[clang-tidy] bugprone-unused-return-value false positive will matching assignment

[HerrCai0907]

It seems like this is a bigger issue.

If you use ::.* for CheckedFunctions to match all functions it will report the warning on every assignment (= and +=) regardless of type.

Originally posted by @firewave in #84314 (comment)

Here's an example:

#include <string>

class C {
public:
    void setS(const char* s) {
        mS = s;
    }
private:
    std::string mS;
};

test.cpp:6:9: error: the value returned by this function should not be disregarded; neglecting it may lead to errors [bugprone-unused-return-value,-warnings-as-errors]
    6 |         mSt = s;
      |         ^~~~~~~

(No godbolt link as I could not figure out how to make the passing of the option work)

Originally posted by @firewave in #84314 (comment)