David Deakins wrote:
While using proto with some classes that have a templated operator[] on VC8 and VC9, I have run into a '2 overloads have similar conversions' ambiguity error (C2666). The problem seems to be with subscript_wrapper in detail/decltype.hpp, where neither the templated operator[] from the original class nor the fallback 'any operator[](any)' function in subscript_wrapper have priority. Any thoughts on how to tweak subscript_wrapper so that the 'any operator[](any)' function looks like a worse match than the templated operator[] and thus prevents the ambiguity? I attached a small test case that reproduces the problem. Also, for reference, I am using the proto code from the release branch as of a couple days ago (~12 Jan 2009).
I can reproduce this error with msvc but not with gcc. I think this may be a msvc bug. Sadly, I don't know of a work-around. I'll give the issue some thought. Thanks for the report. -- Eric Niebler BoostPro Computing http://www.boostpro.com