False negative -Wunused-result with libc++

[chrchr-github]

#include <vector>

void f(const std::vector<int>& v) {
    v.end() + 1;
}

https://godbolt.org/z/zdvexjY5j
There is no warning with -stdlib=libc++.

With -stdlib=libstdc++:

<source>:4:5: warning: ignoring return value of function declared with 'nodiscard' attribute [-Wunused-result]
    4 |     v.end() + 1;
      |     ^~~~~~~~~~~
1 warning generated.

[frederick-vs-ja]

Looks like that we should put [[__nodiscard__]] on some operators for __wrap_iter (and __bound_iter/__static_bounded_iter).

[philnik777]

I'm not sure that's the right approach. Would it maybe make sense for Clang to warn on overloaded operators generally instead? It already does for overloaded comparison operators.