Demand information of foreign calls is wrong
Foreign calls of all types (including prim calls) use
mkFCallId to create a fresh
Id for each one. This Id claims to be strict in all arguments, which is not correct for foreign calls that allow lifted types to be passed. This also causes some trouble for GHCJS.
I hope to get a fix in 7.10.3. Can we leave the strictness sig out entirely perhaps? Most arguments would be trivially strict since they're unboxed.