cppcheck 1.71 false union member not used

[Wilson Snyder]

The following small test case extracted from a larger program with cppcheck 1.71 (but not 1.52) gives

$ cppcheck --enable=all below.cpp

[...:4]: (style) union member 'Anonymous0::r' is never used.

It is being set, and read through the other member. I can appreciate some use of unions is for two disjoint but non-simultanious data sets in which case not using one would be an error, but perhaps if you see a union with two members, one being written and the other read, you could auto suppress it?

#include <stdint.h>
extern uint64_t r_to_u(double r);
uint64_t r_to_u(double r) {
    union { double r; uint64_t ld; } u;
    u.r = r;
    return u.ld;
}

[Alexander Mai]

If you can reproduce it with the latest version still (1.72) you should report it on http://trac.cppcheck.net !