A question about uninitialized variables · chakra-core/ChakraCore#6516

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BugSeverity: 3help wanted

説明

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?

コントリビューターガイド

技術スタック: javascript
領域: backend
Issue 種別: bug
難度: 4
推定時間: 3-5 days
活動状況: stale
明確さ: clear
前提条件: JavaScript engine internalsECMAScript specificationC++
初心者向け度: 20
調査方針: 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.