[Bug tree-optimization/93971] std::string considered to alias declared objects of incompatible types

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93971

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Martin Sebor from comment #6)

> I've been thinking of one of two kinds of annotation that wouldn't require
> programs to change and would be sufficient if applied only to the definition
> of the containers: (1) one that would make "std::string::ptr" on par with
> that of any other pointer other than char (i.e., a char that's not allowed
> to be used to access anything but a char object)

but then 

  std::string s;
  char *p = s.c_str();
  *p = '0';
  s[0]

breaks?  ISTR there's ways to get a char * to the std::string storage.