[Bug c++/87697] Casting a base class to derived gives no warning

[jynelson at email dot sc.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87697

--- Comment #3 from jynelson at email dot sc.edu ---
Created attachment 44884
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44884&action=edit
Casting unrelated types gives an error