[Bug c++/108335] New: New-expression doesn't perform mandatory copy elision when copy constructor is disabled with `requires`, in a template

[iamsupermouse at mail dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108335

            Bug ID: 108335
           Summary: New-expression doesn't perform mandatory copy elision
                    when copy constructor is disabled with `requires`, in
                    a template
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: iamsupermouse at mail dot ru
  Target Milestone: ---

This doesn't compile, but it should:

    template <typename T>
    struct A
    {
        A(int) {}
        A(const A &) requires false {}; // The condititon can depend on `T`, it
doesn't matter.
    };

    template <typename>
    void foo()
    {
        new A<int>(A<int>(1));
    }

    int main()
    {
        foo<int>();
    }

GCC says it doesn't have a suitable constructor to perform the copy.

This starts working if I make `foo()` a non-template, or =delete `A(const A
&)`, or create the object without `new`.