KT-11943 Do not use intrinsic 'java' property if receiver type is not acceptable

compiler/backend/src/org/jetbrains/kotlin/codegen/intrinsics/KClassJavaProperty.kt

@@ -16,10 +16,12 @@
 
 package org.jetbrains.kotlin.codegen.intrinsics
 
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.codegen.AsmUtil
 import org.jetbrains.kotlin.codegen.ExpressionCodegen
 import org.jetbrains.kotlin.codegen.StackValue
 import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.psi.KtClassLiteralExpression
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
@@ -31,8 +33,8 @@ import org.jetbrains.org.objectweb.asm.commons.InstructionAdapter
 
 class KClassJavaProperty : IntrinsicPropertyGetter() {
     override fun generate(resolvedCall: ResolvedCall<*>?, codegen: ExpressionCodegen, returnType: Type, receiver: StackValue): StackValue? {
-        val extensionReceiver = resolvedCall!!.extensionReceiver!!
-        val type = extensionReceiver.type.arguments.single().type
+        val receiverType = resolvedCall!!.extensionReceiver!!.type
+        val type = getKClassTypeArgument(receiverType) ?: return null
         val asmType = codegen.state.typeMapper.mapType(type)
 
         return when {
@@ -58,6 +60,14 @@ class KClassJavaProperty : IntrinsicPropertyGetter() {
         }
     }
 
+    private fun getKClassTypeArgument(type: KotlinType): KotlinType? {
+        val typeClassifier = type.constructor.declarationDescriptor
+        return if (typeClassifier is ClassDescriptor && KotlinBuiltIns.isKClass(typeClassifier))
+            type.arguments.singleOrNull()?.type
+        else
+            null
+    }
+
     private fun isReifiedTypeParameter(type: KotlinType): Boolean {
         val typeDescriptor = type.constructor.declarationDescriptor
         return typeDescriptor is TypeParameterDescriptor && typeDescriptor.isReified

compiler/testData/codegen/box/reflection/javaProperties/kt11943.kt

@@ -0,0 +1,16 @@
+// WITH_REFLECT
+
+import kotlin.reflect.KClass
+
+val <T : KClass<*>> T.myjava1: Class<*>
+    get() = java
+
+val <E : Any, T : KClass<E>> T.myjava2: Class<E>
+    get() = java
+
+class O
+class K
+
+fun box(): String =
+        O::class.myjava1.getSimpleName() + K::class.myjava2.getSimpleName()
+

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -11285,6 +11285,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/javaProperties/javaReified.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("kt11943.kt")
+            public void testKt11943() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/javaProperties/kt11943.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("compiler/testData/codegen/box/reflection/kClassInAnnotation")