Bug #15647: Disallow "in" as a keyword argument name

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin17]
• Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN

[localhostdotdev (localhost .dev)]

"in" is a reserved keyword and thus can't be accessed directly anyway.

e.g. the following is a syntax error:

def m(in:); p in; end; m(in: 1)

And as usual, doing in = 1 doesn't work.

"in" could still be passed as a keyword argument if using some kind of catch-all, e.g. m(args), m(*args), etc.

Source: https://twitter.com/drbrain/status/1104152696339087361

[drbrain (Eric Hodel)]

This would break the Kernel#spawn family's backward compatibility make wrapping methods in this family harder than it already is, as you can work around this with Binding#local_variable_get.

I think this should be rejected.

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Status changed from Open to Rejected

It is known that reserved words can be keyword arguments.
And Binding#local_variable_get has been added for that purpose, if argument for instance.