[Bug c++/51829] decltype() deduces non-const but only in a template

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51829

--- Comment #2 from Seth Heeren <bugs at sehe dot nl> 2012-01-12 00:30:36 UTC 
---
To clarify, the valid code that was rejected looks like:

     auto expr = boost::spirit::qi::eps(false) | '1';

this might explain the 'strange' breaking up into e1 and e2 for the minimal
testcase. 

HTH