g++-4.8 compiler error

[Ben Goodrich]

g++-4.8 recently went Stage 3, so I ran test-unit with a snapshot of it, which ICEs on src/stan/mcmc/chains.hpp saying

In file included from src/test/mcmc/chains_test.cpp:1:0:
src/stan/mcmc/chains.hpp: In instantiation of 'double stan::mcmc::chains<RNG>::quantile(std::size_t, std::size_t, double) [with RNG = boost::random::additive_combine_engine<boost::random::linear_congruential_engine<unsigned int, 40014u, 0u, 2147483563u>, boost::random::linear_congruential_engine<unsigned int, 40692u, 0u, 2147483399u> >; std::size_t = long unsigned int]':
src/test/mcmc/chains_test.cpp:619:3:   required from here
src/stan/mcmc/chains.hpp:1196:40: internal compiler error: in lookup_member, at cp/search.c:1175
             acc(tail<left>::cache_size = cs);
                                        ^
Please submit a full bug report,
with preprocessed source if appropriate.

Before we submit a bug report, does anyone have any additional insight? The full log snippet and the preprocessed source are attached.

Ben