#14778: FunDep origin not correctly attributed -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Keywords: FunDeps | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In `TcInteract.improveTopFunEqs` we do not give the derived constraints an origin of `FunDepOrigin`. As a result, `dropDerivedSimples` will discard even an insoluble constraint arising from a fundep. In contrast class instance fundeps do have `FunDepOrigin` and are kept. This is at least inconsistent. And we get less good error messages. Shows up in tests `T13651, `TR8450`, `T13506`, `T14325`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14778 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler