[JS IR BE] Implement type check for SuspendFunctionN

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIntrinsics.kt

@@ -118,6 +118,7 @@ class JsIntrinsics(private val irBuiltIns: IrBuiltIns, val context: JsIrBackendC
     val isArraySymbol = getInternalFunction("isArray")
     //    val isCharSymbol = getInternalFunction("isChar")
     val isObjectSymbol = getInternalFunction("isObject")
+    val isSuspendFunctionSymbol = getInternalFunction("isSuspendFunction")
 
     val isNumberSymbol = getInternalFunction("isNumber")
     val isComparableSymbol = getInternalFunction("isComparable")

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/TypeOperatorLowering.kt

@@ -42,6 +42,7 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
 
     private val isInterfaceSymbol get() = context.intrinsics.isInterfaceSymbol
     private val isArraySymbol get() = context.intrinsics.isArraySymbol
+    private val isSuspenfFunctionSymbol = context.intrinsics.isSuspendFunctionSymbol
     //    private val isCharSymbol get() = context.intrinsics.isCharSymbol
     private val isObjectSymbol get() = context.intrinsics.isObjectSymbol
 
@@ -209,6 +210,7 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
                 return when {
                     toType.isAny() -> generateIsObjectCheck(argument)
                     toType.isNothing() -> JsIrBuilder.buildComposite(context.irBuiltIns.booleanType, listOf(argument, litFalse))
+                    toType.isSuspendFunctionTypeOrSubtype() -> generateSuspendFunctionCheck(argument, toType)
                     isTypeOfCheckingType(toType) -> generateTypeOfCheck(argument, toType)
 //                    toType.isChar() -> generateCheckForChar(argument)
                     toType.isNumber() -> generateNumberCheck(argument)
@@ -254,6 +256,16 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
 //            private fun generateCheckForChar(argument: IrExpression) =
 //                JsIrBuilder.buildCall(isCharSymbol).apply { dispatchReceiver = argument }
 
+            private fun generateSuspendFunctionCheck(argument: IrExpression, toType: IrType): IrExpression {
+                val arity = (toType.classifierOrFail.owner as IrClass).typeParameters.size - 1 // drop return type
+
+                val irBuiltIns = context.irBuiltIns
+                return JsIrBuilder.buildCall(isSuspenfFunctionSymbol, irBuiltIns.booleanType).apply {
+                    putValueArgument(0, argument)
+                    putValueArgument(1, JsIrBuilder.buildInt(irBuiltIns.intType, arity))
+                }
+            }
+
             private fun generateTypeOfCheck(argument: IrExpression, toType: IrType): IrExpression {
                 val marker = when {
                     toType.isFunctionOrKFunction() -> functionMarker

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/JsClassGenerator.kt

@@ -240,9 +240,21 @@ class JsClassGenerator(private val irClass: IrClass, val context: JsGenerationCo
         metadataLiteral.propertyInitializers += JsPropertyInitializer(JsNameRef(Namer.METADATA_CLASS_KIND), classKind)
 
         metadataLiteral.propertyInitializers += generateSuperClasses()
+
+        if (isCoroutineClass()) {
+            metadataLiteral.propertyInitializers += generateSuspendArity()
+        }
+
         return jsAssignment(JsNameRef(Namer.METADATA, classNameRef), metadataLiteral).makeStmt()
     }
 
+    private fun isCoroutineClass(): Boolean = irClass.superTypes.any { it.isSuspendFunctionTypeOrSubtype() }
+
+    private fun generateSuspendArity(): JsPropertyInitializer {
+        val arity = irClass.declarations.filterIsInstance<IrSimpleFunction>().first { it.isSuspend }.valueParameters.size
+        return JsPropertyInitializer(JsNameRef(Namer.METADATA_SUSPEND_ARITY), JsIntLiteral(arity))
+    }
+
     private fun generateSuperClasses(): JsPropertyInitializer {
         val functionTypeOrSubtype = irClass.defaultType.isFunctionTypeOrSubtype()
         return JsPropertyInitializer(

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/Namer.kt

@@ -35,6 +35,7 @@ object Namer {
     val METADATA_INTERFACES = "interfaces"
     val METADATA_SIMPLE_NAME = "simpleName"
     val METADATA_CLASS_KIND = "kind"
+    val METADATA_SUSPEND_ARITY = "suspendArity"
 
     val KCALLABLE_GET_NAME = "<get-name>"
     val KCALLABLE_NAME = "callableName"