Panic: Template variable unbound in rewrite rule
Installing singletons-1.0
with GHC 7.8.2 on both OS X 10.9.2 and Ubuntu 2014.04 fails:
ghc: panic! (the 'impossible' happened)
(GHC version 7.8.2 for x86_64-apple-darwin):
Template variable unbound in rewrite rule
This seems to be an issue with the optimizer, as the bug only appears with optimization level 2, using the following line in ~/.cabal/config
:
optimization: 2
See also goldfirere/singletons#83
Edited by Miëtek Bak