Fix for KT-13890: IllegalAccessError when invoking protected method with default arguments

#KT-13890 Fixed

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

@@ -845,14 +845,13 @@ public class FunctionCodegen {
             return;
         }
 
-        int flags = getVisibilityAccessFlag(functionDescriptor) |
-                    getDeprecatedAccessFlag(functionDescriptor) |
-                    ACC_SYNTHETIC;
+        // $default methods are never private to be accessible from other class files (e.g. inner) without the need of synthetic accessors
+        // $default methods are never protected to be accessible from subclass nested classes
+        int visibilityFlag = Visibilities.isPrivate(functionDescriptor.getVisibility()) ? AsmUtil.NO_FLAG_PACKAGE_PRIVATE : Opcodes.ACC_PUBLIC;
+        int flags =  visibilityFlag | getDeprecatedAccessFlag(functionDescriptor) | ACC_SYNTHETIC;
         if (!(functionDescriptor instanceof ConstructorDescriptor)) {
             flags |= ACC_STATIC | ACC_BRIDGE;
         }
-        // $default methods are never private to be accessible from other class files (e.g. inner) without the need of synthetic accessors
-        flags &= ~ACC_PRIVATE;
 
         Method defaultMethod = typeMapper.mapDefaultMethod(functionDescriptor, kind);
 

compiler/testData/codegen/box/defaultArguments/protected.kt

@@ -0,0 +1,23 @@
+// FILE: Foo.kt
+
+package foo
+
+open class Foo() {
+    protected fun foo(value: Boolean = false) = if (!value) "OK" else "fail5"
+}
+
+// FILE: Bar.kt
+
+package bar
+
+import foo.Foo
+
+class Bar() : Foo() {
+    fun execute(): String {
+        return { foo() } ()
+    }
+}
+
+fun box(): String {
+    return Bar().execute()
+}

compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -5113,6 +5113,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("protected.kt")
+        public void testProtected() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/defaultArguments/protected.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");

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

@@ -5113,6 +5113,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("protected.kt")
+        public void testProtected() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/defaultArguments/protected.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");