fix: rest element should deoptimize parameter values

src/ast/nodes/shared/FunctionBase.ts

@@ -18,7 +18,7 @@ import type ExportDefaultDeclaration from '../ExportDefaultDeclaration';
 import Identifier from '../Identifier';
 import * as NodeType from '../NodeType';
 import RestElement from '../RestElement';
-import type SpreadElement from '../SpreadElement';
+import SpreadElement from '../SpreadElement';
 import type VariableDeclarator from '../VariableDeclarator';
 import { Flag, isFlagSet, setFlag } from './BitFlags';
 import type { ExpressionEntity, LiteralValueOrUnknown } from './Expression';
@@ -100,6 +100,9 @@ export default abstract class FunctionBase extends NodeBase {
 				const parameter = this.params[position];
 				// Only the "this" argument arg[0] can be null
 				const argument = args[position + 1]!;
+				if (argument instanceof SpreadElement) {
+					this.deoptimizeParameterVariableValues();
+				}
 				if (hasRest || parameter instanceof RestElement) {
 					hasRest = true;
 					argument.deoptimizePath(UNKNOWN_PATH);

test/function/samples/rest-element-argument/_config.js

@@ -0,0 +1,3 @@
+module.exports = defineTest({
+	description: 'restelement argument should deoptimize parameter value'
+});

test/function/samples/rest-element-argument/main.js

@@ -0,0 +1,21 @@
+let hasArg0 = false;
+let hasArg1 = false;
+let hasArg2 = false;
+
+function foo(arg0, arg1, arg2) {
+  if (arg0) {
+    hasArg0 = true;
+  }
+  if (arg1) {
+    hasArg1 = true;
+  }
+  if (arg2) {
+    hasArg2 = true;
+  }
+}
+
+foo(...['arg0', 'arg1']);
+
+assert.equal(hasArg0, true);
+assert.equal(hasArg1, true);
+assert.equal(hasArg2, false);