[Bug libstdc++/62039] New: concept checking for std::prev

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62039

            Bug ID: 62039
           Summary: concept checking for std::prev
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: glisse at gcc dot gnu.org

Hello,

std::prev forwards to advance without any concept checking, and advance then
doesn't mind if the iterator is a forward iterator. I have seen several posts
on stackoverflow where people complained that the compiler didn't tell them how
silly their code was, and it would have been nice to be able to say: look, it
does if you ask nicely with -D_GLIBCXX_CONCEPT_CHECKS. Yes, I know those are
deprecated, feel free to close immediatly.