Fix issues with enum entry self-reference

Given a singleton class 'S' with possibly uninitialized static instance
(enum entry, interface companion object).
Such singleton can be referenced by name, or as an explicit or implicit
'this'.
For a given singleton class 'S' we
either use 'this@S' from context (local or captured),
or 'S' as a static instance.

Local or captured 'this@S' should be used if:
  - we are in the constructor for 'S',
    and corresponding instance is initialized
        by super or delegating constructor call;
  - we are in any other member of 'S' or any of its inner classes.

Otherwise, a static instance should be used.

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

@@ -1723,12 +1723,22 @@ public class ExpressionCodegen extends KtVisitor<StackValue, StackValue> impleme
     }
 
     private boolean shouldGenerateSingletonAsThisOrOuterFromContext(ClassDescriptor classDescriptor) {
-        return isPossiblyUninitializedSingleton(classDescriptor) &&
-               isInsideSingleton(classDescriptor) &&
-               isThisInitialized(classDescriptor);
-    }
+        if (!isPossiblyUninitializedSingleton(classDescriptor)) return false;
+        if (!isInsideSingleton(classDescriptor)) return false;
+
+        // We are inside a singleton class 'S' with possibly uninitialized static instance
+        // (enum entry, interface companion object).
+        // Such singleton can be referenced by name, or as an explicit or implicit 'this'.
+        // For a given singleton class 'S' we either use 'this@S' from context (local or captured),
+        // or 'S' as a static instance.
+        //
+        // Local or captured 'this@S' should be used if:
+        // - we are in the constructor for 'S',
+        //   and corresponding instance is initialized by super or delegating constructor call;
+        // - we are in any other member of 'S' or any of its inner classes.
+        //
+        // Otherwise, a static instance should be used.
 
-    private boolean isThisInitialized(ClassDescriptor classDescriptor) {
         CodegenContext context = this.context;
         while (context != null) {
             if (context instanceof ConstructorContext) {
@@ -1738,9 +1748,24 @@ public class ExpressionCodegen extends KtVisitor<StackValue, StackValue> impleme
                     return constructorContext.isThisInitialized();
                 }
             }
+            else if (context instanceof ClassContext) {
+                ClassDescriptor contextClass = ((ClassContext) context).getContextDescriptor();
+                if (isInInnerClassesChainFor(contextClass, classDescriptor)) {
+                    return true;
+                }
+            }
             context = context.getParentContext();
         }
-        return true;
+        return false;
+    }
+
+    private static boolean isInInnerClassesChainFor(ClassDescriptor innerClass, ClassDescriptor outerClass) {
+        if (innerClass == outerClass) return true;
+        if (!innerClass.isInner()) return false;
+
+        DeclarationDescriptor containingDeclaration = innerClass.getContainingDeclaration();
+        if (!(containingDeclaration instanceof ClassDescriptor)) return false;
+        return isInInnerClassesChainFor((ClassDescriptor) containingDeclaration, outerClass);
     }
 
     @Nullable

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor1.kt

@@ -0,0 +1,24 @@
+interface IFoo {
+    fun foo(): String
+}
+
+interface IBar {
+    fun bar(): String
+}
+
+abstract class Base(val x: IFoo)
+
+enum class Test : IFoo, IBar {
+    FOO {
+        // FOO referenced from inner class constructor with uninitialized 'this'
+        inner class Inner : Base(FOO)
+
+        val z = Inner()
+
+        override fun foo() = "OK"
+
+        override fun bar() = z.x.foo()
+    }
+}
+
+fun box() = Test.FOO.bar()

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor2.kt

@@ -0,0 +1,24 @@
+interface IFoo {
+    fun foo(): String
+}
+
+interface IBar {
+    fun bar(): String
+}
+
+enum class Test : IFoo, IBar {
+    FOO {
+        // FOO referenced from inner class constructor with initialized 'this'
+        inner class Inner {
+            val fooFoo = FOO.foo()
+        }
+
+        val z = Inner()
+
+        override fun foo() = "OK"
+
+        override fun bar() = z.fooFoo
+    }
+}
+
+fun box() = Test.FOO.bar()

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt

@@ -0,0 +1,23 @@
+interface IFoo {
+    fun foo(): String
+}
+
+interface IBar {
+    fun bar(): String
+}
+
+enum class Test : IFoo, IBar {
+    FOO {
+        // FOO referenced from inner class constructor with initialized 'this',
+        // in delegate initializer
+        inner class Inner : IFoo by FOO
+
+        val z = Inner()
+
+        override fun foo() = "OK"
+
+        override fun bar() = z.foo()
+    }
+}
+
+fun box() = Test.FOO.bar()

compiler/testData/codegen/box/enum/kt20651a.kt

@@ -0,0 +1,8 @@
+enum class Foo(
+        val x: String,
+        val callback: () -> String
+) {
+    FOO("OK", { FOO.x })
+}
+
+fun box() = Foo.FOO.callback()

compiler/testData/codegen/box/enum/kt20651b.kt

@@ -0,0 +1,17 @@
+interface Callback {
+    fun invoke(): String
+}
+
+enum class Foo(
+        val x: String,
+        val callback: Callback
+) {
+    FOO(
+            "OK",
+            object : Callback {
+                override fun invoke() = FOO.x
+            }
+    )
+}
+
+fun box() = Foo.FOO.callback.invoke()

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

@@ -7934,6 +7934,24 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor1.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor1.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor2.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor2.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor3.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("enumInheritedFromTrait.kt")
         public void testEnumInheritedFromTrait() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumInheritedFromTrait.kt");
@@ -8012,6 +8030,18 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("kt20651a.kt")
+        public void testKt20651a() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651a.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("kt20651b.kt")
+        public void testKt20651b() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651b.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt2350.kt")
         public void testKt2350() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt2350.kt");

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

@@ -7934,6 +7934,24 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor1.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor1.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor2.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor2.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor3.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("enumInheritedFromTrait.kt")
         public void testEnumInheritedFromTrait() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumInheritedFromTrait.kt");
@@ -8012,6 +8030,18 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("kt20651a.kt")
+        public void testKt20651a() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651a.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("kt20651b.kt")
+        public void testKt20651b() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651b.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt2350.kt")
         public void testKt2350() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt2350.kt");

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

@@ -7934,6 +7934,24 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             doTest(fileName);
         }
 
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor1.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor1.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor2.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor2.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor3.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("enumInheritedFromTrait.kt")
         public void testEnumInheritedFromTrait() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumInheritedFromTrait.kt");
@@ -8012,6 +8030,18 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             doTest(fileName);
         }
 
+        @TestMetadata("kt20651a.kt")
+        public void testKt20651a() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651a.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("kt20651b.kt")
+        public void testKt20651b() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651b.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt2350.kt")
         public void testKt2350() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt2350.kt");

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

@@ -8600,6 +8600,24 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             doTest(fileName);
         }
 
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor1.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor1.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor2.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor2.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("enumEntryReferenceFromInnerClassConstructor3.kt")
+        public void testEnumEntryReferenceFromInnerClassConstructor3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("enumInheritedFromTrait.kt")
         public void testEnumInheritedFromTrait() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumInheritedFromTrait.kt");
@@ -8678,6 +8696,18 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             doTest(fileName);
         }
 
+        @TestMetadata("kt20651a.kt")
+        public void testKt20651a() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651a.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("kt20651b.kt")
+        public void testKt20651b() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt20651b.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt2350.kt")
         public void testKt2350() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/kt2350.kt");