[Bug c++/90789] gcc complains cannot capture 'f()()' by reference on valid code

[zhonghao at pku dot org.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90789

zhonghao at pku dot org.cn changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|gcc                         |gcc complains cannot
                   |                            |capture 'f()()' by
                   |                            |reference on valid code

--- Comment #1 from zhonghao at pku dot org.cn ---
My gcc is 10.0.0, and the code is:

#include <iostream>
struct S { ~S() { std::cout << "dtor\n"; } };
const S f() { return {}; }
int main() {
 [&x(f())]{ std::cout << "in lambda\n"; }();
 std::cout << "end of main\n";
}

The error message is:
<source>: In function 'int main()':

<source>:5:9: error: cannot capture 'f()()' by reference

    5 |  [&x(f())]{ std::cout << "in lambda\n"; }();

      |         ^

Compiler returned: 1

I tried clang, icc, and msvc. They all accept the code.