gc produces the following error message on the program: ``` package a func n() {(interface{int})} ``` ``` go.go:2: type %!v(PANIC=runtime error: invalid memory address or nil pointer dereference) is not an expression ``` The error message needs to be fixed. go version devel +ef37184 Mon Jul 6 00:07:10 2015 +0000 linux/amd64