[Bug c++/59838] ICE with an enum using an incomplete type

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59838

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
With the patch cc1plus says:

ee.C:1:32: error: conversion to incomplete type
 enum E { a, b = true ? 1 : ((E)a, 0) };
                                ^
ee.C:1:33: error: a comma operator cannot appear in a constant-expression
 enum E { a, b = true ? 1 : ((E)a, 0) };
                                 ^