From 72a613bc6a7ac389e359fa9f0926ebfe395a9390 Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Tue, 19 Mar 2024 01:56:30 +0900
Subject: [PATCH] [ruby/prism] Fix a diagnostic incompatibility for
 `Prism::Translation::Parser`

This PR fixes a diagnostic incompatibility for `Prism::Translation::Parser` when using constant argument:

```ruby
def foo(A)
end
```

## Parser gem (Expected)

Displays `formal argument cannot be a constant (Parser::SyntaxError)`:

```console
$ bundle exec ruby -Ilib -rparser/ruby33 -ve 'p Parser::Ruby33.parse("def foo(A) end")'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
(string):1:9: error: formal argument cannot be a constant
(string):1: def foo(A) end
(string):1:         ^
/Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/diagnostic/engine.rb:72:
in `process': formal argument cannot be a constant (Parser::SyntaxError)
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/base.rb:274:in `diagnostic'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/ruby33.rb:12177:in `_reduce_663'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/racc-1.7.3/lib/racc/parser.rb:267:in `_racc_do_parse_c'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/racc-1.7.3/lib/racc/parser.rb:267:in `do_parse'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/base.rb:190:in `parse'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/base.rb:33:in `parse'
        from -e:1:in `<main>'
```

## `Prism::Translation::Parser` (Actual)

Previously, the error messages displayed by the Parser gem were different.

Before:

```console
$ bundle exec ruby -Ilib -rprism -rprism/translation/parser33 -ve 'Prism::Translation::Parser33.parse("def foo(A) end")'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
(string):1:9: error:
(string):1: def foo(A) end
(string):1:         ^
/Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/diagnostic/engine.rb:72:
in `process': Parser::SyntaxError (Parser::SyntaxError)
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:218:in `block in unwrap'
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:216:in `each'
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:216:in `unwrap'
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:49:in `parse'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/base.rb:33:in `parse'
        from -e:1:in `<main>'
```

After:

```console
$ bundle exec ruby -Ilib -rprism -rprism/translation/parser33 -ve 'Prism::Translation::Parser33.parse("def foo(A) end")'
ruby 3.3.0 (2023-12-25 revision https://github.com/ruby/prism/commit/5124f9ac75) [x86_64-darwin22]
(string):1:9: error: formal argument cannot be a constant
(string):1: def foo(A) end
(string):1:         ^
/Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/diagnostic/engine.rb:72:
in `process': formal argument cannot be a constant (Parser::SyntaxError)
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:218:in `block in unwrap'
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:216:in `each'
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:216:in `unwrap'
        from /Users/koic/src/github.com/ruby/prism/lib/prism/translation/parser.rb:49:in `parse'
        from /Users/koic/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/parser-3.3.0.5/lib/parser/base.rb:33:in `parse'
        from -e:1:in `<main>'
```

https://github.com/ruby/prism/commit/4f2af88520
---
 lib/prism/translation/parser.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/prism/translation/parser.rb b/lib/prism/translation/parser.rb
index 6a2a9bbf24..48a198504b 100644
--- a/lib/prism/translation/parser.rb
+++ b/lib/prism/translation/parser.rb
@@ -124,7 +124,7 @@ module Prism
         when :argument_block_multi
           Diagnostic.new(:error, :block_and_blockarg, {}, diagnostic_location, [])
         when :argument_formal_constant
-          Diagnostic.new(:error, :formal_argument, {}, diagnostic_location, [])
+          Diagnostic.new(:error, :argument_const, {}, diagnostic_location, [])
         when :argument_formal_class
           Diagnostic.new(:error, :argument_cvar, {}, diagnostic_location, [])
         when :argument_formal_global