#13885: Template Haskell doesn't freshen GADT type variables properly -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.4.1 Component: Template Haskell | Version: 8.0.1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: th/T13885 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3867 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ryan Scott <ryan.gl.scott@…>): In [changeset:"6330b0b0938bc7b27463b3bbfa0df661e4a966b1/ghc" 6330b0b/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="6330b0b0938bc7b27463b3bbfa0df661e4a966b1" Document the intricacies of ForallC variable quantification better Summary: I recently (re-)discovered that `ForallC` quantifies different type variables depending on whether `GadtC` is present or not. This is an important enough gotcha where I feel like this fact should also be advertised in the `template-haskell` documentation itself, so this patch does just that. Test Plan: Read it Reviewers: goldfire, austin, bgamari Subscribers: rwbarton, thomie GHC Trac Issues: #13885 Differential Revision: https://phabricator.haskell.org/D3880 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13885#comment:10> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler