Report IPE information of thunks involved in cycles
Currently debugging cyclic thunks (e.g. the NonTermination
exception, which manifests as the dreaded <<loop>>
message) is quite difficult. I generally have to resort to ghc-debug
or gdb
to understand such cases. However, with IPE information we now have the ability to determine the provenance of thunks. It would be nice if GHC could attach the set of IPE information (and perhaps cost-centers, if profiling) involved in the cycle to the NonTermination
exception.