Lexical redeclarations in block- and switch-statements #1023
Conversation
| ---*/ | ||
|
|
||
|
|
||
| switch (0) { case 1: async function f() {} default: function f() {} } |
There was a problem hiding this comment.
@anba, I'm having a hard time to find the spec parts saying the function (and async function) declaration names are added to the Lexical Scope.
Can you help me pointing to where I'm missing there? Thanks.
There was a problem hiding this comment.
I'm taking the table 27 as the only reference for it. The [[Environment]] as the lexical environment where the function is bound to.
There was a problem hiding this comment.
In https://tc39.github.io/ecma262/#sec-switch-statement-static-semantics-lexicallydeclarednames, all lexically declared names from the different case clauses are combined.
For each case clause, the LexicallyDeclaredNames definition from https://tc39.github.io/ecma262/#sec-block-static-semantics-lexicallydeclarednames applies, which has:
StatementListItem : Declaration
- Return the BoundNames of Declaration.
And in https://tc39.github.io/ecma262/#prod-Declaration we've got:
Declaration[Yield, Await] : HoistableDeclaration[?Yield, ?Await, ~Default]
And in https://tc39.github.io/ecma262/#prod-HoistableDeclaration:
HoistableDeclaration[Yield, Await, Default] : FunctionDeclaration[?Yield, ?Await, ?Default]
And the BoundNames of a FunctionDeclaration is its BindingIdentifier https://tc39.github.io/ecma262/#sec-function-definitions-static-semantics-boundnames.
And there's also B3.3.5 (https://tc39.github.io/ecma262/#sec-switch-duplicates-allowed-static-semantics) which allows duplicate FunctionDeclarations in sloppy mode in switch-statements.
There was a problem hiding this comment.
Thank you very much! I really appreciate as this part has got tricky for me.
| if len(includes): | ||
| lines += ['includes: ' + yaml.dump(includes).strip()] | ||
|
|
||
| if case_values['meta'].get('negative'): | ||
| if self.attribs['meta'].get('negative'): | ||
| raise Exception('Cannot specify negative in case and template file') |
Improves test coverage for lexical redeclarations in block- and switch-statements.
To reduce the number of case/template files, I've modified the test file generator to allow to specify the "negative" tag in template files.
Ref: https://bugzilla.mozilla.org/show_bug.cgi?id=1359575