Re: [GHC] #13618: Reified data family instances type variables not related to value constructor fields

#13618: Reified data family instances type variables not related to value constructor fields -------------------------------------+------------------------------------- Reporter: glguy | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler (Type | Version: 8.2.1-rc1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3505 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"b2c38d6b4003d3dda60d15204283da5aab15c2ec/ghc" b2c38d6/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="b2c38d6b4003d3dda60d15204283da5aab15c2ec" Make the tyvars in TH-reified data family instances uniform It turns out we were using two different sets of type variables when reifying data family instances in Template Haskell. We were using the tyvars quantifying over the instance itself for the LHS, but using the tyvars quantifying over the data family instance constructor for the RHS. This commit uses the instance tyvars for both the LHS and the RHS, fixing #13618. Test Plan: make test TEST=T13618 Reviewers: goldfire, austin, bgamari Reviewed By: goldfire, bgamari Subscribers: rwbarton, thomie GHC Trac Issues: #13618 Differential Revision: https://phabricator.haskell.org/D3505 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13618#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler