#13983: Type synonym referred to as datatype in error message -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler (Type | Version: 8.0.1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Poor/confusing | Unknown/Multiple error message | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3747 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"6e3c901db7a624d030614113c51be5731d1ac862/ghc" 6e3c901d/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="6e3c901db7a624d030614113c51be5731d1ac862" Fix #13983 by creating a TyConFlavour type, and using it An error message was referring to a type synonym as a datatype. Annoyingly, learning that the TyCon over which the error message is operating is actually a type synonym was previously impossible, since that code only had access to a TcTyCon, which doesn't retain any information about what sort of TyCon it is. To rectify this, I created a new TyConFlavour datatype, intended to capture roughly what sort of TyCon we're dealing with. I then performing the necessary plumbing to ensure all TcTyCons have a TyConFlavour, and propagated this information through to the relevant error message. Test Plan: ./validate Reviewers: goldfire, austin, bgamari, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, thomie GHC Trac Issues: #13983 Differential Revision: https://phabricator.haskell.org/D3747 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13983#comment:2> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler