1.. title:: clang-tidy - bugprone-switch-missing-default-case 2 3bugprone-switch-missing-default-case 4==================================== 5 6Ensures that switch statements without default cases are flagged, focuses only 7on covering cases with non-enums where the compiler may not issue warnings. 8 9Switch statements without a default case can lead to unexpected 10behavior and incomplete handling of all possible cases. When a switch statement 11lacks a default case, if a value is encountered that does not match any of the 12specified cases, the program will continue execution without any defined 13behavior or handling. 14 15This check helps identify switch statements that are missing a default case, 16allowing developers to ensure that all possible cases are handled properly. 17Adding a default case allows for graceful handling of unexpected or unmatched 18values, reducing the risk of program errors and unexpected behavior. 19 20Example: 21 22.. code-block:: c++ 23 24 // Example 1: 25 // warning: switching on non-enum value without default case may not cover all cases 26 switch (i) { 27 case 0: 28 break; 29 } 30 31 // Example 2: 32 enum E { eE1 }; 33 E e = eE1; 34 switch (e) { // no-warning 35 case eE1: 36 break; 37 } 38 39 // Example 3: 40 int i = 0; 41 switch (i) { // no-warning 42 case 0: 43 break; 44 default: 45 break; 46 } 47 48.. note:: 49 Enum types are already covered by compiler warnings (comes under -Wswitch) 50 when a switch statement does not handle all enum values. This check focuses 51 on non-enum types where the compiler warnings may not be present. 52 53.. seealso:: 54 The `CppCoreGuideline ES.79 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Res-default>`_ 55 provide guidelines on switch statements, including the recommendation to 56 always provide a default case. 57