#10218: GHC creates incorrect code which throws <<loop>> -------------------------------------+------------------------------------- Reporter: yongqli | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: yes Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by AlexET): I have managed to reproduce on windows 64-bit on GHC-7.10.1. I have shrunk the example down. It requires linear, vector and transformers. It needs to be complied with -O1 and -feager-blackholes. The redundant constraint in the context of the type of guessStates is required for the bug to trigger. Inlining calc_zs also prevents the bug from triggering. Adding sharing between xs and ys in guessStates also prevents the bug. Changing the monad to the Identity monad prevents the bug. Removing the VectorSpace space class and just adding the constraints to LinAlg also prevents the bug. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10218#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler