[Wasm] Allow implementing function interfaces

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSCompilerArguments.kt

@@ -391,6 +391,9 @@ class K2JSCompilerArguments : CommonCompilerArguments() {
             if (isIrBackendEnabled()) {
                 this[LanguageFeature.JsAllowValueClassesInExternals] = LanguageFeature.State.ENABLED
             }
+            if (wasm) {
+                this[LanguageFeature.JsAllowImplementingFunctionInterface] = LanguageFeature.State.ENABLED
+            }
         }
     }
 }

compiler/testData/codegen/box/classes/kt1535.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IMPLEMENTING_FUNCTION_INTERFACE
 // IGNORE_BACKEND: JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 // TODO: Enable when JS backend supports Java class library, since FunctionX are required for interoperation

compiler/testData/codegen/box/closures/closureOnTopLevel1.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IMPLEMENTING_FUNCTION_INTERFACE
 // IGNORE_BACKEND: JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 // TODO: muted automatically, investigate should it be ran for JS or not

compiler/testData/codegen/box/closures/closureOnTopLevel2.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IMPLEMENTING_FUNCTION_INTERFACE
 // IGNORE_BACKEND: JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 // TODO: muted automatically, investigate should it be ran for JS or not

compiler/testData/codegen/box/coroutines/suspendConversion/intersectionTypeToSubtypeConversion.kt

@@ -4,8 +4,6 @@
 // IGNORE_BACKEND: JVM, JS, JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 // IGNORE_LIGHT_ANALYSIS
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IGNORED_IN_JS
 
 import helpers.*
 import kotlin.coroutines.*

compiler/testData/codegen/box/coroutines/suspendConversion/subtypeOfFunctionalTypeToSuspendConversion.kt

@@ -4,8 +4,6 @@
 // IGNORE_BACKEND: JVM, JS, JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 // IGNORE_LIGHT_ANALYSIS
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IGNORED_IN_JS
 
 import helpers.*
 import kotlin.coroutines.*

compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt

@@ -1,5 +1,5 @@
 // !LANGUAGE: +FunctionalTypeWithExtensionAsSupertype
-// IGNORE_BACKEND: JS, JS_IR, WASM
+// IGNORE_BACKEND: JS, JS_IR
 
 interface I: (String) -> String
 

compiler/testData/codegen/box/funInterface/intersectionTypeToFunInterfaceConversion.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IGNORED_IN_JS
 // IGNORE_BACKEND: JS, JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 

compiler/testData/codegen/box/funInterface/subtypeOfFunctionalTypeToFunInterfaceConversion.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IGNORED_IN_JS
 // IGNORE_BACKEND: JS, JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 

compiler/testData/codegen/box/functions/bigArity/subclass.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IGNORED_IN_JS
 // !LANGUAGE: +FunctionTypesWithBigArity
 
 // Implementing function interface is prohibited in JavaScript

compiler/testData/codegen/box/functions/invoke/kt3190.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IGNORED_IN_JS
 // IGNORE_BACKEND: JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 //KT-3190 Compiler crash if function called 'invoke' calls a closure

compiler/testData/codegen/box/functions/invoke/kt3822invokeOnThis.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: IMPLEMENTING_FUNCTION_INTERFACE
 // IGNORE_BACKEND_K1: JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 //KT-3822 Compiler crashes when use invoke convention with `this` in class which extends Function0<T>

compiler/tests-common/tests/org/jetbrains/kotlin/checkers/CompilerTestLanguageVersionSettings.kt

@@ -53,7 +53,11 @@ private fun specificFeaturesForTests(): Map<LanguageFeature, LanguageFeature.Sta
 fun parseLanguageVersionSettingsOrDefault(directiveMap: Directives): CompilerTestLanguageVersionSettings =
     parseLanguageVersionSettings(directiveMap) ?: defaultLanguageVersionSettings()
 
-fun parseLanguageVersionSettings(directives: Directives): CompilerTestLanguageVersionSettings? {
+@JvmOverloads
+fun parseLanguageVersionSettings(
+    directives: Directives,
+    extraLanguageFeatures: Map<LanguageFeature, LanguageFeature.State> = emptyMap()
+): CompilerTestLanguageVersionSettings? {
     val apiVersionString = directives[API_VERSION_DIRECTIVE]
     val languageFeaturesString = directives[LANGUAGE_DIRECTIVE]
 
@@ -81,7 +85,7 @@ fun parseLanguageVersionSettings(directives: Directives): CompilerTestLanguageVe
 
     val languageVersion = maxOf(LanguageVersion.LATEST_STABLE, LanguageVersion.fromVersionString(apiVersion.versionString)!!)
 
