[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 #1 from James Michael DuPont <JamesMikeDuPont at googlemail dot 
com> ---
output is :

test.go:6:8: error: expected type