Support #detailed_message for RBS::ParsingError

[ksss]

Exception#detailed_message is a new feature supported from Ruby v3.2.0 and above.
https://bugs.ruby-lang.org/issues/18564

I would like to propose that this feature be applied to RBS.

CLI usage.

$ ruby -v
ruby 3.2.0preview2 (2022-09-09 master 35cfc9a3bb) [arm64-darwin21]

$ cat parsing_error.rbs
class Foo
  deff aaa: () -> void
end

$ rbs -I parsing_error.rbs validate --silent
/Users/ksss/src/github.com/ksss/rbs/lib/rbs/parser_aux.rb:17:in `_parse_signature': parsing_error.rbs:2:2...2:6: Syntax error: unexpected token for class/module declaration member, token=`deff` (tLIDENT) (RBS::ParsingError)

    deff aaa: () -> void
    ^^^^

	from /Users/ksss/src/github.com/ksss/rbs/lib/rbs/parser_aux.rb:17:in `parse_signature'
	from /Users/ksss/src/github.com/ksss/rbs/lib/rbs/environment_loader.rb:162:in `block (2 levels) in each_decl'
	from /Users/ksss/src/github.com/ksss/rbs/lib/rbs/environment_loader.rb:132:in `each_file'
        (snip)

Script usage.

$ bundle exec irb -r rbs
irb(main):001:0> RBS::Parser.parse_type("singleton(foo)")
/Users/ksss/src/github.com/ksss/rbs/lib/rbs/parser_aux.rb:7:in `_parse_type': a.rbs:1:10...1:13: Syntax error: expected one of class/module/constant name, token=`foo` (tLIDENT) (RBS::ParsingError)

  singleton(foo)
            ^^^

	from /Users/ksss/src/github.com/ksss/rbs/lib/rbs/parser_aux.rb:7:in `parse_type'
	from (irb):1:in `<main>'
        (snip)

This feature is inspired by error_highlight.

Scope is limited to Ruby 3.2.0 or later and ParsingError combinations.

To support Ruby 3.1 or earlier, incompatible changes need to be made, so they are out of scope.

It is likely that other errors could also be supported, but I have limited the scope to ParsingError only to keep the PR scope small.

[soutaro]

@ksss Thank you for this PR. Looks great!

Could you explain about the incompatible changes to support Ruby 3.1? It's totally fine to provide this feature for only 3.2+, but introducing incompatible changes also would be ok when we release a major update -- RBS 3.0.

[ksss]

An incompatibility in Ruby 3.1 and earlier is a change in the #to_s of each error class.
The return value of #to_s will be multi-line and tests for matching error messages will fail.

e.g.

rbs/test/rbs/parser_test.rb

Lines 494 to 497 in 57c07bb

	assert_equal(
	'test.rbs:1:13...1:15: Syntax error: comma delimited type list is expected, token=`::` (pCOLON2)',
	exn.message
	)

More detailed explanation of the incompatibility can be found here.
https://bugs.ruby-lang.org/issues/18564#Motivation

However, since RBS is a relatively new project, the impact may be minimal.

If we accept this incompatibility, we would put in a branch like error_highlight.

https://github.com/ruby/error_highlight/blob/5275078dc6f33148c0241160bed0b43753aae863/lib/error_highlight/core_ext.rb#L11-L36