C and C++


LANG.TYPE.CGEN.IAT : Inappropriate Association Type in C Generic

Summary

A C generic selection expression contains an association that can never be selected because its type name specifies one or more of the following.

The controlling expression undergoes lvalue conversion before type comparison takes place, so its type will never match any of the above

Properties

Class Name Inappropriate Association Type in C Generic
Significance style
Mnemonic LANG.TYPE.CGEN.IAT
Categories
MisraC2023 MisraC2023:23.4 A generic association shall list an appropriate type
Misra2012 Misra2012:23.4 A generic association shall list an appropriate type
Availability Available for C only (not C++).
Enabling Checks for this warning class are disabled by default, and require the unnormalized C ASTs for the project. To enable them, add the following WARNING_FILTER rule and RETAIN_UNNORMALIZED_C_AST specification to the project configuration file.
RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Inappropriate Association Type in C Generic"
Note that retaining the unnormalized ASTs will increase the disk space used to store the project representation, and may make the analysis take longer.

Example

typedef int int32_t;

int lang_type_cgen_iat(int32_t x){
    int rv=0;
    rv += _Generic(x,
                   const int32_t: x, /* 'Inappropriate Association Type in C Generic' warning issued here
                                      * - type is const-qualified, so can never match lvalue-converted controlling expression
                                      */
                   default: 1);
    rv += _Generic(x,
                   int32_t: x,                /* ok: type is not const-qualified or otherwise inappropriate */
                   default: 1);
    return rv;
}

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.