Basics
This check is disabled by default.
Learn how to enable it via .credo.exs.
This check has a base priority of normal and works with any version of Elixir.
Explanation
Use and/or/not instead of &&/||/! when operands are booleans.
The strict boolean operators make intent clear and catch accidental truthy
values (e.g. :undefined from Erlang APIs). This check flags &&, ||,
and ! when both operands are clearly boolean-returning — i.e. an
is_* guard call, a comparison operator, a literal boolean, or another
strict boolean operator.
Requiring both sides prevents false positives: and/or raise an
ArgumentError if the left operand is not a boolean at runtime, so
user && is_nil(user.name) must not be rewritten as
user and is_nil(user.name) — user can be nil.
# BAD — both operands are clearly boolean-returning
is_binary(x) && is_integer(y)
is_nil(x) || is_atom(x)
!is_nil(value)
# GOOD
is_binary(x) and is_integer(y)
is_nil(x) or is_atom(x)
not is_nil(value)
# NOT flagged — left side is not boolean-typed; &&/|| is the right tool
user && user.name
user && is_nil(user.name)
config[:timeout] || 5_000Check-Specific Parameters
Use the following parameters to configure this check:
:exclude_test_files
When true, skips test files. Default: false.
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.