KT-36973 Keep private default interface members private

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -27022,6 +27022,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/traits/kt3579_2.kt");
         }
 
+        @TestMetadata("kt36973.kt")
+        public void testKt36973() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/kt36973.kt");
+        }
+
         @TestMetadata("kt5393.kt")
         public void testKt5393() throws Exception {
             runTest("compiler/testData/codegen/box/traits/kt5393.kt");

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/descriptors/JvmDeclarationFactory.kt

@@ -233,11 +233,10 @@ class JvmDeclarationFactory(
                 // Old backend doesn't generate ACC_FINAL on DefaultImpls methods.
                 modality = Modality.OPEN,
 
-                // Interface functions are always public, with one exception: clone in Cloneable, which is protected. However, Cloneable
+                // Interface functions are public or private, with one exception: clone in Cloneable, which is protected.
-                // has no DefaultImpls, so this merely replicates the incorrect behavior of the old backend. We should rather not generate
+                // However, Cloneable has no DefaultImpls, so this merely replicates the incorrect behavior of the old backend.
-                // a bridge to clone when interface inherits from Cloneable at all. Below, we force everything, including those bridges,
+                // We should rather not generate a bridge to clone when interface inherits from Cloneable at all.
-                // to be public so that we won't try to generate synthetic accessor for them.
+                visibility = if (interfaceFun.visibility == Visibilities.PRIVATE) Visibilities.PRIVATE else Visibilities.PUBLIC,
-                visibility = Visibilities.PUBLIC,
 
                 typeParametersFromContext = parent.typeParameters
             )

compiler/testData/codegen/box/traits/kt36973.kt

@@ -0,0 +1,15 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// FILE: kt36973.kt
+import other.*
+
+class C : IFoo
+
+fun box() = C().foo()()
+
+// FILE: IFoo.kt
+package other
+
+interface IFoo {
+    fun foo() = { bar() }
+    private fun bar() = "OK"
+}

compiler/testData/codegen/bytecodeListing/privateDefaultImpls.kt

@@ -0,0 +1,4 @@
+interface A {
+    private fun foo() {}
+    private val x get() = 1
+}

compiler/testData/codegen/bytecodeListing/privateDefaultImpls.txt

@@ -0,0 +1,11 @@
+@kotlin.Metadata
+public final class A$DefaultImpls {
+    inner class A$DefaultImpls
+    private static method foo(p0: A): void
+    private static method getX(p0: A): int
+}
+
+@kotlin.Metadata
+public interface A {
+    inner class A$DefaultImpls
+}

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

@@ -28538,6 +28538,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/traits/kt3579_2.kt");
         }
 
+        @TestMetadata("kt36973.kt")
+        public void testKt36973() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/kt36973.kt");
+        }
+
         @TestMetadata("kt5393.kt")
         public void testKt5393() throws Exception {
             runTest("compiler/testData/codegen/box/traits/kt5393.kt");

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

@@ -104,6 +104,11 @@ public class BytecodeListingTestGenerated extends AbstractBytecodeListingTest {
         runTest("compiler/testData/codegen/bytecodeListing/platformTypes.kt");
     }
 
+    @TestMetadata("privateDefaultImpls.kt")
+    public void testPrivateDefaultImpls() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/privateDefaultImpls.kt");
+    }
+
     @TestMetadata("privateDefaultSetter.kt")
     public void testPrivateDefaultSetter() throws Exception {
         runTest("compiler/testData/codegen/bytecodeListing/privateDefaultSetter.kt");

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

@@ -27355,6 +27355,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/traits/kt3579_2.kt");
         }
 
+        @TestMetadata("kt36973.kt")
+        public void testKt36973() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/kt36973.kt");
+        }
+
         @TestMetadata("kt5393.kt")
         public void testKt5393() throws Exception {
             runTest("compiler/testData/codegen/box/traits/kt5393.kt");

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

@@ -27022,6 +27022,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/traits/kt3579_2.kt");
         }
 
+        @TestMetadata("kt36973.kt")
+        public void testKt36973() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/kt36973.kt");
+        }
+
         @TestMetadata("kt5393.kt")
         public void testKt5393() throws Exception {
             runTest("compiler/testData/codegen/box/traits/kt5393.kt");

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

@@ -104,6 +104,11 @@ public class IrBytecodeListingTestGenerated extends AbstractIrBytecodeListingTes
         runTest("compiler/testData/codegen/bytecodeListing/platformTypes.kt");
     }
 
+    @TestMetadata("privateDefaultImpls.kt")
+    public void testPrivateDefaultImpls() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/privateDefaultImpls.kt");
+    }
+
     @TestMetadata("privateDefaultSetter.kt")
     public void testPrivateDefaultSetter() throws Exception {
         runTest("compiler/testData/codegen/bytecodeListing/privateDefaultSetter.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -21923,6 +21923,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/traits/kt3579_2.kt");
         }
 
+        @TestMetadata("kt36973.kt")
+        public void testKt36973() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/kt36973.kt");
+        }
+
         @TestMetadata("kt5393.kt")
         public void testKt5393() throws Exception {
             runTest("compiler/testData/codegen/box/traits/kt5393.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -21983,6 +21983,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/traits/kt3579_2.kt");
         }
 
+        @TestMetadata("kt36973.kt")
+        public void testKt36973() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/kt36973.kt");
+        }
+
         @TestMetadata("kt5393.kt")
         public void testKt5393() throws Exception {
             runTest("compiler/testData/codegen/box/traits/kt5393.kt");