https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90960
--- Comment #2 from Alisdair Meredith <alisdairm at me dot com> --- I agree the second problem looks like a dupe. It has since been pointed out to me that the first error is indeed correct, and simply the error message is less than helpful: [temp.spec]p8 of C++17 says: "If a function declaration acquired its function type through a dependent type (17.6.2.1) without using the syntactic form of a function declarator, the program is ill-formed." I believe this constraint is new to C++17, but so are exception specifications in the type system that I rely on, so this bug report could be safely closed, or treated simply as a feature request for a clearer diagnostic message that members of dependent type can never be function declarations.
