Release Note 3.9

Some of the highlights in RBS 3.9 are:

• Add resolve-type-names: false magic comment (#2234)
• Annotations on constants, globals, class/module aliases (#2302)
• Annotation processing overhaul (#2301)
• Improved validation (#2237, #2241, #2289, #2294, #2300)
• Untyped proc type can have self type hint (#2325)
• Replace %a{steep:deprecated} with %a{deprecated} (#2328)

You can install it with $ gem install rbs or using Bundler.

gem 'rbs', '~> 3.9.0'

Read the CHANGELOG for the details.

Add resolve-type-names: false magic comment

PR: #2234

You can add resolve-type-names: false magic comment at the beginning of RBS files to skip type name resolution. This makes RBS file loading faster, typically for generated RBS files where the type names can be identified already.

# resolve-type-names: false

class Foo
  def foo: () -> ::String         # ::String should be used instead of String
end

Annotations on constants, globals, class/module aliases

PR: #2302

Constant declarations, global declarations, and class/module alias declarations can be annotated.

%a{deprecated}
VERSION: String

%a{deprecated}
$NAME: String

%a{deprecated}
module Foo = Kernel

Annotation processing overhaul

PR: #2301

Annotations given to method definition resets to its aliases.

class Test
  %a{deprecated}
  def foo: %a{implicitly-returns-nil} () -> String

  alias bar foo
end

In this example, %a{deprecated} annotation is given to the def syntax of foo, while the %a{implicitly-returns-nil} annotation is attached to the method overload. Because the annotation on def syntax resets on alias, bar doesn't have %a{deprecated} annotation. However, %a{implicitly-returns-nil} is attached the overload, and the method overload in bar inherits the annotations.

Annotations on class/module aliases also resets the original annotations.

%a{deprecated}
class Test
end

class Test2 = Test

::Test is deprecated but ::Test2 is not.

Note that RBS::Definition::Method::TypeDef#annotations is deprecated with this. It now has #member_annotations for annotations on the method definition and #overload_annotations for annotations on the overload.

Improved validation

PRs: #2237, #2241, #2289, #2294, #2300

RBS 3.9 introduces some validations.

class Foo < Array           # Rejects incorrect type application
  @foo: String
  @foo: Integer             # Rejects the duplicated instance variable declaration

  @bar: String[Integer]     # Rejects variable type validation
end

Note that instance variable declaration duplication validation works for variable declarations but skips instance variables defined through attr_reader-likes.

Untyped proc type can have self type hint

PR: #2325

Untyped proc types, ^(?) -> T, can have self type hint.

type t = ^(?) [self: String] -> void

Replace %a{steep:deprecated} with %a{deprecated}

PR: #2328

RBS now ships with %a{deprecated} annotation. The annotation is supported with Steep >= 1.10.

%a{deprecated}
VERSION: String

%a{deprecated: Use `RBS::VERSION` instead}
VERSION: String

The %a{deprecated} annotation can have optional message after : which is printed on diagnostics to help migration.