id summary reporter owner description type status milestone component version severity resolution keywords cc 6311 Broken const-ref semantics Akim Demaille Ion Gaztañaga "in Boost 1.48, unordered_maps seem to have lost the semantics of constrefs that ""enl4rge your object lifetime"". The following runs are on a Mac OS X Lion, native clang++ 2.1 and native G++ 4.2. The latter is completely wrong. It used to be correct. Boost 1.48 installed via MacPorts. {{{ clang++ 2.1 $ /tmp/foo.clang make_map: size: 2, bar => BAR, foo => FOO return_map: size: 2, bar => BAR, foo => FOO main: size: 2, bar => BAR, foo => FOO g++ 4.2 $ /tmp/foo.gcc make_map: size: 2, bar => BAR, foo => FOO return_map: size: 0 main: size: 0 }}} " Bugs closed To Be Determined move Boost 1.48.0 Regression fixed