#14609: Per-instance UndecidableInstances -------------------------------------+------------------------------------- Reporter: ryanreich | Owner: (none) Type: feature request | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.2.2 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 AntC): Ooh-er. I've just seen that Type Families also use the `UndecidableInstances` flag. https://downloads.haskell.org/~ghc/8.2.2/docs/html/users_guide/glasgow_exts.... #type-family-decidability The whole idea of making the flag per-instance is that we avoid putting a blanket flag on a whole module. So implementing this ticket needs a per- type-family-instance pragma as well as a per-class-instance(?). Then for Closed Type Families: is that a pragma for the whole family decl, or per- equation? yeuch. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14609#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler