# Extra Clang Tools 21.1.8 documentation

## clang-tidy - bugprone-non-zero-enum-to-bool-conversion

# bugprone-non-zero-enum-to-bool-conversion

Detect implicit and explicit casts of `enum` type into `bool` where `enum` type doesn’t have a zero-value enumerator. If the `enum` is used only to hold values equal to its enumerators, then conversion to `bool` will always result in `true` value. This can lead to unnecessary code that reduces readability and maintainability and can result in bugs.

May produce false positives if the `enum` is used to store other values (used as a bit-mask or zero-initialized on purpose). To deal with them, `// NOLINT` or casting first to the underlying type before casting to `bool` can be used.

It is important to note that this check will not generate warnings if the definition of the enumeration type is not available. Additionally, C++11 enumeration classes are supported by this check.

Overall, this check serves to improve code quality and readability by identifying and flagging instances where implicit or explicit casts from enumeration types to boolean could cause potential issues.

## Example

    enum EStatus {
      OK = 1,
      NOT_OK,
      UNKNOWN
    };

    void process(EStatus status) {
      if (!status) {
        // this true-branch won't be executed
        return;
      }
      // proceed with "valid data"
    }

## Options

EnumIgnoreList

  Option is used to ignore certain enum types when checking for implicit/explicit casts to bool. It accepts a semicolon-separated list of (fully qualified) enum type names or regular expressions that match the enum type names. The default value is an empty string, which means no enums will be ignored.