unless defined?(T)
  module T
    def self.any(type_a, type_b, *types); end
    def self.nilable(type); end
    def self.untyped; end
    def self.noreturn; end
    def self.all(type_a, type_b, *types); end
    def self.enum(values); end
    def self.proc; end
    def self.self_type; end
    def self.class_of(klass); end
    def self.type_alias(type); end
    def self.type_parameter(name); end

    def self.cast(value, type, checked: true); value; end
    def self.let(value, type, checked: true); value; end
    def self.assert_type!(value, type, checked: true); value; end
    def self.unsafe(value); value; end
    def self.must(arg, msg=nil); arg; end
    def self.reveal_type(value); value; end
  end

  module T::Sig
    def sig(&blk); end
  end

  module T::Array
    def self.[](type); end
  end

  module T::Hash
    def self.[](keys, values); end
  end

  module T::Enumerable
    def self.[](type); end
  end

  module T::Range
    def self.[](type); end
  end

  module T::Set
    def self.[](type); end
  end

  module T::Boolean
  end
end