#9183: GHC shouldn't expand constraint synonyms -------------------------------------+------------------------------------ Reporter: Feuerbach | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by simonpj): I really don't see what we can reasonably do here. e.g. {{{ type Foo a = (Eq a, Ix a) }}} Now if you instantiate and re-generalise it's really not possible to reconstruct the `Foo a`. I suppose you could have a magical special case when there is a type synonym for a single constraint. That might, just, be possible. But it'd be a bit of effort to push it through, so I propose to wait until more people yell. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9183#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler