module T::Private::Methods::SignatureValidation

def self.validate_override_mode(signature, super_signature)
  case signature.mode
  when *Modes::OVERRIDE_MODES
    if !Modes::OVERRIDABLE_MODES.include?(super_signature.mode)
      raise "You declared `#{signature.method_name}` as #{pretty_mode(signature)}, but the method it overrides is not declared as `overridable`.\n" \
            "  Parent definition: #{method_loc_str(super_signature.method)}\n" \
            "  Child definition:  #{method_loc_str(signature.method)}\n"
    end
  when *Modes::IMPLEMENT_MODES
    if super_signature.mode != Modes.abstract
      raise "You declared `#{signature.method_name}` as #{pretty_mode(signature)}, but the method it overrides is not declared as abstract.\n" \
            "  Either mark #{super_signature.method_name} as `abstract.` in the parent: #{method_loc_str(super_signature.method)}\n" \
            "  ... or mark #{signature.method_name} as `override.` in the child: #{method_loc_str(signature.method)}\n"
    end
  when *Modes::NON_OVERRIDE_MODES
    if super_signature.mode == Modes.standard
      # Peaceful
    elsif super_signature.mode == Modes.abstract
      raise "You must use `.implementation` when overriding the abstract method `#{signature.method_name}`.\n" \
            "  Abstract definition: #{method_loc_str(super_signature.method)}\n" \
            "  Implementation definition: #{method_loc_str(signature.method)}\n"
    elsif super_signature.mode != Modes.untyped
      raise "You must use `.override` when overriding the existing method `#{signature.method_name}`.\n" \
            "  Parent definition: #{method_loc_str(super_signature.method)}\n" \
            "  Child definition:  #{method_loc_str(signature.method)}\n"
    end
  else
    raise "Unexpected mode: #{signature.mode}. Please report to #dev-productivity."
  end
end