There are a few Karma failures using the latest Clang due to the pass_container detail class forming mutable references:

http://www.boost.org/development/tests/release/developer/output/dgregor2- boost-bin-v2-libs-spirit-test-karma_repeat1-p2-test-clang-darwin-3-0- debug-karma.html

I know that at least some compilers (e.g., GCC) don't diagnose mutable references, but this code is ill-formed account to the standard. Someone want to take a shot at eliminating or factoring out the mutability to avoid these mutable references?

I'm aware of that and it's on my list of things todo. Thanks Doug for reminding me! Regards Hartmut --------------- http://boost-spirit.com