the only thing we do know is that gcc-7.2 and lower won't handle it at all)...
My main development environment is MSVC on Windows as it's the lowest common denominator usually. Then it's GCC on Linux. Finally, only occasionally, I give it a whirl on clang on FreeBSD. Outcome may cause GCC to sometimes ICE in its unit tests, but really I assure you that GCC is a fine compiler to write Outcome based code with. You very rarely encounter problems in normal coding, and GCC has a Concepts implementation which Outcome uses and makes for much more useful compiler error messages, plus I suspect it's a bit faster to compile as Concepts are easier than SFINAE to evaluate. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/