FIR2IR: convert enums with non-primary default ctor correctly

see added test for example

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt

@@ -27,13 +27,11 @@ import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrExternalPackageFragmentImpl
-import org.jetbrains.kotlin.ir.expressions.impl.IrEnumConstructorCallImpl
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.symbols.impl.*
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
 import org.jetbrains.kotlin.ir.util.IdSignature
-import org.jetbrains.kotlin.ir.util.constructors
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.StandardClassIds
@@ -528,7 +526,6 @@ class Fir2IrClassifierStorage(
                     startOffset, endOffset, origin, symbol, enumEntry.name
                 ).apply {
                     declarationStorage.enterScope(this)
-                    val irType = enumEntry.returnTypeRef.toIrType()
                     if (irParent != null) {
                         this.parent = irParent
                     }
@@ -541,15 +538,6 @@ class Fir2IrClassifierStorage(
                         }
                         // Otherwise, this is a default-ish enum entry whose initializer would be a delegating constructor call,
                         // which will be translated via visitor later.
-                    } else if (irParent != null && origin == IrDeclarationOrigin.DEFINED) {
-                        val constructor = irParent.constructors.first()
-                        this.initializerExpression = factory.createExpressionBody(
-                            IrEnumConstructorCallImpl(
-                                startOffset, endOffset, irType, constructor.symbol,
-                                valueArgumentsCount = constructor.valueParameters.size,
-                                typeArgumentsCount = constructor.typeParameters.size
-                            )
-                        )
                     }
                     declarationStorage.leaveScope(this)
                 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -234,6 +234,7 @@ class Fir2IrConverter(
         if (irConstructor != null) {
             irClass.declarations += irConstructor
         }
+        // At least on enum entry creation we may need a default constructor, so ctors should be converted first
         for (declaration in syntheticPropertiesLast(allDeclarations)) {
             val irDeclaration = processMemberDeclaration(declaration, regularClass, irClass) ?: continue
             irClass.declarations += irDeclaration
@@ -294,7 +295,7 @@ class Fir2IrConverter(
     // Sort declarations so that all non-synthetic declarations are before synthetic ones.
     // This is needed because converting synthetic fields for implementation delegation needs to know
     // existing declarations in the class to avoid adding redundant delegated members.
-    private fun syntheticPropertiesLast(declarations: List<FirDeclaration>): Iterable<FirDeclaration> {
+    private fun syntheticPropertiesLast(declarations: Iterable<FirDeclaration>): Iterable<FirDeclaration> {
         return declarations.sortedBy { it !is FirField && it.isSynthetic }
     }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -47,6 +47,7 @@ import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.types.impl.IrErrorTypeImpl
 import org.jetbrains.kotlin.ir.util.constructors
+import org.jetbrains.kotlin.ir.util.defaultConstructor
 import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.parentClassOrNull
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -116,6 +117,8 @@ class Fir2IrVisitor(
         annotationGenerator.generate(irEnumEntry, enumEntry)
         val correspondingClass = irEnumEntry.correspondingClass
         val initializer = enumEntry.initializer
+        val irType = enumEntry.returnTypeRef.toIrType()
+        val irParentEnumClass = irEnumEntry.parent as? IrClass
         // If the enum entry has its own members, we need to introduce a synthetic class.
         if (correspondingClass != null) {
             declarationStorage.enterScope(irEnumEntry)
@@ -129,7 +132,7 @@ class Fir2IrVisitor(
                 val constructor = correspondingClass.constructors.first()
                 irEnumEntry.initializerExpression = irFactory.createExpressionBody(
                     IrEnumConstructorCallImpl(
-                        startOffset, endOffset, enumEntry.returnTypeRef.toIrType(),
+                        startOffset, endOffset, irType,
                         constructor.symbol,
                         typeArgumentsCount = constructor.typeParameters.size,
                         valueArgumentsCount = constructor.valueParameters.size
@@ -148,6 +151,20 @@ class Fir2IrVisitor(
                     )
                 }
             }
+        } else if (irParentEnumClass != null && initializer == null) {
+            // a default-ish enum entry whose initializer would be a delegating constructor call
+            val constructor =
+                irParentEnumClass.defaultConstructor ?: error("Assuming that default constructor should exist and be converted at this point")
+            enumEntry.convertWithOffsets { startOffset, endOffset ->
+                irEnumEntry.initializerExpression = irFactory.createExpressionBody(
+                    IrEnumConstructorCallImpl(
+                        startOffset, endOffset, irType, constructor.symbol,
+                        valueArgumentsCount = constructor.valueParameters.size,
+                        typeArgumentsCount = constructor.typeParameters.size
+                    )
+                )
+                irEnumEntry
+            }
         }
         return irEnumEntry
     }

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -16956,6 +16956,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @Test
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @Test
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -213,6 +213,9 @@ val IrClassSymbol.functions: Sequence<IrSimpleFunctionSymbol>
 val IrClass.constructors: Sequence<IrConstructor>
     get() = declarations.asSequence().filterIsInstance<IrConstructor>()
 
+val IrClass.defaultConstructor: IrConstructor?
+    get() = constructors.firstOrNull { ctor -> ctor.valueParameters.all { it.defaultValue != null } }
+
 val IrClassSymbol.constructors: Sequence<IrConstructorSymbol>
     get() = owner.constructors.map { it.symbol }
 

compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt

@@ -0,0 +1,16 @@
+
+enum class Test {
+    A(0),
+    B;
+
+    val n: Int
+
+    constructor(n: Int) { this.n = n }
+    constructor() : this(0)
+}
+
+fun box(): String =
+    if (Test.A.n == Test.B.n)
+        "OK"
+    else
+        "Fail"

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java

@@ -16674,6 +16674,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @Test
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @Test
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -16956,6 +16956,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @Test
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @Test
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {

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

@@ -13761,6 +13761,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/secondaryConstructorWithDefaultArguments.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java

@@ -12860,6 +12860,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @Test
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @Test
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java

@@ -12956,6 +12956,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @Test
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @Test
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/testOld/wasm/semantics/IrCodegenBoxWasmTestGenerated.java

@@ -11486,6 +11486,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
             }
 
+            @TestMetadata("noPrimaryConstructor.kt")
+            public void testNoPrimaryConstructor() throws Exception {
+                runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+            }
+
             @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
             public void testSecondaryConstructorWithDefaultArguments() throws Exception {
                 runTest("compiler/testData/codegen/box/enum/defaultCtor/secondaryConstructorWithDefaultArguments.kt");

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java

@@ -13968,6 +13968,12 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                     runTest("compiler/testData/codegen/box/enum/defaultCtor/entryClassConstructorWithVarargs.kt");
                 }
 
+                @Test
+                @TestMetadata("noPrimaryConstructor.kt")
+                public void testNoPrimaryConstructor() throws Exception {
+                    runTest("compiler/testData/codegen/box/enum/defaultCtor/noPrimaryConstructor.kt");
+                }
+
                 @Test
                 @TestMetadata("secondaryConstructorWithDefaultArguments.kt")
                 public void testSecondaryConstructorWithDefaultArguments() throws Exception {