This improves readability and (theoretically) improves portability,
as _Ugly names are reserved.
This performs additional de-uglification, so all of these tests
follow the example of iterator.traits/empty.pass.cpp.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@310761 91177308-0d34-0410-b5e6-96231b3b80d8
Creating a function pointer with proper parameters pointing to std::next() or std::prev() should work.
This change moves the invented paramater for enable_if over to the return type to resolve this QoI issue.
Patch by Jason Liu.
Differential Revision: https://reviews.llvm.org/D34649
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@308932 91177308-0d34-0410-b5e6-96231b3b80d8
