When formatting function calls that provide variadic arguments using `slice...`, gofmt
drops "...":

% cat sample.go
package main

func doSomething(args ...string) {
}

func main() {
    values := []string{"a", "b"}
    doSomething(values...)
}
% gofmt -r 'doSomething(a) -> DoSomething(a)' sample.go
package main

func doSomething(args ...string) {
}

func main() {
    values := []string{"a", "b"}
    DoSomething(values)
}

It rewrote doSomething(values...) to DoSomething(values), meaning that the code does not
compile anymore.