#15147: Type checker plugin receives Wanteds that are not completely unflattened -------------------------------------+------------------------------------- Reporter: nfrisby | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler (Type | Version: 8.4.1 checker) | Keywords: type checker Resolution: | plugins 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 adamgundry): I'm also seeing this trying to port `uom-plugin` to 8.4. Unfortunately I've got the details of how this works in GHC pretty well paged out, and I think the code may have evolved a bit since I worked on it. The original thinking was to avoid bothering typechecker plugins with the complications of flattening and zonking, on the basis that sets (well, lists) of constraints are a simpler model to work with. But perhaps in practice the plugin interface is so low level that we would be better off doing as little as possible before handing constraints over to the plugin. Assuming we can make it relatively easy for the plugin to flatten/zonk if it wants to, that is... -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15147#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler