[JS IR BE] Fix varargs for inline arrays

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

@@ -14,6 +14,8 @@ import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
 import org.jetbrains.kotlin.ir.declarations.impl.IrExternalPackageFragmentImpl
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.symbols.impl.IrExternalPackageFragmentSymbolImpl
+import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeBuilder
+import org.jetbrains.kotlin.ir.types.impl.buildSimpleType
 import org.jetbrains.kotlin.ir.types.isLong
 import org.jetbrains.kotlin.ir.util.constructors
 import org.jetbrains.kotlin.ir.util.findDeclaration
@@ -244,7 +246,7 @@ class JsIntrinsics(private val irBuiltIns: IrBuiltIns, val context: JsIrBackendC
 
     val primitiveArrayConcat = getInternalWithoutPackage("primitiveArrayConcat")
 
-    val jsArraySlice = unOp("slice")
+    val jsArraySlice = defineJsSliceIntrinsic().symbol
 
     val jsBind = defineJsBindIntrinsic()
 
@@ -322,6 +324,27 @@ class JsIntrinsics(private val irBuiltIns: IrBuiltIns, val context: JsIrBackendC
             externalPackageFragment.declarations += it
         }
 
+    private fun defineJsSliceIntrinsic(): IrSimpleFunction {
+        val typeParameter = JsIrBuilder.buildTypeParameter(Name.identifier("A"), 0, true).apply {
+            superTypes += irBuiltIns.anyType
+        }
+        val type = IrSimpleTypeBuilder().run {
+            classifier = typeParameter.symbol
+            buildSimpleType()
+        }
+
+        return JsIrBuilder.buildFunction(
+            "slice",
+            returnType = type,
+            parent = externalPackageFragment,
+            origin = JsLoweredDeclarationOrigin.JS_INTRINSICS_STUB
+        ).also {
+            it.typeParameters += typeParameter.also { t -> t.parent = it }
+            it.valueParameters += JsIrBuilder.buildValueParameter("a", 0, type).also { v -> v.parent = it }
+            externalPackageFragment.declarations += it
+        }
+    }
+
     private fun defineSetJSPropertyIntrinsic() =
         JsIrBuilder.buildFunction(
             "\$setJSProperty\$",

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

@@ -58,7 +58,7 @@ private class VarargTransformer(
     fun IrExpression.unboxInlineClassIfNeeded(): IrExpression {
         val inlinedClass = type.getInlinedClass() ?: return this
         val field = getInlineClassBackingField(inlinedClass)
-        return IrGetFieldImpl(startOffset, endOffset, field.symbol, inlinedClass.defaultType, this)
+        return IrGetFieldImpl(startOffset, endOffset, field.symbol, field.type, this)
     }
 
     fun IrExpression.boxInlineClassIfNeeded(inlineClass: IrClass?) =
@@ -121,28 +121,25 @@ private class VarargTransformer(
 
         // vararg with a single segment => no need to concatenate
         if (segments.size == 1) {
-            return if (expression.elements.any { it is IrSpreadElement }) {
-                // Single spread operator => need to copy the array
+            val segment = segments.first()
+            val argument = if (expression.elements.any { it is IrSpreadElement }) {
                 IrCallImpl(
                     expression.startOffset,
                     expression.endOffset,
                     expression.type,
                     context.intrinsics.jsArraySlice
                 ).apply {
-                    putValueArgument(0, segments.first())
+                    putTypeArgument(0, expression.type)
+                    putValueArgument(0, segment)
                 }
-            } else {
-                val res = segments.first()
-                return if (needUnboxing)
-                    res.boxInlineClassIfNeeded(arrayInlineClass!!)
-                else
-                    res
-            }
+            } else segment
+
+            return if (needUnboxing) argument.boxInlineClassIfNeeded(arrayInlineClass!!) else argument
         }
 
         val arrayLiteral =
             segments.toArrayLiteral(
-                IrSimpleTypeImpl(context.intrinsics.array, false, emptyList(), emptyList()),
+                IrSimpleTypeImpl(context.intrinsics.array, false, emptyList(), emptyList()), // TODO: Substitution
                 context.irBuiltIns.anyType
             )
 

compiler/testData/codegen/box/unsignedTypes/varargsOfUnsignedTypes.kt

@@ -1,7 +1,6 @@
 // IGNORE_BACKEND: JVM_IR
 // WITH_RUNTIME
 // KJS_WITH_FULL_RUNTIME
-// IGNORE_BACKEND: JS_IR
 
 fun uint(vararg us: UInt): UIntArray = us
 

js/js.translator/testData/box/expression/function/varargUInt.kt

@@ -1,5 +1,4 @@
 // LANGUAGE_VERSION: 1.3
-// IGNORE_BACKEND: JS_IR
 // KJS_WITH_FULL_RUNTIME
 // EXPECTED_REACHABLE_NODES: 1566
 package foo