-    val languageFeatures = languageFeaturesString?.let(::collectLanguageFeatureMap).orEmpty()
+    val languageFeatures = languageFeaturesString?.let(::collectLanguageFeatureMap).orEmpty() + extraLanguageFeatures
 
     return CompilerTestLanguageVersionSettings(languageFeatures, apiVersion, languageVersion, mapOf(*analysisFlags.toTypedArray()))
 }

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

@@ -315,6 +315,7 @@ enum class LanguageFeature(
     ValueClasses(sinceVersion = null, kind = UNSTABLE_FEATURE),
     JavaSamConversionEqualsHashCode(sinceVersion = null, kind = UNSTABLE_FEATURE),
     UnitConversionsOnArbitraryExpressions(sinceVersion = null),
+    JsAllowImplementingFunctionInterface(sinceVersion = null, kind = UNSTABLE_FEATURE),
     ;
 
     init {

js/js.frontend/src/org/jetbrains/kotlin/js/resolve/diagnostics/JsInheritanceChecker.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.js.resolve.diagnostics
 
 import org.jetbrains.kotlin.builtins.isBuiltinFunctionalTypeOrSubtype
 import org.jetbrains.kotlin.builtins.isSuspendFunctionTypeOrSubtype
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
@@ -44,10 +45,12 @@ object JsInheritanceChecker : DeclarationChecker {
             }
         }
 
-        if (descriptor is ClassDescriptor &&
+        if (!context.languageVersionSettings.supportsFeature(LanguageFeature.JsAllowImplementingFunctionInterface)) {
-            descriptor.defaultType.immediateSupertypes().any { it.isBuiltinFunctionalTypeOrSubtype && !it.isSuspendFunctionTypeOrSubtype }
+            if (descriptor is ClassDescriptor &&
-        ) {
+                descriptor.defaultType.immediateSupertypes().any { it.isBuiltinFunctionalTypeOrSubtype && !it.isSuspendFunctionTypeOrSubtype }
-            context.trace.report(ErrorsJs.IMPLEMENTING_FUNCTION_INTERFACE.on(declaration as KtClassOrObject))
+            ) {
+                context.trace.report(ErrorsJs.IMPLEMENTING_FUNCTION_INTERFACE.on(declaration as KtClassOrObject))
+            }
         }
     }
 

js/js.tests/test/org/jetbrains/kotlin/js/testOld/BasicWasmBoxTest.kt

@@ -45,6 +45,10 @@ abstract class BasicWasmBoxTest(
 
     private val COMMON_FILES_NAME = "_common"
 
+    private val extraLanguageFeatures = mapOf(
+        LanguageFeature.JsAllowImplementingFunctionInterface to LanguageFeature.State.ENABLED,
+    )
+
     fun doTest(filePath: String) = doTestWithTransformer(filePath) { it }
     fun doTestWithTransformer(filePath: String, transformer: java.util.function.Function<String, String>) {
         val file = File(filePath)
@@ -241,7 +245,7 @@ abstract class BasicWasmBoxTest(
         configuration.put(JSConfigurationKeys.WASM_ENABLE_ARRAY_RANGE_CHECKS, true)
         configuration.put(JSConfigurationKeys.WASM_ENABLE_ASSERTS, true)
         configuration.languageVersionSettings = languageVersionSettings
-            ?: LanguageVersionSettingsImpl(LanguageVersion.LATEST_STABLE, ApiVersion.LATEST_STABLE)
+            ?: LanguageVersionSettingsImpl(LanguageVersion.LATEST_STABLE, ApiVersion.LATEST_STABLE, specificFeatures = extraLanguageFeatures)
         return JsConfig(project, configuration, CompilerEnvironment, null, null)
     }
 
@@ -256,7 +260,7 @@ abstract class BasicWasmBoxTest(
                 }
             }
 
-            val languageVersionSettings = parseLanguageVersionSettings(directives)
+            val languageVersionSettings = parseLanguageVersionSettings(directives, extraLanguageFeatures)
 
             val temporaryFile = File(tmpDir, "WASM_TEST/$fileName")
             KtTestUtil.mkdirs(temporaryFile.parentFile)