#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: Type: bug | Status: new Priority: high | Milestone: 7.12.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Other | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by thoughtpolice): Also, just a random tidbit: the (excellent!) test in comment:76 can in fact be solved by simply compiling with `-fno-cse` - the nondeterministic ordering of bindings is the culprit in that case, and CSE chooses `return` or `pure` based on what shirt you're wearing. If determinism here is hurting NixOS, it may be preferrable to simply switch off CSE by default or always default to `-fno-cse` for every compilation. That sucks, but in the mean time it may help while we work towards a real fix (having a deterministic ordering for Uniques). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/4012#comment:95 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler