Ruby

[ruby/prism] Fix a diagnostic incompatibility

This PR fixes a diagnostic incompatibility when using no anonymous keyword rest parameter:

foo(**)

Note, although the actual update applies only to the foo(**) case, for reference,
foo(*) and `foo(&) are also mentioned below.

Ruby (Expected)¶

$ ruby -cve 'foo(*)'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
-e:1: no anonymous rest parameter
-e: compile error (SyntaxError)

$ ruby -cve 'foo(**)'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
-e:1: no anonymous keyword rest parameter
-e: compile error (SyntaxError)

$ ruby -cve 'foo(&)'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
-e:1: no anonymous block parameter
-e: compile error (SyntaxError)

Prism (Actual)¶

Before:

$ bundle exec ruby -Ilib -rprism -wve 'p Prism.parse("foo(*)").errors'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
[#<Prism::ParseError @type=:argument_no_forwarding_star @message="unexpected `*` when the parent method is not forwarding"
@location=#<Prism::Location @start_offset=4 @length=1 start_line=1> @level=:fatal>]

$ bundle exec ruby -Ilib -rprism -wve 'p Prism.parse("foo(**)").errors'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
[#<Prism::ParseError @type=:expect_expression_after_splat_hash @message="expected an expression after `**` in a hash"
@location=#<Prism::Location @start_offset=4 @length=2 start_line=1> @level=:fatal>]

$ bundle exec ruby -Ilib -rprism -wve 'p Prism.parse("foo(&)").errors'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
[#<Prism::ParseError @type=:argument_no_forwarding_amp @message="unexpected `&` when the parent method is not forwarding"
@location=#<Prism::Location @start_offset=4 @length=1 start_line=1> @level=:fatal>]

After:

$ bundle exec ruby -Ilib -rprism -wve 'p Prism.parse("foo(*)").errors'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
[#<Prism::ParseError @type=:argument_no_forwarding_star @message="unexpected `*` when the parent method is not forwarding"
@location=#<Prism::Location @start_offset=4 @length=1 start_line=1> @level=:fatal>]

$ bundle exec ruby -Ilib -rprism -wve 'p Prism.parse("foo(**)").errors'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
[#<Prism::ParseError @type=:argument_no_forwarding_star_star @message="unexpected `**` when the parent method is not forwarding"
@location=#<Prism::Location @start_offset=4 @length=2 start_line=1> @level=:fatal>]

$ bundle exec ruby -Ilib -rprism -wve 'p Prism.parse("foo(&)").errors'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
[#<Prism::ParseError @type=:argument_no_forwarding_amp @message="unexpected `&` when the parent method is not forwarding"
@location=#<Prism::Location @start_offset=4 @length=1 start_line=1> @level=:fatal>]

https://github.com/ruby/prism/commit/633c9d9fd4