Minimal example:
#include <utility>
struct A {
A(int x) {}
};
int main() {
int x = 3, y = 3;
//std::pair<A, A> pa(A(3), A(3));
//std::pair<A, A> pa(A(x), A(y));
//std::pair<A, A> pa((A(x)), A(x));
std::pair<A, A> pa(A(x), A(x));
}
Why does this C++ code snippet not compile? I tried various compilers on Godbolt, and the compiler errors/warnings look something like this:
<source>:10:29: error: redefinition of parameter 'x'
std::pair<A, A> pa(A(x), A(x));
^
<source>:10:23: note: previous declaration is here
std::pair<A, A> pa(A(x), A(x));
^
<source>:10:20: warning: parentheses were disambiguated as a function declaration [-Wvexing-parse]
std::pair<A, A> pa(A(x), A(x));
The commented out lines are examples of "fixes" to make it work as expected: I wish to create a new pair of constructed As. I can do it out of constants, but I can't do it out of variables with the same value as the constant! The parser breaks.
It's like it's interpreting that line as:
std::pair<A, A> pa(A x, A x);
, which I don't understand.
Can anyone explain what's going on here?
