In my understanding, if constexpr(consdition) should be evaluated at compile time, at least when condition can always be evaluated at compile time.
The same is true for std::enable_if.
However, the following code does not compile:
template <typename A, typename B>
typename std::enable_if_t<!std::is_same_v<A, B>, size_t> do_something(const A arg) {
if constexpr (std::is_same_v<A, B>) {
static_assert(false);
} else {
(void) arg;
return 42;
}
}
It returns
./test.h:25:13: error: static_assert failed
static_assert(false);
In my mind, the error means that either enable_if<A != B> or if constexpr(A == B) are not evaluated at compile time.
Why does this not work?
I am using gcc 11.0.1.
