NoArg: Fix IllegalAccessError on instantiating sealed class child via Java reflection (KT-18245)

plugins/noarg/noarg-cli/src/NoArgExpressionCodegenExtension.kt

@@ -44,15 +44,24 @@ class NoArgExpressionCodegenExtension(val invokeInitializers: Boolean = false) :
 
         val constructorDescriptor = createNoArgConstructorDescriptor(descriptor)
 
+        val isParentASealedClass = (descriptor.containingDeclaration as? ClassDescriptor)?.modality == Modality.SEALED
+
         functionCodegen.generateMethod(JvmDeclarationOrigin.NO_ORIGIN, constructorDescriptor, object: CodegenBased(state) {
             override fun doGenerateBody(codegen: ExpressionCodegen, signature: JvmMethodSignature) {
                 codegen.v.load(0, AsmTypes.OBJECT_TYPE)
-                codegen.v.visitMethodInsn(Opcodes.INVOKESPECIAL, superClassInternalName, "<init>", "()V", false)
+
+                if (isParentASealedClass) {
+                    codegen.v.aconst(null)
+                    codegen.v.visitMethodInsn(Opcodes.INVOKESPECIAL, superClassInternalName, "<init>",
+                                              "(Lkotlin/jvm/internal/DefaultConstructorMarker;)V", false)
+                }
+                else {
+                    codegen.v.visitMethodInsn(Opcodes.INVOKESPECIAL, superClassInternalName, "<init>", "()V", false)
+                }
 
                 if (invokeInitializers) {
                     generateInitializers(codegen)
                 }
-
                 codegen.v.visitInsn(Opcodes.RETURN)
             }
         })

plugins/noarg/noarg-cli/testData/box/kt18245.kt

@@ -0,0 +1,22 @@
+// WITH_RUNTIME
+
+annotation class NoArg
+
+sealed class Test {
+    abstract val test: String
+
+    @NoArg
+    data class Test1(override val test: String) : Test()
+
+    @NoArg
+    data class Test2(override val test: String) : Test()
+}
+
+fun box(): String {
+    Test::class.java.declaredConstructors.forEach { it.isAccessible = true }
+    Test.Test1::class.java.declaredConstructors.forEach { it.isAccessible = true }
+
+    val instance = Test.Test1::class.java.newInstance() // Error
+
+    return "OK"
+}

plugins/plugins-tests/tests/org/jetbrains/kotlin/noarg/BlackBoxCodegenTestForNoArgGenerated.java

@@ -48,6 +48,12 @@ public class BlackBoxCodegenTestForNoArgGenerated extends AbstractBlackBoxCodege
         doTest(fileName);
     }
 
+    @TestMetadata("kt18245.kt")
+    public void testKt18245() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("plugins/noarg/noarg-cli/testData/box/kt18245.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("kt18667.kt")
     public void testKt18667() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("plugins/noarg/noarg-cli/testData/box/kt18667.kt");