https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72792
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Liviu Ionescu from comment #6) > > If you have real world code that is affected ... > > I do, it is called µOS++, and it is a C++ RTOS with advanced memory > management features, using C++17 memory resources and C++11 standard > allocators: > > https://github.com/micro-os-plus/micro-os-plus-iii > > It was developed on clang and GCC 5.x. When I tried GCC 6.x, it failed. > Today I took some time to understand why, and discovered the static assert > in the allocator_traits<> template. > > I removed it and this solved the problem. > > Now I'm working on a patch for GCC 6.x distributions, so I can run my tests > on CI servers until 6.4 will be released. > > I'm a bit surprised that there were no other reports, according to my tests > the bug affected all custom allocators that use pointers to functions or > pointer to class members as template parameters. (I wrote a simple test, > trying several types of template parameters). Only if they don't provide their own "rebind" If the allocator provides a rebind then it will be used, and there's no need for the deduction (which fails with non-type template parameters). The simplest fix would be to add rebind to your allocators: template<class T, void*(*F)(int)> struct Alloc { using value_type = T; template<typename U> struct rebind { using other = Alloc<U, F>; }; // ... }; This will work with any C++11 compiler.
