1.. title:: clang-tidy - bugprone-non-zero-enum-to-bool-conversion
2
3bugprone-non-zero-enum-to-bool-conversion
4=========================================
5
6Detect implicit and explicit casts of ``enum`` type into ``bool`` where ``enum``
7type doesn't have a zero-value enumerator. If the ``enum`` is used only to hold
8values equal to its enumerators, then conversion to ``bool`` will always result
9in ``true`` value. This can lead to unnecessary code that reduces readability
10and maintainability and can result in bugs.
11
12May produce false positives if the ``enum`` is used to store other values
13(used as a bit-mask or zero-initialized on purpose). To deal with them,
14``// NOLINT`` or casting first to the underlying type before casting to ``bool``
15can be used.
16
17It is important to note that this check will not generate warnings if the
18definition of the enumeration type is not available.
19Additionally, C++11 enumeration classes are supported by this check.
20
21Overall, this check serves to improve code quality and readability by identifying
22and flagging instances where implicit or explicit casts from enumeration types to
23boolean could cause potential issues.
24
25Example
26-------
27
28.. code-block:: c++
29
30  enum EStatus {
31    OK = 1,
32    NOT_OK,
33    UNKNOWN
34  };
35
36  void process(EStatus status) {
37    if (!status) {
38      // this true-branch won't be executed
39      return;
40    }
41    // proceed with "valid data"
42  }
43
44Options
45-------
46
47.. option:: EnumIgnoreList
48
49  Option is used to ignore certain enum types when checking for
50  implicit/explicit casts to bool. It accepts a semicolon-separated list of
51  (fully qualified) enum type names or regular expressions that match the enum
52  type names.
53  The default value is an empty string, which means no enums will be ignored.
54