[Bug c++/82299] -Wuseless-cast errors on typed enums used in member data initializers in c++1z

[matt at godbolt dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82299

--- Comment #5 from Matt Godbolt <matt at godbolt dot org> ---
NB the proposed patch above has a test that compiles with -std=c++11 -- this
bug only occurs with std=c++1z, not 11. The fix may be right, but I wonder if
the test needs to be changed? Unless I've misread something.