JS: support SAM conversion

The SAM adapter is generate on declaration site. This is different
from the JVM approach.

`external fun interface` is banned for now.

Reusing interface declaration for the adapter is a hack which
reduces code size and makes importing/exporting the adapter
effortless.

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

@@ -1,6 +1,5 @@
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JS
 // SKIP_DCE_DRIVEN
 
 fun interface Foo {

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

@@ -0,0 +1,33 @@
+// !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+
+// IGNORE_BACKEND: JVM, JVM_IR, JS_IR
+// IGNORE_BACKEND_FIR: JVM_IR
+// SKIP_DCE_DRIVEN
+
+fun interface Base {
+    fun doStuff(): String
+}
+
+fun interface I : Base
+
+fun interface Proxy : I {
+
+    override fun doStuff(): String = doStuffInt().toString()
+
+    fun doStuffInt(): Int
+}
+
+fun runBase(b: Base) = b.doStuff()
+
+fun runI(i: I) = i.doStuff()
+
+fun runProxy(p: Proxy) = p.doStuff()
+
+fun box(): String {
+
+    if (runI { "i" } != "i") return "fail1"
+
+    if (runProxy { 10 } != "10") return "fail2"
+
+    return runBase { "OK" }
+}

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

@@ -0,0 +1,32 @@
+// !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+
+// IGNORE_BACKEND_FIR: JVM_IR
+// SKIP_DCE_DRIVEN
+
+// MODULE: m1
+// FILE: m1.kt
+
+fun interface I {
+    fun f(): String
+}
+
+fun rn(i: I) = i.f()
+
+inline fun rnInline(i: I) = i.f()
+
+// MODULE: m2(m1)
+// FILE: m2.kt
+
+fun rn2(f: () -> String) = rn(f)
+
+inline fun rn2Inline(noinline f: () -> String) = rnInline(f)
+
+// MODULE: main(m2)
+// FILE: main.kt
+
+fun box(): String {
+
+    if (rn2Inline { "inline" } != "inline") return "fail"
+
+    return rn2 { "OK" }
+}

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

@@ -1,6 +1,5 @@
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JS
 // WITH_RUNTIME
 // SKIP_DCE_DRIVEN
 

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

@@ -1,6 +1,5 @@
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JS
 // WITH_RUNTIME
 // SKIP_DCE_DRIVEN
 

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

@@ -0,0 +1,20 @@
+// !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+
+// IGNORE_BACKEND_FIR: JVM_IR
+// SKIP_DCE_DRIVEN
+
+// This test should check argument coercion between the SAM and the lambda.
+// For now it checks that Char is boxed in JS
+
+fun interface CharToAny {
+    fun invoke(c: Char): Any
+}
+
+fun foo(c: CharToAny): Any = c.invoke('O')
+
+fun box(): String {
+
+    if (foo { it } !is Char) return "fail"
+
+    return "OK"
+}

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

@@ -1,6 +1,5 @@
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JS
 // WITH_RUNTIME
 // SKIP_DCE_DRIVEN
 

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

@@ -1,11 +1,11 @@
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JS, JS_IR
+// IGNORE_BACKEND: JS_IR
 // WITH_COROUTINES
 // WITH_RUNTIME
 
 import helpers.*
-import kotlin.coroutines.startCoroutine
+import kotlin.coroutines.*
 
 fun interface SuspendRunnable {
     suspend fun invoke()
@@ -17,11 +17,25 @@ fun run(r: SuspendRunnable) {
 
 var result = "initial"
 
+var resumingCallback: () -> Unit = {}
+
 suspend fun bar() {
+    // Generate proper state machine
+    suspendCoroutine<Unit> { cont ->
+        resumingCallback = {
+            cont.resume(Unit)
+        }
+    }
+
     result = "OK"
 }
 
 fun box(): String {
     run(::bar)
+
+    if (result != "initial") return "fail"
+
+    resumingCallback()
+
     return result
 }

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

@@ -11723,11 +11723,21 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/funInterface/castFromAny.kt");
         }
 
+        @TestMetadata("funInterfaceInheritance.kt")
+        public void testFunInterfaceInheritance() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt");
+        }
+
         @TestMetadata("inlinedSamWrapper.kt")
         public void testInlinedSamWrapper() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/inlinedSamWrapper.kt");
         }
 
+        @TestMetadata("multimodule.kt")
+        public void testMultimodule() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/multimodule.kt");
+        }
+
         @TestMetadata("nullableSam.kt")
         public void testNullableSam() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/nullableSam.kt");
@@ -11738,6 +11748,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
         }
 
+        @TestMetadata("primitiveConversions.kt")
+        public void testPrimitiveConversions() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
+        }
+
         @TestMetadata("receiverEvaluatedOnce.kt")
         public void testReceiverEvaluatedOnce() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");

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

@@ -11700,6 +11700,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)
     public static class FunInterface extends AbstractLightAnalysisModeTest {
+        @TestMetadata("funInterfaceInheritance.kt")
+        public void ignoreFunInterfaceInheritance() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt");
+        }
+
         private void runTest(String testDataFilePath) throws Exception {
             KotlinTestUtils.runTest(this::doTest, TargetBackend.JVM, testDataFilePath);
         }
@@ -11728,6 +11733,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/funInterface/inlinedSamWrapper.kt");
         }
 
+        @TestMetadata("multimodule.kt")
+        public void testMultimodule() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/multimodule.kt");
+        }
+
         @TestMetadata("nullableSam.kt")
         public void testNullableSam() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/nullableSam.kt");
@@ -11738,6 +11748,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
         }
 
+        @TestMetadata("primitiveConversions.kt")
+        public void testPrimitiveConversions() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
+        }
+
         @TestMetadata("receiverEvaluatedOnce.kt")
         public void testReceiverEvaluatedOnce() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");

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

@@ -10593,11 +10593,21 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/funInterface/castFromAny.kt");
         }
 
+        @TestMetadata("funInterfaceInheritance.kt")
+        public void testFunInterfaceInheritance() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt");
+        }
+
         @TestMetadata("inlinedSamWrapper.kt")
         public void testInlinedSamWrapper() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/inlinedSamWrapper.kt");
         }
 
+        @TestMetadata("multimodule.kt")
+        public void testMultimodule() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/multimodule.kt");
+        }
+
         @TestMetadata("nullableSam.kt")
         public void testNullableSam() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/nullableSam.kt");
@@ -10608,6 +10618,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
         }
 
+        @TestMetadata("primitiveConversions.kt")
+        public void testPrimitiveConversions() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
+        }
+
         @TestMetadata("receiverEvaluatedOnce.kt")
         public void testReceiverEvaluatedOnce() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");

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

@@ -10593,11 +10593,21 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/funInterface/castFromAny.kt");
         }
 
+        @TestMetadata("funInterfaceInheritance.kt")
+        public void testFunInterfaceInheritance() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt");
+        }
+
         @TestMetadata("inlinedSamWrapper.kt")
         public void testInlinedSamWrapper() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/inlinedSamWrapper.kt");
         }
 
+        @TestMetadata("multimodule.kt")
+        public void testMultimodule() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/multimodule.kt");
+        }
+
         @TestMetadata("nullableSam.kt")
         public void testNullableSam() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/nullableSam.kt");
@@ -10608,6 +10618,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
         }
 
+        @TestMetadata("primitiveConversions.kt")
+        public void testPrimitiveConversions() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
+        }
+
         @TestMetadata("receiverEvaluatedOnce.kt")
         public void testReceiverEvaluatedOnce() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -9073,6 +9073,16 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/funInterface/basicFunInterfaceConversion.kt");
         }
 
+        @TestMetadata("funInterfaceInheritance.kt")
+        public void testFunInterfaceInheritance() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt");
+        }
+
+        @TestMetadata("multimodule.kt")
+        public void testMultimodule() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/multimodule.kt");
+        }
+
         @TestMetadata("nullableSam.kt")
         public void testNullableSam() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/nullableSam.kt");
@@ -9083,6 +9093,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
         }
 
+        @TestMetadata("primitiveConversions.kt")
+        public void testPrimitiveConversions() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
+        }
+
         @TestMetadata("receiverEvaluatedOnce.kt")
         public void testReceiverEvaluatedOnce() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");

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

@@ -9073,6 +9073,16 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/funInterface/basicFunInterfaceConversion.kt");
         }
 
+        @TestMetadata("funInterfaceInheritance.kt")
+        public void testFunInterfaceInheritance() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt");
+        }
+
+        @TestMetadata("multimodule.kt")
+        public void testMultimodule() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/multimodule.kt");
+        }
+
         @TestMetadata("nullableSam.kt")
         public void testNullableSam() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/nullableSam.kt");
@@ -9083,6 +9093,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
         }
 
+        @TestMetadata("primitiveConversions.kt")
+        public void testPrimitiveConversions() throws Exception {
+            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
+        }
+
         @TestMetadata("receiverEvaluatedOnce.kt")
         public void testReceiverEvaluatedOnce() throws Exception {
             runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");

js/js.translator/src/org/jetbrains/kotlin/js/translate/context/Namer.java

@@ -131,6 +131,8 @@ public final class Namer {
 
     public static final String IMPORTS_FOR_INLINE_PROPERTY = "$$importsForInline$$";
 
+    public static final String SAM_FIELD_NAME = "function$";
+
     @NotNull
     public static String getFunctionTag(@NotNull CallableDescriptor functionDescriptor, @NotNull JsConfig config) {
         String intrinsicTag = ArrayFIF.INSTANCE.getTag(functionDescriptor, config);

js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/ClassTranslator.kt

@@ -119,6 +119,8 @@ class ClassTranslator private constructor(
             enumInitFunction.body.statements += JsAstUtils.asSyntheticStatement(initInvocation.source(companionDescriptor.source.getPsi()))
         }
 
+        maybeConvertInterfaceToSamAdapter(context, constructorFunction)
+
         translatePrimaryConstructor(constructorFunction, context, delegationTranslator)
         addMetadataObject()
         addMetadataType()
@@ -562,6 +564,42 @@ class ClassTranslator private constructor(
         }
     }
 
+    private fun maybeConvertInterfaceToSamAdapter(context: TranslationContext, constructorFunction: JsFunction) {
+        if (!descriptor.isFun) return
+
+        val paramName = context.scope().declareFreshName("f")
+        constructorFunction.parameters += JsParameter(paramName)
+        constructorFunction.body.statements += JsBinaryOperation(
+            JsBinaryOperator.ASG,
+            pureFqn(Namer.SAM_FIELD_NAME, JsThisRef()),
+            JsNameRef(paramName)
+        ).makeStmt()
+
+        val samDescriptor = descriptor.unsubstitutedMemberScope
+            .getContributedDescriptors(DescriptorKindFilter.FUNCTIONS)
+            .filterIsInstance<FunctionDescriptor>()
+            .single { it.modality === Modality.ABSTRACT }
+
+        val function = context.getFunctionObject(samDescriptor)
+        val innerContext = context.newDeclaration(samDescriptor).translateAndAliasParameters(samDescriptor, function.parameters)
+
+        if (samDescriptor.isSuspend) {
+            function.fillCoroutineMetadata(innerContext, samDescriptor, hasController = false)
+        }
+
+        val parameters = listOfNotNull(samDescriptor.extensionReceiverParameter) +
+                samDescriptor.valueParameters +
+                listOfNotNull(innerContext.continuationParameterDescriptor)
+
+        val arguments = parameters.map {
+            TranslationUtils.coerce(innerContext, innerContext.getAliasForDescriptor(it)!!, context.currentModule.builtIns.anyType)
+        }
+
+        function.body = JsBlock(JsReturn(JsInvocation(pureFqn(Namer.SAM_FIELD_NAME, JsThisRef()), arguments)))
+
+        context.addDeclarationStatement(context.addFunctionToPrototype(descriptor, samDescriptor, function))
+    }
+
     private fun <T : JsNode> T.withDefaultLocation(): T = apply { source = classDeclaration }
 
     companion object {

js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/FunctionTranslator.kt

@@ -66,7 +66,9 @@ fun TranslationContext.translateAndAliasParameters(
     for (valueParameter in descriptor.valueParameters) {
         val name = getNameForDescriptor(valueParameter)
         val tmpName = JsScope.declareTemporaryName(name.ident).also { it.descriptor = valueParameter }
-        aliases[valueParameter] = JsAstUtils.pureFqn(tmpName, null)
+        val parameterRef = JsAstUtils.pureFqn(tmpName, null)
+        parameterRef.type = valueParameter.type
+        aliases[valueParameter] = parameterRef
         targetList += JsParameter(tmpName).apply { hasDefaultValue = valueParameter.hasDefaultValue() }
     }
 

js/js.translator/src/org/jetbrains/kotlin/js/translate/utils/TranslationUtils.java

@@ -545,6 +545,21 @@ public final class TranslationUtils {
             }
         }
 
+        // SAM conversion
+        if ((FunctionTypesKt.isFunctionTypeOrSubtype(from) || FunctionTypesKt.isSuspendFunctionTypeOrSubtype(from))) {
+            ClassifierDescriptor d = to.getConstructor().getDeclarationDescriptor();
+            if (d instanceof ClassDescriptor && ((ClassDescriptor)d).isFun()) {
+                JsName constructorName = context.getInlineableInnerNameForDescriptor(d.getOriginal());
+                if (to.isMarkedNullable()) {
+                    JsConditional c = TranslationUtils.notNullConditional(value, new JsNullLiteral(), context);
+                    c.setThenExpression(new JsNew(new JsNameRef(constructorName), Collections.singletonList(c.getThenExpression())));
+                    value = c;
+                } else {
+                    value = new JsNew(new JsNameRef(constructorName), Collections.singletonList(value));
+                }
+            }
+        }
+
         MetadataProperties.setType(value, to);
         return value;
     }