JVM: Don't generate accessors to companions in earlier language versions

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

@@ -2862,7 +2862,7 @@ public class ExpressionCodegen extends KtVisitor<StackValue, StackValue> impleme
         }
     }
 
-    private static CodegenContext getContextForCompanionObjectAccessorIfRequiredOrNull(
+    private CodegenContext getContextForCompanionObjectAccessorIfRequiredOrNull(
             @NotNull ClassDescriptor companionObjectDescriptor,
             @NotNull CodegenContext contextBeforeInline
     ) {
@@ -2870,6 +2870,10 @@ public class ExpressionCodegen extends KtVisitor<StackValue, StackValue> impleme
             return null;
         }
 
+        if (!state.getLanguageVersionSettings().supportsFeature(LanguageFeature.ProperVisibilityForCompanionObjectInstanceField)) {
+            return null;
+        }
+
         int accessFlag = AsmUtil.getVisibilityAccessFlag(companionObjectDescriptor);
 
         CodegenContext context = contextBeforeInline.getFirstCrossInlineOrNonInlineContext();

compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_after.kt

@@ -0,0 +1,13 @@
+// !LANGUAGE: +ProperVisibilityForCompanionObjectInstanceField
+// IGNORE_BACKEND: JVM_IR
+// ^ TODO implement ProperVisibilityForCompanionObjectInstanceField feature support in JMV_IR
+
+class Host {
+    private companion object {
+        fun foo() = 1
+    }
+
+    fun test() = { foo() }
+}
+
+// 1 synthetic access\$

compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_before.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: -ProperVisibilityForCompanionObjectInstanceField
+
+class Host {
+    private companion object {
+        fun foo() = 1
+    }
+
+    fun test() = { foo() }
+}
+
+// 0 synthetic access\$

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

@@ -920,6 +920,16 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
         public void testKt14258_5() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/companion/kt14258_5.kt");
         }
+
+        @TestMetadata("privateCompanionObjectAccessors_after.kt")
+        public void testPrivateCompanionObjectAccessors_after() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_after.kt");
+        }
+
+        @TestMetadata("privateCompanionObjectAccessors_before.kt")
+        public void testPrivateCompanionObjectAccessors_before() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_before.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/bytecodeText/conditions")

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

@@ -920,6 +920,16 @@ public class IrBytecodeTextTestGenerated extends AbstractIrBytecodeTextTest {
         public void testKt14258_5() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/companion/kt14258_5.kt");
         }
+
+        @TestMetadata("privateCompanionObjectAccessors_after.kt")
+        public void testPrivateCompanionObjectAccessors_after() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_after.kt");
+        }
+
+        @TestMetadata("privateCompanionObjectAccessors_before.kt")
+        public void testPrivateCompanionObjectAccessors_before() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_before.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/bytecodeText/conditions")