[Bug c++/80309] [7 Regression] ICE: canonical types differ for identical types _Args2 and _Args2

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80309

--- Comment #2 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Started with r246653.