chakra-core/ChakraCore

A question about uninitialized variables

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#6,516 创建于 2020年10月5日

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 (5 评论) (0 反应) (0 负责人)JavaScript (9,000 star) (1,374 fork)batch import
BugSeverity: 3help wanted

描述

Version

chakra-1_11_22

Test case
var h = function f(a0 = function () {
  a2;
}(), a2) {
};
h();
Execution steps
./ChakraCore/out/Debug/ch testcase.js
Output
Expected behavior
ReferenceError: can't access lexical declaration `a2' before initialization
Description

When executing this test case, a2 is not initialized before the call, other engines (such as v8, spiderMonkey, JavaScriptCore, etc.) threw a ReferenceError, but chakra did not do so. Is this a different implementation of chakra?

贡献者指南

技术栈
javascript
领域
backend
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
4
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
3-5 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
JavaScript engine internalsECMAScript specificationC++
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
20
研究方向
Investigate the handling of lexical declarations in default parameters in ChakraCore's parser and interpreter. Compare with ECMAScript specification to identify where the expected ReferenceError should be thrown. Look for existing tests in the repository related to temporal dead zone.
A question about uninitialized variables · chakra-core/ChakraCore#6516 | Good First Issue