1618526 - searchInEnclosingScope() doesn't need to check for declared parameters in non-simple parameter lists

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P1)

Description

[André Bargull [:anba]]

Duplicate parameters are only allowed for non-strict function with simple parameter lists. Furthermore the function must neither be an arrow nor a method function. A parameter list is non-simple if one of the following applies:

• It contains parameter default expressions.
• It contains destructuring parameters.
• It contains rest arguments.

EmitterScope::searchInEnclosingScope() is currently searching for duplicate parameters in non-strict without default parameters (!script->strict() && !script->functionHasParameterExprs()), but unless I'm misinterpreting this code, we should also be able to skip the duplicate parameter check when destructuring or rest parameters are present. (Or when the function is an arrow or method function, except we don't have a script flag at hand to determine the function kind.)

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1618526: Don't check for duplicate parameters when duplicates aren't allowed in the function context. r=jandem!

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f3fdc0edd2c4
Don't check for duplicate parameters when duplicates aren't allowed in the function context. r=jandem

Comment 3

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/f3fdc0edd2c4