#10371: GHC fails to inline and specialize a function -------------------------------------+------------------------------------- Reporter: MikeIzbicki | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: #8668 | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by MikeIzbicki): I figured out a solution that works for me. Inside my class hierarchy there were several definitions that are similar to type synonyms: {{{ class (Rg r, Group r) => Rng r instance (Rg r, Group r) => Rng r }}} instead of: {{{ type Rng r = (Rg r, Group r) }}} Replacing these definitions with actual type synonyms fixed the problem. I was using the original version for two reasons. First, GHC 7.8 lacks ConstraintKinds support in TemplateHaskell. This is obviously not relevant after the upgrade to 7.10. Second, There are places where I would prefer to be able to partially apply the constraint, which you can't do as a type synonym. I can live without partial application, but it would be nice to have back. Unfortunately, these class definitions are not the sole cause of the problem. I tried recreating the relevant subset of my class hierarchy in another file. But I couldn't reproduce the problem using only this subset of code. So these classes must somehow be interacting with another part of the library which (seems to be) unrelated. Tracking down this other cause and giving a nice short test case here seems like more work than I can put into this since I have a workaround. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10371#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler