有关shouldRedirectRLocked方法的困惑（go1.11 src / net / http / server.go：2259）

I'm reading the source code about http module, and following code confused me:

func (mux *ServeMux) shouldRedirectRLocked(host, path string) bool {
    p := []string{path, host + path}

    for _, c := range p {
        if _, exist := mux.m[c]; exist {
            return false
        }
    }

    n := len(path)
    if n == 0 {
        return false
    }
    for _, c := range p {
        if _, exist := mux.m[c+"/"]; exist {
            return path[n-1] != '/' <<- why not return true directly
        }
    }

    return false
}

As the comment above this method: shouldRedirectRLocked reports whether the given path and host should be redirected to path+"/". This should happen if a handler is registered for path+"/" but not path -- see comments at ServeMux.

c+"/" already registered, and c didn't , so I think it should return true directly, but why we have to check path[n - 1] != '/'? Is this a question about the http protocol?