JVM IR: Don't move inaccessible const fields out of interface companions

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/MoveCompanionObjectFieldsLowering.kt

@@ -27,7 +27,9 @@ import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.impl.IrAnonymousInitializerSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrFieldSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrVariableSymbolImpl
-import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.util.hasAnnotation
+import org.jetbrains.kotlin.ir.util.isObject
+import org.jetbrains.kotlin.ir.util.patchDeclarationParents
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.load.java.JvmAbi.JVM_FIELD_ANNOTATION_FQ_NAME
@@ -96,11 +98,13 @@ private class MoveOrCopyCompanionObjectFieldsLowering(val context: CommonBackend
         val companion = irClass.declarations.find {
             it is IrClass && it.isCompanion
         } as IrClass? ?: return
-        companion.declarations.filter { it is IrProperty && it.isConst }.mapNotNullTo(irClass.declarations) {
+        companion.declarations.filter { it is IrProperty && it.isConst && it.hasPublicVisibility }
-            copyPropertyFieldToStaticParent(it as IrProperty, companion, irClass)
+            .mapNotNullTo(irClass.declarations) { copyPropertyFieldToStaticParent(it as IrProperty, companion, irClass) }
-        }
     }
 
+    private val IrProperty.hasPublicVisibility: Boolean
+        get() = !Visibilities.isPrivate(visibility) && visibility != Visibilities.PROTECTED
+
     private fun IrClass.allFieldsAreJvmField() =
         declarations.filterIsInstance<IrProperty>()
             .mapNotNull { it.backingField }.all { it.hasAnnotation(JVM_FIELD_ANNOTATION_FQ_NAME) }

compiler/testData/writeFlags/property/classObject/trait/privateConstVal.kt

@@ -0,0 +1,13 @@
+interface Test {
+    companion object {
+        private const val prop: Int = 0
+    }
+}
+
+// TESTED_OBJECT_KIND: property
+// TESTED_OBJECTS: Test, prop
+// ABSENT: TRUE
+
+// TESTED_OBJECT_KIND: property
+// TESTED_OBJECTS: Test$Companion, prop
+// FLAGS: ACC_PRIVATE, ACC_FINAL, ACC_STATIC

compiler/testData/writeFlags/property/classObject/trait/protectedConstVal.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 interface Test {
   companion object {
     protected const val prop: Int = 0

compiler/tests/org/jetbrains/kotlin/codegen/flags/WriteFlagsTestGenerated.java

@@ -1039,6 +1039,11 @@ public class WriteFlagsTestGenerated extends AbstractWriteFlagsTest {
                     runTest("compiler/testData/writeFlags/property/classObject/trait/noBackingField.kt");
                 }
 
+                @TestMetadata("privateConstVal.kt")
+                public void testPrivateConstVal() throws Exception {
+                    runTest("compiler/testData/writeFlags/property/classObject/trait/privateConstVal.kt");
+                }
+
                 @TestMetadata("privateVal.kt")
                 public void testPrivateVal() throws Exception {
                     runTest("compiler/testData/writeFlags/property/classObject/trait/privateVal.kt");

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

@@ -1039,6 +1039,11 @@ public class IrWriteFlagsTestGenerated extends AbstractIrWriteFlagsTest {
                     runTest("compiler/testData/writeFlags/property/classObject/trait/noBackingField.kt");
                 }
 
+                @TestMetadata("privateConstVal.kt")
+                public void testPrivateConstVal() throws Exception {
+                    runTest("compiler/testData/writeFlags/property/classObject/trait/privateConstVal.kt");
+                }
+
                 @TestMetadata("privateVal.kt")
                 public void testPrivateVal() throws Exception {
                     runTest("compiler/testData/writeFlags/property/classObject/trait/privateVal.kt");