NoMethodError: undefined method `required_positionals'

[aaronmallen]

Hi, I am running into an issue with blocks in rbs. It should be noted that this spec passes with rbs disabled.

rbs 3.5.3

given the following RSpec spec:

describe '.parameter' do
  it 'adds a parameter to the parameter set' do
    described_class.parameter(:test) do
      desc 'A test parameter'
    end

    expect(described_class.parameters.test).to be_an_instance_of(Domainic::Type::Constraint::Parameter)
      .and(have_attributes(name: :test, description: 'A test parameter'))
  end
end

and the following signatures:

class Base
  class << self
    def parameter(parameter_name, &)
      parameter_builder.define(parameter_name, &).build!
    end
    
    private
  
    def parameter_builder
      @parameter_builder ||= DSL::ParameterBuilder.new(self)
    end
  end
end

class Base
 def self.parameter: (::String | Symbol parameter_name) { (?) -> DSL::ParameterBuilder } -> void
 
 private

 def self.parameter_builder: -> DSL::ParameterBuilder
end

module DSL
  class ParameterBuilder
    def define(parameter_name, &)
      @current_parameter = @data[parameter_name.to_sym] ||=
        PARAMETER_DEFAULTS.transform_values(&:dup).merge(name: parameter_name.to_sym)
      instance_exec(&) if block_given?
      self
    end

    def description(description_string)
      raise ArgumentError, 'No parameter is currently being defined' if @current_parameter.nil?

      @current_parameter[:description] = description_string
      self
    end
    alias desc description
  end
end

module DSL
 class ParameterBuilder
   def define: (::String | ::Symbol parameter_name) { (?) -> self } -> self
   def description: (::String description_string) -> self
   alias desc description
 end
end

I get:

NoMethodError: undefined method `required_positionals' for #<RBS::Types::UntypedFunction:0x0000000110c3fe68 @return_type=#<RBS::Types::ClassInstance:0x0000000110c3ff30 @name=#<RBS::TypeName:0x0000000110c12030 @namespace=#<RBS::Namespace:0x0000000110c12080 @path=[:Domainic, :Type, :DSL], @absolute=true, @parent=#<RBS::Namespace:0x0000000110c11fb8 @path=[:Domainic, :Type], @absolute=true, @parent=#<RBS::Namespace:0x0000000110c11ec8 @path=[:Domainic], @absolute=true, @parent=#<RBS::Namespace:0x0000000110c11dd8 @path=[], @absolute=true>>>>, @name=:ParameterBuilder, @kind=:class>, @args=[], @location=#<RBS::Location:11700 buffer=domainic-type/sig/domainic/type/constraint/base/base.rbs, start=15:72, pos=369...390, children=name,?args source="DSL::ParameterBuilder">>>

  0) Domainic::Type::Constraint::Base.parameter adds a parameter to the parameter set
     Failure/Error:
       described_class.parameter(:test) do
         desc 'A test parameter'
       end

     NoMethodError:
       undefined method `required_positionals' for #<RBS::Types::UntypedFunction:0x0000000110c3fe68 @return_type=#<RBS::Types::ClassInstance:0x0000000110c3ff30 @name=#<RBS::TypeName:0x0000000110c12030 @namespace=#<RBS::Namespace:0x0000000110c12080 @path=[:Domainic, :Type, :DSL], @absolute=true, @parent=#<RBS::Namespace:0x0000000110c11fb8 @path=[:Domainic, :Type], @absolute=true, @parent=#<RBS::Namespace:0x0000000110c11ec8 @path=[:Domainic], @absolute=true, @parent=#<RBS::Namespace:0x0000000110c11dd8 @path=[], @absolute=true>>>>, @name=:ParameterBuilder, @kind=:class>, @args=[], @location=#<RBS::Location:11700 buffer=domainic-type/sig/domainic/type/constraint/base/base.rbs, start=15:72, pos=369...390, children=name,?args source="DSL::ParameterBuilder">>>
     # ./domainic-type/spec/domainic/type/constraint/base_spec.rb:11:in `block (3 levels) in <top (required)>'
     # ------------------
     # --- Caused by: ---
     # NoMethodError:
     #   undefined method `desc' for #<RSpec::ExampleGroups::DomainicTypeConstraintBase::Parameter "adds a parameter to the parameter set" (./domainic-type/spec/domainic/type/constraint/base_spec.rb:10)>
     #   ./domainic-type/spec/domainic/type/constraint/base_spec.rb:12:in `block (4 levels) in <top (required)>'

Additionally the recommended annotation to skip tests does not fix the issue:

%a{rbs:test:skip} def self.parameter: (::String | Symbol parameter_name) { (?) -> DSL::ParameterBuilder } -> void

[miharekar]

Related issue on Ruby LSP which seems to be caused because of this: Shopify/ruby-lsp#2630