Bug #21927: Prism: misleading error message for forwarding in lambda argument

• Status: Open
• Assignee: prism
• Target version: -
• ruby -v: d256629bf9
• Backport: 3.2: DONTNEED, 3.3: DONTNEED, 3.4: REQUIRED, 4.0: REQUIRED

[nobu (Nobuyoshi Nakada)]

Even in a forwarding method:

$ ruby --parser=prism -e 'def m(...) ->(...){}; end'
-e: -e:1: syntax error found (SyntaxError)
> 1 | def m(...) ->(...){}; end
    |               ^~~ unexpected ... when the parent method is not forwarding

This message is proper for method arguments:

$ ruby --parser=prism -e 'def m() p(...); end'
-e: -e:1: syntax error found (SyntaxError)
> 1 | def m() p(...); end
    |           ^~~ unexpected ... when the parent method is not forwarding

The message from parse.y is different; "unexpected ... in lambda argument":

$ ruby --parser=parse.y -e 'def m(...) ->(...){}; end'
-e:1: unexpected ... in lambda argument
def m(...) ->(...){}; end
ruby: compile error (SyntaxError)

[Earlopain (Earlopain _)]

https://github.com/ruby/prism/pull/3947