https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77875
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Doesn't this depend on the resolution of Core 1521 (still "drafting"), dealing with T{expr} where T is a reference type? Which is what this PR is about: void f () { int i = 42; using T = int&; T t = T{i}; }