typename(...) misconstrued as normal 'typename' keyword when used in base list

[drec357]

Low priority problem with the typename(...) syntax:

struct A {};
struct B : A {};

//struct BCopy1 : typename(get<0>($B.bases()).type()) {};
//// ^ "error: 'typename' is redundant; base classes are implicitly types"

using B_base0 = typename(get<0>($B.bases()).type());
struct BCopy2 : B_base0 {};  //Works

The fix I suppose is that wherever Clang is throwing the "typename is redundant" error after a parse, it should now parse just beyond the typename to see if a left parens follows, and only throw the error if it doesn't.