internal error: evacuate(static): strange closure type 42
I have a concurrent program (using CHP, which sits on top of STM+forkIO), that is able to produce this error on GHC 6.12.1-rc1 (which doesn't appear on your version drop-down):
chp-boids: internal error: evacuate(static): strange closure type 42
(GHC version 184.108.40.20691010 for i386_unknown_linux)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
It produces it much sooner with +RTS -N2 than +RTS -N1, but both settings can produce the error. The output doesn't look like it will be very useful to you -- what can I run to give a better output?