#11243: Use Type Synonyms to Compress Errors -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: feature request | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.10.2 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 simonpj):
I believe that GHC attempts to expand type synonyms as much as possible
On the contrary, GHC tries ''not'' to expand type synonyms unless necessary. So the first thing to do is to look at a small example, and see why it is failing to not-expand them. Can you make a test case that is as small as possible, in which a type synoym is expanded that you'd rather wasn't? (I.e. NOT one that demonstrates (as above) that unnecessary expansion is undesirable; we all believe that already.) It's possible that there's a good reason. Then the next thing is to think whether we could improve GHC's existing techniques for delaying expansion. Finally you could try to re-compress expanded types, though that sounds harder. Definitely a good project! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11243#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler