[JS IR BE] Put closure function declaration in container (factory function)

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

@@ -103,6 +103,8 @@ class JsIrBackendContext(
         // TODO: due to name clash those weird suffix is required, remove it once `NameGenerator` is implemented
         private val COROUTINE_SUSPEND_OR_RETURN_JS_NAME = "suspendCoroutineUninterceptedOrReturnJS"
         private val GET_COROUTINE_CONTEXT_NAME = "getCoroutineContext"
+
+        val callableClosureOrigin = object : IrDeclarationOriginImpl("CALLABLE_CLOSURE_DECLARATION") {}
     }
 
     private val internalPackage = module.getPackage(JS_PACKAGE_FQNAME)

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

@@ -218,7 +218,7 @@ class CallableReferenceLowering(val context: JsIrBackendContext) {
                 putValueArgument(1, callableNameConst)
                 putValueArgument(2, JsIrBuilder.buildString(context.irBuiltIns.stringType, getReferenceName(declaration)))
             }
-            Pair(listOf(irVar, irSetName), irVar.symbol)
+            Pair(listOf(refClosureFunction, irVar, irSetName), irVar.symbol)
         }
 
 
@@ -254,7 +254,7 @@ class CallableReferenceLowering(val context: JsIrBackendContext) {
         val setterFunction = propertyReference.setter?.let { buildClosureFunction(it.owner, refGetFunction, propertyReference) }
 
         val additionalDeclarations = generateGetterBodyWithGuard(refGetFunction) {
-            val statements = mutableListOf<IrStatement>()
+            val statements = mutableListOf<IrStatement>(getterDeclaration)
 
             val getterFunctionType = context.builtIns.getFunction(getterFunction.valueParameters.size + 1)
             val type = getterFunctionType.toIrType(symbolTable = context.symbolTable)
@@ -270,6 +270,7 @@ class CallableReferenceLowering(val context: JsIrBackendContext) {
             }
 
             if (setterFunction != null) {
+                statements += setterFunction
                 val setterFunctionType = context.builtIns.getFunction(setterFunction.valueParameters.size + 1)
                 val irSetReference = JsIrBuilder.buildFunctionReference(
                     setterFunctionType.toIrType(symbolTable = context.symbolTable),
@@ -324,7 +325,7 @@ class CallableReferenceLowering(val context: JsIrBackendContext) {
         val getterFunction = buildClosureFunction(context.irBuiltIns.throwIseFun, refGetFunction, propertyReference)
 
         val additionalDeclarations = generateGetterBodyWithGuard(refGetFunction) {
-            val statements = mutableListOf<IrStatement>()
+            val statements = mutableListOf<IrStatement>(getterFunction)
 
             val getterFunctionType = context.builtIns.getFunction(getterFunction.valueParameters.size + 1)
             val type = getterFunctionType.toIrType(symbolTable = context.symbolTable)
@@ -520,7 +521,9 @@ class CallableReferenceLowering(val context: JsIrBackendContext) {
         reference: IrCallableReference
     ): IrFunction {
         val closureName = createClosureInstanceName(declaration)
-        val refClosureDeclaration = JsIrBuilder.buildFunction(closureName, Visibilities.LOCAL).also { it.parent = refGetFunction }
+        val refClosureDeclaration =
+            JsIrBuilder.buildFunction(closureName, Visibilities.LOCAL, origin = JsIrBackendContext.callableClosureOrigin)
+                .also { it.parent = refGetFunction }
 
         // the params which are passed to closure
         val closureParamDeclarations = generateSignatureForClosure(declaration, refGetFunction, refClosureDeclaration, reference)

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

@@ -5,8 +5,10 @@
 
 package org.jetbrains.kotlin.ir.backend.js.transformers.irToJs
 
+import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
 import org.jetbrains.kotlin.ir.backend.js.lower.coroutines.COROUTINE_SWITCH
 import org.jetbrains.kotlin.ir.backend.js.utils.JsGenerationContext
+import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.types.isAny
@@ -16,6 +18,12 @@ import org.jetbrains.kotlin.js.backend.ast.*
 @Suppress("PARAMETER_NAME_CHANGED_ON_OVERRIDE")
 class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsStatement, JsGenerationContext> {
 
+    override fun visitFunction(declaration: IrFunction, data: JsGenerationContext) = JsEmpty.also {
+        assert(declaration.origin == JsIrBackendContext.callableClosureOrigin) {
+            "The only possible Function Declarartion is one composed in Callable Reference Lowering"
+        }
+    }
+
     override fun visitBlockBody(body: IrBlockBody, context: JsGenerationContext): JsStatement {
         return JsBlock(body.statements.map { it.accept(this, context) })
     }