https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90196
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Максим Прохоренко from comment #3) > Allocate GiB of unused memory and don't warn about it? But 1 simple double - > it is a big problem. Nobody said that. But the warning has to be driven by simple rules. An unused double is easy to detect and warn about. Knowing if a complex type exists for some reason that the compiler can't infer is harder to do. > For std:: objects with side effect - OK! > But for simple unused vector or set or map??? Destroying elements and deallocating memory is a side effect. The compiler doesn't do arbitrarily complex analysis of what a destructor does, it just considers a non-trivial destructor to be doing something.
