message: also test push_str ptr stability (the original report)
diff: @@ -104,6 +104,14 @@ fn vec_truncate_ptr_stable() {
  let _val = *v0;
  }
  +fn push_str_ptr_stable() {
  + let mut buf = String::with_capacity(11);
  + buf.push_str("hello");
  + let hello: &str = unsafe { &*(buf.as_str() as *const _) }; // laundering the lifetime -- we take care that `buf` does not reallocate, so that's okay.
  + buf.push_str(" world");
  + assert_eq!(format!("{}", hello), "hello");
  +}
  +
  fn main() {
  assert_eq!(vec_reallocate().len(), 5);
  @@ -127,4 +135,5 @@ fn main() {
  vec_push_ptr_stable();
  vec_extend_ptr_stable();
  vec_truncate_ptr_stable();
  + push_str_ptr_stable();
  }
  