#13099: recompilation can fail to recheck type family instance consistency -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: rwbarton Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by ezyang): I think the problem is that (1) doesn't go far enough: it incorporates into the hash the list of orphan modules that we transitively hash, but NOT the actual LHSes of the type family instances. So #12723 handles if we rename a module, but not if we change an LHS (which can also invalidate a consistency check.) As always with these sorts of bugs, a failing test case helps a lot! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13099#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler