https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90550
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Started with r145440. Before that: 90550.C: In function ‘void f() [with <template-parameter-1-1> = int]’: 90550.C:9: instantiated from here 90550.C:5: error: ‘b’ has incomplete type
