#13102: orphan family instances can leak through the EPS in --make mode -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: rwbarton Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: 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 Ben Gamari <ben@…>): In [changeset:"bedcb71659253bb8ab5d449df8e3ee884cc85d46/ghc" bedcb71/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="bedcb71659253bb8ab5d449df8e3ee884cc85d46" Check local type family instances against all imported ones We previously checked type family instance declarations in a module for consistency with all instances that we happened to have read into the EPS or HPT. It was possible to arrange that an imported type family instance (used by an imported function) was in a module whose interface file was never read during compilation; then we wouldn't check consistency of local instances with this imported instance and as a result type safety was lost. With this patch, we still check consistency of local type family instances with all type family instances that we have loaded; but we make sure to load the interface files of all our imports that define family instances first. More selective consistency checking is left to #13102. On the other hand, we can now safely assume when we import a module that it has been checked for consistency with its imports. So we can save checking in checkFamInstConsistency, and overall we should have less work to do now. This patch also adds a note describing the Plan for ensuring type family consistency. Test Plan: Two new tests added; harbormaster Reviewers: austin, simonpj, bgamari Reviewed By: simonpj, bgamari Subscribers: ggreif, thomie Differential Revision: https://phabricator.haskell.org/D2992 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13102#comment:19> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler