[webkit-changes] [WebKit/WebKit] 133e01: [JSC] Block-level function declarations shouldn't ...

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  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 133e011511b5b82e015c005ac961fab21b4ce825
      https://github.com/WebKit/WebKit/commit/133e011511b5b82e015c005ac961fab21b4ce825
  Author: Alexey Shvayka <ashvayka at apple.com>
  Date:   2023-09-29 (Fri, 29 Sep 2023)

  Changed paths:
    M JSTests/test262/expectations.yaml
    M LayoutTests/js/parser-syntax-check-expected.txt
    M LayoutTests/js/script-tests/parser-syntax-check.js
    M Source/JavaScriptCore/parser/Parser.h

  Log Message:
  -----------
  [JSC] Block-level function declarations shouldn't be allowed to shadow `var` bindings
https://bugs.webkit.org/show_bug.cgi?id=262330
<rdar://problem/116202546>

Reviewed by Yusuke Suzuki and Justin Michaud.

This change aligns non-`var` case of declareFunction() with declareLexicalVariable() to throw a
SyntaxError if a block-level function declaration would shadow a `var` binding, previously declared
in this or in a nested scope.

The early error is specified here [1], while the fact of FunctionDeclaration being lexical is
described here [2].

Aligns JSC with V8 and SpiderMonkey.

[1]: https://tc39.es/ecma262/#sec-block-static-semantics-early-errors
[2]: https://tc39.es/ecma262/#sec-static-semantics-lexicallydeclarednames

* JSTests/test262/expectations.yaml: Mark 24 tests as passing.
* LayoutTests/js/parser-syntax-check-expected.txt:
* LayoutTests/js/script-tests/parser-syntax-check.js:
* Source/JavaScriptCore/parser/Parser.h:
(JSC::Scope::declareFunction):

Canonical link: https://commits.webkit.org/268634@main