Initialiser lists don't work for member references in gcc 4.8, see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50025
(This issue is apparently fixed in gcc 4.9, but at least my distro
still ships 4.8 by default.)
This syntax was originally introduced in:
ba7128b30850594c7efb258d1794e377eede364a