https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68996
Marek Polacek <mpolacek at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2019-06-14 CC| |mpolacek at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Confirmed, I supposed. There's CWG 743: auto vec = get_vec(); decltype(vec)::value_type v = vec.first(); but that includes decltype in a decl-specifier, which is fine. So struct S { using T = int; } s; decltype(s)::T a; should work but not the testcase in Description.