ -169,6 +169,11 @@ public class WriteSignatureTestGenerated extends AbstractWriteSignatureTest {
         public void testKClassInt() throws Exception {
             runTest("compiler/testData/writeSignature/annotations/kClassInt.kt");
         }
+
+        @TestMetadata("kClassOfKClass.kt")
+        public void testKClassOfKClass() throws Exception {
+            runTest("compiler/testData/writeSignature/annotations/kClassOfKClass.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/writeSignature/callableReference")

core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/TypeMappingMode.kt

@@ -68,7 +68,7 @@ class TypeMappingMode private constructor(
         )
 
         /**
-         * kotlin.reflect.KClass mapped to java.lang.Class
+         * kotlin.reflect.KClass mapped to java.lang.Class when at top level or in an array;
          * primitive types and inline class types are not boxed because types in annotations cannot be nullable
          * Other types mapped as DEFAULT
          */
@@ -77,7 +77,7 @@ class TypeMappingMode private constructor(
             isForAnnotationParameter = true,
             needPrimitiveBoxing = false,
             needInlineClassWrapping = false,
-            genericArgumentMode = TypeMappingMode(isForAnnotationParameter = true, genericArgumentMode = GENERIC_ARGUMENT)
+            genericArgumentMode = GENERIC_ARGUMENT
         )
 
 
@@ -89,48 +89,37 @@ class TypeMappingMode private constructor(
         @JvmStatic
         fun getOptimalModeForValueParameter(
             type: KotlinType
-        ) = getOptimalModeForSignaturePart(type, isForAnnotationParameter = false, canBeUsedInSupertypePosition = true)
+        ) = getOptimalModeForSignaturePart(type, canBeUsedInSupertypePosition = true)
 
         @JvmStatic
         fun getOptimalModeForReturnType(
             type: KotlinType,
             isAnnotationMethod: Boolean
-        ) = getOptimalModeForSignaturePart(type, isForAnnotationParameter = isAnnotationMethod, canBeUsedInSupertypePosition = false)
+        ) = if (isAnnotationMethod) VALUE_FOR_ANNOTATION else getOptimalModeForSignaturePart(type, canBeUsedInSupertypePosition = false)
 
-        private fun getOptimalModeForSignaturePart(
-            type: KotlinType,
-            isForAnnotationParameter: Boolean,
-            canBeUsedInSupertypePosition: Boolean
-        ): TypeMappingMode {
+        private fun getOptimalModeForSignaturePart(type: KotlinType, canBeUsedInSupertypePosition: Boolean): TypeMappingMode {
             if (type.arguments.isEmpty()) return DEFAULT
 
             if (type.isInlineClassType() && shouldUseUnderlyingType(type)) {
                 val underlyingType = computeUnderlyingType(type)
                 if (underlyingType != null) {
-                    return getOptimalModeForSignaturePart(
-                        underlyingType, isForAnnotationParameter, canBeUsedInSupertypePosition
-                    ).dontWrapInlineClassesMode()
+                    return getOptimalModeForSignaturePart(underlyingType, canBeUsedInSupertypePosition).dontWrapInlineClassesMode()
                 }
             }
 
             val contravariantArgumentMode =
                 if (!canBeUsedInSupertypePosition)
-                    TypeMappingMode(
-                        isForAnnotationParameter = isForAnnotationParameter,
-                        skipDeclarationSiteWildcards = false,
-                        skipDeclarationSiteWildcardsIfPossible = true
-                    )
+                    TypeMappingMode(skipDeclarationSiteWildcards = false, skipDeclarationSiteWildcardsIfPossible = true)
                 else
                     null
 
             val invariantArgumentMode =
                 if (canBeUsedInSupertypePosition)
-                    getOptimalModeForSignaturePart(type, isForAnnotationParameter, canBeUsedInSupertypePosition = false)
+                    getOptimalModeForSignaturePart(type, canBeUsedInSupertypePosition = false)
                 else
                     null
 
             return TypeMappingMode(
-                isForAnnotationParameter = isForAnnotationParameter,
                 skipDeclarationSiteWildcards = !canBeUsedInSupertypePosition,
                 skipDeclarationSiteWildcardsIfPossible = true,
                 genericContravariantArgumentMode = contravariantArgumentMode,
@@ -153,8 +142,8 @@ class TypeMappingMode private constructor(
         )
     }
 
-    fun toGenericArgumentMode(effectiveVariance: Variance): TypeMappingMode =
-        when (effectiveVariance) {
+    fun toGenericArgumentMode(effectiveVariance: Variance, ofArray: Boolean = false): TypeMappingMode =
+        if (ofArray && isForAnnotationParameter) this else when (effectiveVariance) {
             Variance.IN_VARIANCE -> genericContravariantArgumentMode ?: this
             Variance.INVARIANT -> genericInvariantArgumentMode ?: this
             else -> genericArgumentMode ?: this

core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/typeSignatureMapping.kt

@@ -121,8 +121,8 @@ fun <T : Any> mapType(
                 descriptorTypeWriter?.writeArrayType()
 
                 arrayElementType = mapType(
-                    memberType, factory, mode.toGenericArgumentMode(memberProjection.projectionKind), typeMappingConfiguration,
-                    descriptorTypeWriter, writeGenericType
+                    memberType, factory, mode.toGenericArgumentMode(memberProjection.projectionKind, ofArray = true),
+                    typeMappingConfiguration, descriptorTypeWriter, writeGenericType
                 )
 
                 descriptorTypeWriter?.writeArrayEnd()