JVM SamWrapperClassesAreSynthetic language feature

KT-44278 KT-26060 KT-42621

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

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.codegen.context.CodegenContext;
 import org.jetbrains.kotlin.codegen.context.FieldOwnerContext;
 import org.jetbrains.kotlin.codegen.state.GenerationState;
 import org.jetbrains.kotlin.codegen.state.KotlinTypeMapper;
+import org.jetbrains.kotlin.config.LanguageFeature;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.impl.ClassDescriptorImpl;
 import org.jetbrains.kotlin.fileClasses.JvmFileClassUtil;
@@ -79,7 +80,8 @@ public class SamWrapperCodegen {
         this.samType = samType;
         this.parentCodegen = parentCodegen;
         visibility = isInsideInline ? ACC_PUBLIC : NO_FLAG_PACKAGE_PRIVATE;
-        classFlags = visibility | ACC_FINAL | ACC_SUPER;
+        int synth = state.getLanguageVersionSettings().supportsFeature(LanguageFeature.SamWrapperClassesAreSynthetic) ? ACC_SYNTHETIC : 0;
+        classFlags = visibility | ACC_FINAL | ACC_SUPER | synth;
     }
 
     @NotNull

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -211,10 +211,10 @@ class GenerationState private constructor(
         val fromConfig = configuration.get(JVMConfigurationKeys.SAM_CONVERSIONS)
         if (fromConfig != null && target >= fromConfig.minJvmTarget)
             fromConfig
-        else if (target < JvmTarget.JVM_1_8)
-            JvmClosureGenerationScheme.CLASS
-        else
+        else if (target >= JvmTarget.JVM_1_8 && languageVersionSettings.supportsFeature(LanguageFeature.SamWrapperClassesAreSynthetic))
             JvmClosureGenerationScheme.INDY
+        else
+            JvmClosureGenerationScheme.CLASS
     }
 
     val lambdasScheme = run {

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ClassCodegen.kt

@@ -81,7 +81,7 @@ class ClassCodegen private constructor(
         defineClass(
             irClass.psiElement,
             state.classFileVersion,
-            irClass.flags,
+            irClass.getFlags(context.state.languageVersionSettings),
             signature.name,
             signature.javaGenericSignature,
             signature.superclassName,
@@ -473,10 +473,11 @@ class ClassCodegen private constructor(
         }
 }
 
-private val IrClass.flags: Int
-    get() = origin.flags or getVisibilityAccessFlagForClass() or
+private fun IrClass.getFlags(languageVersionSettings: LanguageVersionSettings): Int =
+    origin.flags or
+            getVisibilityAccessFlagForClass() or
             (if (isAnnotatedWithDeprecated) Opcodes.ACC_DEPRECATED else 0) or
-            (if (hasAnnotation(JVM_SYNTHETIC_ANNOTATION_FQ_NAME)) Opcodes.ACC_SYNTHETIC else 0) or
+            getSynthAccessFlag(languageVersionSettings) or
             when {
                 isAnnotationClass -> Opcodes.ACC_ANNOTATION or Opcodes.ACC_INTERFACE or Opcodes.ACC_ABSTRACT
                 isInterface -> Opcodes.ACC_INTERFACE or Opcodes.ACC_ABSTRACT
@@ -485,6 +486,16 @@ private val IrClass.flags: Int
                 else -> Opcodes.ACC_SUPER or modality.flags
             }
 
+private fun IrClass.getSynthAccessFlag(languageVersionSettings: LanguageVersionSettings): Int {
+    if (hasAnnotation(JVM_SYNTHETIC_ANNOTATION_FQ_NAME))
+        return Opcodes.ACC_SYNTHETIC
+    if (origin == IrDeclarationOrigin.GENERATED_SAM_IMPLEMENTATION &&
+        languageVersionSettings.supportsFeature(LanguageFeature.SamWrapperClassesAreSynthetic)
+    )
+        return Opcodes.ACC_SYNTHETIC
+    return 0
+}
+
 private fun IrField.computeFieldFlags(context: JvmBackendContext, languageVersionSettings: LanguageVersionSettings): Int =
     origin.flags or visibility.flags or
             (if (isDeprecatedCallable(context) ||

compiler/testData/codegen/bytecodeListing/sam/callableRefGenericFunInterface.txt

@@ -16,7 +16,7 @@ synthetic final class<Lkotlin/jvm/internal/FunctionReferenceImpl;Lkotlin/jvm/fun
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public <null> method equals(p0: java.lang.Object): boolean

compiler/testData/codegen/bytecodeListing/sam/callableRefGenericSamInterface.txt

@@ -10,7 +10,7 @@ synthetic final class<Lkotlin/jvm/internal/FunctionReferenceImpl;Lkotlin/jvm/fun
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method get(): java.lang.Object

compiler/testData/codegen/bytecodeListing/sam/callableRefSpecializedFunInterface.txt

@@ -5,7 +5,7 @@ public interface<<T:Ljava/lang/Object;>Ljava/lang/Object;>  Sam {
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public <null> method equals(p0: java.lang.Object): boolean

compiler/testData/codegen/bytecodeListing/sam/callableRefSpecializedSamInterface.txt

