Sourced from rbs's releases.

4.0.2

Release note

Library changes

rbs collection

• Fix: pathname not written to lockfile. (#2889)

Miscellaneous

• Fix test failure on Windows in ruby/ruby (#2900)
• Fix test for Ruby 4.1 (#2899)

4.0.0

Release note

RBS 4.0 ships with experimental RBS inline syntax support, allowing you to write type annotations directly in Ruby source files. See https://github.com/ruby/rbs/blob/HEAD/docs/inline.md for the syntax details.

class Calculator
  # @rbs (Integer, Integer) -> Integer
  def add(a, b) = a + b
end

Note: RBS inline is still experimental and may change in future releases.

This release also introduces two language changes: type argument support for singleton types (singleton(T)[S]) mainly for Sorbet integration, and generic type parameter lower bounds (T < S).

Signature updates

Updated classes/modules/methods: Addrinfo, Array, BasicObject, BigDecimal, Binding, CGI, Comparable, Complex, Digest::SHA2, Encoding::Converter, Enumerable, Enumerator, Enumerator::ArithmeticSequence, Enumerator::Lazy, Fiber, File, FileUtils, Float, Hash, IO, IO::TimeoutError, Integer, JSON, Kernel, Kconv, Math, Method, Minitest, Module, Numeric, ObjectSpace, Open3, OpenURI, OptionParser, PStore, Pathname, Proc, Process::Status, Psych, Ractor, Random, Random::Formatter, Range, Rational, RBS::Unnamed::TopLevelSelfClass, Ripper::Lexer::Elem, Ruby, RubyVM, SecureRandom, Set, Socket, String, StringScanner, TCPSocket, Thread, URI, URI::Generic, Zlib::GzipReader, Zlib::GzipWriter

• Remove deprecated types (#2880)
• Add type RBS::Unnamed::TopLevelSelfClass to core (#2362)
• Graduate bundled gems from Ruby v4.0 (#2852)
• stdlib: Add missing Psych methods and exception classes (#2850)
• Add variants with positional argument to Hash#transform_keys (#2848)
• add extra kwarg options for File#initialize and derivatives (#2798)
• pstore: fixes types, treat it as a collection (#2806)
• Add signatures for {Module,Proc}#ruby2_keywords (#2805)
• Make Zlib::GzipWriter.new level and strategy parameters optional (#2810)
• URI.(s) does string coercion (#2825)
• Fix String#append_as_bytes to accept Integer (#2817)
• [Comparable] Add in Comparable::_CompareToZero (#2697)
• [Kernel] Add Kernel.trace_var and Kernel.untrace_var (#2682)
• Add signature for Module#method_undefined (#2804)
• Fix Zlib::GzipWriter signatures (#2803)
• GzipWriter#initialize only takes 1 required positional arg (#2799)

... (truncated)

Sourced from rbs's changelog.

4.0.2 (2026-03-25)

Library changes

rbs collection

• Fix: pathname not written to lockfile. (#2889)

Miscellaneous

• Fix test failure on Windows in ruby/ruby (#2900)
• Fix test for Ruby 4.1 (#2899)

4.0.1 (2026-03-23)

This is a minor release to fix Ruby CI failure, which was caused by symlinks included in the rust directory.

Library changes

• Fix () -> (void) being rejected as SyntaxError (#2884)

Miscellaneous

• Drop crates (#2887)
• Add newline at eof (#2885)

4.0.0 (2026-03-16)

RBS 4.0 ships with experimental RBS inline syntax support, allowing you to write type annotations directly in Ruby source files. See https://github.com/ruby/rbs/blob/master/docs/inline.md for the syntax details.

class Calculator
  # @rbs (Integer, Integer) -> Integer
  def add(a, b) = a + b
end

Note: RBS inline is still experimental and may change in future releases.

This release also introduces two language changes: type argument support for singleton types (singleton(T)[S]) mainly for Sorbet integration, and generic type parameter lower bounds (T < S).

Signature updates

Updated classes/modules/methods: Addrinfo, Array, BasicObject, BigDecimal, Binding, CGI, Comparable, Complex, Digest::SHA2, Encoding::Converter, Enumerable, Enumerator, Enumerator::ArithmeticSequence, Enumerator::Lazy, Fiber, File, FileUtils, Float, Hash, IO, IO::TimeoutError, Integer, JSON, Kernel, Kconv, Math, Method, Minitest, Module, Numeric, ObjectSpace, Open3, OpenURI, OptionParser, PStore, Pathname, Proc, Process::Status, Psych, Ractor, Random, Random::Formatter, Range, Rational, RBS::Unnamed::TopLevelSelfClass, Ripper::Lexer::Elem, Ruby, RubyVM, SecureRandom, Set, Socket, String, StringScanner, TCPSocket, Thread, URI, URI::Generic, Zlib::GzipReader, Zlib::GzipWriter

• Remove deprecated types (#2880)
• Add type RBS::Unnamed::TopLevelSelfClass to core (#2362)
• Graduate bundled gems from Ruby v4.0 (#2852)
• stdlib: Add missing Psych methods and exception classes (#2850)
• Add variants with positional argument to Hash#transform_keys (#2848)

... (truncated)

• ec51456 Merge pull request #2902 from ruby/version-4.0.2
• fa619f2 Version 4.0.2
• d74c74c Copy CHANGELOG for 3.10.4
• 5b0dcab Merge pull request #2900 from ruby/fix-windows-test
• 7504ccd unsetenv_others: false
• 2a2bb9e Use echo instead of env for Windows
• 63313dd Merge pull request #2889 from ksss/pathname-collection
• 1ef7f41 Merge branch 'master' into pathname-collection
• 9e81252 Merge pull request #2899 from ruby/fix-ruby-head-test
• a0581b9 Fix test for Ruby 4.1
• Additional commits viewable in compare view