View Source Credo.Check.Readability.Specs (Credo v1.7.4)


This check is disabled by default.

Learn how to enable it via .credo.exs.

This check is tagged :controversial

This means that this check is more opinionated than others and not for everyone's taste.

This check has a base priority of 0 and works with any version of Elixir.


Functions, callbacks and macros need typespecs.

Adding typespecs gives tools like Dialyzer more information when performing checks for type errors in function calls and definitions.

@spec add(integer, integer) :: integer
def add(a, b), do: a + b

Functions with multiple arities need to have a spec defined for each arity:

@spec foo(integer) :: boolean
@spec foo(integer, integer) :: boolean
def foo(a), do: a > 0
def foo(a, b), do: a > b

The check only considers whether the specification is present, it doesn't perform any actual type checking.

Like all Readability issues, this one is not a technical concern. But you can improve the odds of others reading and liking your code by making it easier to follow.

Check-Specific Parameters

Use the following parameters to configure this check:


Include private functions.

This parameter defaults to false.

General Parameters

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.