build(deps-dev): bump rbs from 4.0.3 to 4.2.0

[dependabot]

Bumps rbs from 4.0.3 to 4.2.0.

Release notes

Sourced from rbs's releases.

4.2.0

Release note

RBS 4.2 accepts non-ASCII characters in identifiers. Method names, instance variable names and parameter names can be written in any script, and other names may contain non-ASCII characters as long as they start with an ASCII letter, which is what tells a constant from a method name.

class Greeter
  @挨拶: String
def こんにちは: () -> String
end

The parser and the AST support Ruby-style ... forwarding parameters in method types, but the layers built on top of the parser do not yet. The syntax is disabled by default in 4.2 and is not enabled by the public RBS::Parser API, so it cannot be used in regular RBS signatures yet.

Ruby 3.2 reached EOL on 2026-04-01, and this release requires Ruby 3.3 or later. Applications on 3.2 stay on the 4.1 line.

Signature updates

Updated classes/modules/methods: ERB, ERB::DefMethod, IO, Monitor, MonitorMixin::ConditionVariable, Singleton, StringIO, Zlib::GzipFile, Zlib::GzipWriter

• Replace deterministic untyped return types with concrete types (#2966)
• Declare Singleton::SingletonInstanceMethods (#3037)

Language updates

• Gate forwarding parameter syntax behind parser option (#3087)
• Support non-ASCII identifiers (#3082)
• Support forwarding parameters in method types (#3042)

Library changes

• Drop runtime support for Ruby 3.2 (#3095)
• Stop the lexer reading past the end of a byte_range (#3040)
• Exclude CR from comment tokens to fix an off-by-one Location#end_line on CRLF files (#3069)
• Handle the NULL parser in the WebAssembly shim (#3085)
• Reject a byte position the lexer cannot start on (#3083)
• Don't use Clang nullability qualifiers in strict ISO C mode (#3074)
• Avoid eagerly inspecting call traces in type assertions (#3073)
• Fix TypeParam.rename to substitute variables in bounds and default types (#3068)
• Extract per-declaration type param alignment into entry-level align_params (#3070)
• Align type params across declarations in module-self types and superclass validation (#3067)
• Build the wasm module with -DNDEBUG (#3066)
• Rename NODISCARD macro to RBS_NODISCARD (#3065)

Miscellaneous

• Omit forwarding parameter tests on JRuby (#3092)
• Skip JSON 2-only tests with JSON 3 (#3084)
• Pin GitHub Actions to commit hashes (#3020)

... (truncated)

Changelog

Sourced from rbs's changelog.

4.2.0 (2026-08-23)

RBS 4.2 accepts non-ASCII characters in identifiers. Method names, instance variable names and parameter names can be written in any script, and other names may contain non-ASCII characters as long as they start with an ASCII letter, which is what tells a constant from a method name.

class Greeter
  @挨拶: String
def こんにちは: () -> String
end

The parser and the AST support Ruby-style ... forwarding parameters in method types, but the layers built on top of the parser do not yet. The syntax is disabled by default in 4.2 and is not enabled by the public RBS::Parser API, so it cannot be used in regular RBS signatures yet.

Ruby 3.2 reached EOL on 2026-04-01, and this release requires Ruby 3.3 or later. Applications on 3.2 stay on the 4.1 line.

Signature updates

Updated classes/modules/methods: ERB, ERB::DefMethod, IO, Monitor, MonitorMixin::ConditionVariable, Singleton, StringIO, Zlib::GzipFile, Zlib::GzipWriter

• Replace deterministic untyped return types with concrete types (#2966)
• Declare Singleton::SingletonInstanceMethods (#3037)

Language updates

• Gate forwarding parameter syntax behind parser option (#3087)
• Support non-ASCII identifiers (#3082)
• Support forwarding parameters in method types (#3042)

Library changes

• Drop runtime support for Ruby 3.2 (#3095)
• Stop the lexer reading past the end of a byte_range (#3040)
• Exclude CR from comment tokens to fix an off-by-one Location#end_line on CRLF files (#3069)
• Handle the NULL parser in the WebAssembly shim (#3085)
• Reject a byte position the lexer cannot start on (#3083)
• Don't use Clang nullability qualifiers in strict ISO C mode (#3074)
• Avoid eagerly inspecting call traces in type assertions (#3073)
• Fix TypeParam.rename to substitute variables in bounds and default types (#3068)
• Extract per-declaration type param alignment into entry-level align_params (#3070)
• Align type params across declarations in module-self types and superclass validation (#3067)
• Build the wasm module with -DNDEBUG (#3066)
• Rename NODISCARD macro to RBS_NODISCARD (#3065)

Miscellaneous

• Omit forwarding parameter tests on JRuby (#3092)
• Skip JSON 2-only tests with JSON 3 (#3084)
• Pin GitHub Actions to commit hashes (#3020)

... (truncated)

Commits

• 8aee3b6 Merge pull request #3096 from ruby/claude/4-2-release-tasks-h6thzx
• 6f97c87 Version 4.2.0
• 03d4281 Merge pull request #2966 from zonuexe/fix/concrete-untyped-returns
• bdecacf Make putc signatures type-preserving overloads
• 69539d6 Replace deterministic untyped return types with concrete types
• c9957e4 Merge pull request #3037 from infiton/rxc/declare-singleton-instance-methods
• 1f40487 Merge pull request #3095 from ruby/claude/4-2-release-tasks-h6thzx
• e721ad1 Drop runtime support for Ruby 3.2
• 584b4cf Merge pull request #3092 from ruby/claude/rbs-ci-failure-sinnfd
• e709673 Merge pull request #3090 from ruby/claude/release-4-2-0-pre-1-vyzb7g
• Additional commits viewable in compare view

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