#12945: Backpack signature matching doesn't pick up orphan instances -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.1 checker) | Resolution: | Keywords: backpack 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 Edward Z. Yang <ezyang@…>): In [changeset:"62332f36b62431ddb9ab3c97365288c7d3fc2d39/ghc" 62332f3/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="62332f36b62431ddb9ab3c97365288c7d3fc2d39" Setup tcg_imports earlier during signature matching, so orphans are visible. Summary: Previously, we updated tcg_imports after doing all of the actual matching, which was fine for outputting the interface, but not good enough for checking if all type classes were implemented; we weren't treating orphans as visible (when they needed to be.) Fixes #12945. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: simonpj, austin, bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2802 GHC Trac Issues: #12945 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12945#comment:1> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler