[Bug go/65272] switch on type of interface failing

[JamesMikeDuPont at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65272

--- Comment #2 from James Michael DuPont <JamesMikeDuPont at googlemail dot 
com> ---
also on github https://github.com/golang/go/issues/10047