var_string=append(s,Foo{""})// ERROR "cannot use .. \(.*untyped string.*\) as .*int.*|incompatible type" "cannot use Foo{.*} \(.*type Foo\) as type int in .*append" "cannot use append\(s\, Foo{.*}\) \(.*type \[\]int\) as type string in (assignment|variable declaration)"