[Bug go/83071] gccgo: ICE in set_type

[ian at airs dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83071

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> ---
This is of course a compiler bug, but it's a crash on invalid code.  You can't
write `input++` when `input` is a string type.  In Go the `++` operator only
applies to integer types.  When I fix the compiler bug, you will get an error
compiling this code instead of a crash.