On 2017.07.20 at 09:33 -0400, Andrew Sutton wrote: > This adds a new C++ dialect, enabled by -std=c++2a. > > libcpp/ > Add support for C++2a. > * include/cpplib.h (c_lang): Add CXX2A and GNUCXX2A. > * init.c (lang_defaults): Add rows for CXX2A and GNUCXX2A. > (cpp_init_builtins): Set __cplusplus to 201707L for C++2x. > > gcc/c-family/ > Add support for -std=c++2a. > * c-common.h (cxx_dialect): Add cxx2a as a dialect. > * opt.c: Add options for -std=c++2a and -std=gnu++2a. > * c-opts.c (set_std_cxx2a): New. > (c_common_handle_option): Set options when -std=c++2a is enabled. > > gcc/testsuite/ > New test for -std=c++2a. > * g++.dg/cpp2a/cplusplus.C: New.
Perhaps you should enable -fconcepts by default? -- Markus
