Templated code can lead to some really long symbol names. As a random tangent, I was trying to figure out why Chrome's stack symbolizer wasn't working for some stack frames this week… and came across this comment in the symbolizer.

  char demangled[256];  // Big enough for sane demangled symbols.

Turns out the longest symbol name in the Chrome binary is 32k characters long... and some of the tests have even longer ones (the longest one I found was 98k characters).