The confusion begins the moment you think Go variables get allocated on the stack, in the C sense. They don't, semantically. Stack allocation is an optimization that the Go compiler can sometimes do for you, with no semantics associated with it.

The following Go code also works perfectly well, where it would obviously be UB in C:

  func foo() *int {
    i := 7
    return &i
  }

  func main() {
    x := foo()
    fmt.Printf("The int was: %d", *x) //guaranteed to print 7
  }