How to ensure valid RBS for include Enumerable?

[thomthom]

Given a class that implement Enumerable:

class Something

  include Enumerable

  # @yield [key, value]
  # @yieldparam [Integer] key
  # @yieldparam [String] value
  # @return void
  def each
    yield 123
  end

end

The generated output is:

class Something
  include Enumerable

  # _@return_ — void
  def each: () ?{ (Integer key, String value) -> void } -> untyped
end

If I then run steep check on this I get errors:

# Type checking files:

............................................F..............F.......

src/enum.rb:1:0: [error] UnexpectedError: sig/example.rbs:1:0...6:3: ::Enumerable expects parameters [Elem], but given args []
│ Diagnostic ID: Ruby::UnexpectedError
│
└ class Something
  ~~~~~~~~~~~~~~~

sig/example.rbs:1:0: [error] Type `::Enumerable` is generic but used as a non generic type
│ Diagnostic ID: RBS::InvalidTypeApplication
│
└ class Something
  ~~~~~~~~~~~~~~~

Detected 2 problems from 2 files

If I alter the RBS to include a param for the Enumerable:

class Something
  include Enumerable[untyped]

  # _@return_ — void
  def each: () ?{ (Integer key, String value) -> void } -> untyped
end

Then it passes:

C:\Users\Thomas\SourceTree\sord-test>steep check
# Type checking files:

...................................................................

No type error detected. 🍵

I'm not actually 100% sure what param to give Enumerable in the case of each yielding key and value params. hence the untyped in this case. But given that you have a collection object that return String objects, then I presume it should be include Enumerable[String]. (?)
Is there a way I can make sord generate an RBS that will not cause an error in steep?

[AaronC81]

Not currently, sorry... I'm not sure how exactly this could be encoded either, since I'm not aware of any way to specify this in YARD. Looking up the type of #each feels possible but a bit hacky and fragile! Do you have any suggestions?

[tk0miya]

I also met a similar case with Struct.

Input:

require 'struct'

Foo = Struct.new(:bar)

Generated:

class Foo < Struct
  # Returns the value of attribute bar
  attr_accessor bar: Object
end

Result of rbs validate command:

/Users/tkomiya/.dotfiles/_rbenv/versions/3.2.2/lib/ruby/gems/3.2.0/gems/rbs-3.1.1/lib/rbs/errors.rb:90:in `check!': sig/sord.rbs:1:0...4:3: ::Struct expects parameters [Elem], but given args [] (RBS::InvalidTypeApplicationError)

It would be nice if we can give a hint to the sord via comments or annotations.