@@ -1,5 +1,5 @@
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method get(): java.lang.Object

compiler/testData/codegen/bytecodeListing/sam/genericFunInterface.txt

@@ -5,7 +5,7 @@ public interface<<T:Ljava/lang/Object;>Ljava/lang/Object;>  Sam {
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public <null> method equals(p0: java.lang.Object): boolean

compiler/testData/codegen/bytecodeListing/sam/genericFunInterface_ir.txt

@@ -5,7 +5,7 @@ public interface<<T:Ljava/lang/Object;>Ljava/lang/Object;>  Sam {
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     public final @org.jetbrains.annotations.NotNull <()Lkotlin/Function<*>;> method getFunctionDelegate(): kotlin.Function
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void

compiler/testData/codegen/bytecodeListing/sam/genericSamInterface.txt

@@ -1,5 +1,5 @@
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method get(): java.lang.Object

compiler/testData/codegen/bytecodeListing/sam/reusedSamWrapperClasses.txt

@@ -1,5 +1,5 @@
 @kotlin.Metadata
-final class A$sam$java_lang_Runnable$0 {
+synthetic final class A$sam$java_lang_Runnable$0 {
     // source: 'reusedSamWrapperClasses.kt'
     enclosing class A
     private synthetic final field function: kotlin.jvm.functions.Function0

compiler/testData/codegen/bytecodeListing/sam/samAdapterAndInlinedOne.txt

@@ -1,5 +1,5 @@
 @kotlin.Metadata
-public final class<null>  test/SamAdapterAndInlinedOneKt$sam$i$java_lang_Runnable$0 {
+public synthetic final class<null>  test/SamAdapterAndInlinedOneKt$sam$i$java_lang_Runnable$0 {
     // source: 'samAdapterAndInlinedOne.kt'
     public <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method run(): void
@@ -9,7 +9,7 @@ public final class<null>  test/SamAdapterAndInlinedOneKt$sam$i$java_lang_Runnabl
 }
 
 @kotlin.Metadata
-final class<null>  test/SamAdapterAndInlinedOneKt$sam$java_lang_Runnable$0 {
+synthetic final class<null>  test/SamAdapterAndInlinedOneKt$sam$java_lang_Runnable$0 {
     // source: 'samAdapterAndInlinedOne.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method run(): void

compiler/testData/codegen/bytecodeListing/sam/samAdapterAndInlinedOne_ir.txt

@@ -1,5 +1,5 @@
 @kotlin.Metadata
-public final class<null>  test/SamAdapterAndInlinedOneKt$sam$i$java_lang_Runnable$0 {
+public synthetic final class<null>  test/SamAdapterAndInlinedOneKt$sam$i$java_lang_Runnable$0 {
     // source: 'samAdapterAndInlinedOne.kt'
     public <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method run(): void
@@ -9,7 +9,7 @@ public final class<null>  test/SamAdapterAndInlinedOneKt$sam$i$java_lang_Runnabl
 }
 
 @kotlin.Metadata
-final class<null>  test/SamAdapterAndInlinedOneKt$sam$java_lang_Runnable$0 {
+synthetic final class<null>  test/SamAdapterAndInlinedOneKt$sam$java_lang_Runnable$0 {
     // source: 'samAdapterAndInlinedOne.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method run(): void

compiler/testData/codegen/bytecodeListing/sam/specializedFunInterface.txt

@@ -5,7 +5,7 @@ public interface<<T:Ljava/lang/Object;>Ljava/lang/Object;>  Sam {
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public <null> method equals(p0: java.lang.Object): boolean

compiler/testData/codegen/bytecodeListing/sam/specializedFunInterface_ir.txt

@@ -5,7 +5,7 @@ public interface<<T:Ljava/lang/Object;>Ljava/lang/Object;>  Sam {
 }
 
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     public final @org.jetbrains.annotations.NotNull <()Lkotlin/Function<*>;> method getFunctionDelegate(): kotlin.Function
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void

compiler/testData/codegen/bytecodeListing/sam/specializedSamInterface.txt

@@ -1,5 +1,5 @@
 @kotlin.Metadata
-final class<null>  TKt$sam$Sam$0 {
+synthetic final class<null>  TKt$sam$Sam$0 {
     // source: 't.kt'
     <null> method <init>(p0: kotlin.jvm.functions.Function0): void
     public synthetic final <null> method get(): java.lang.Object

compiler/testData/codegen/bytecodeListing/sam/wrapperInlinedFromAnotherClass.txt

@@ -59,7 +59,7 @@ public final class B$runnable2$1 {
 }
 
 @kotlin.Metadata
-public final class B$sam$i$java_lang_Runnable$0 {
+public synthetic final class B$sam$i$java_lang_Runnable$0 {
     // source: 'wrapperInlinedFromAnotherClass.kt'
     enclosing class B
     private synthetic final field function: kotlin.jvm.functions.Function0

compiler/testData/codegen/bytecodeListing/sam/wrapperInlinedFromAnotherClass_ir.txt

@@ -59,7 +59,7 @@ public final class B$runnable2$1 {
 }
 
 @kotlin.Metadata
-public final class B$sam$i$java_lang_Runnable$0 {
+public synthetic final class B$sam$i$java_lang_Runnable$0 {
     // source: 'wrapperInlinedFromAnotherClass.kt'
     enclosing class B
     private synthetic final field function: kotlin.jvm.functions.Function0

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -199,6 +199,7 @@ enum class LanguageFeature(
     InlineClasses(sinceVersion = KOTLIN_1_3, defaultState = State.ENABLED_WITH_WARNING, kind = UNSTABLE_FEATURE),
     JvmInlineValueClasses(sinceVersion = KOTLIN_1_5, defaultState = State.ENABLED, kind = OTHER),
     SuspendFunctionsInFunInterfaces(sinceVersion = KOTLIN_1_5, defaultState = State.ENABLED, kind = OTHER),
+    SamWrapperClassesAreSynthetic(sinceVersion = KOTLIN_1_5, defaultState = State.ENABLED, kind = BUG_FIX)
     ;
 
     val presentableName: String