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  • #9739

Closed
Open
Opened Oct 29, 2014 by bitonic@trac-bitonic

GHC 7.8 chokes on recursive classes

Type checking this makes GHC 7.8.3 loop:

{-# LANGUAGE MultiParamTypeClasses #-}
module Foo where

class Class3 a => Class1 a where

class Class2 t a where
  class2 :: (Class3 t) => a -> m

class (Class1 t, Class2 t t) => Class3 t where

Does not happen in 7.6.3.

I think it's something to do with the Class3 constraint appearing in class2.

Trac metadata
Trac field Value
Version 7.8.3
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
Assignee
Assign to
7.10.1
Milestone
7.10.1 (Past due)
Assign milestone
Time tracking
None
Due date
None
Reference: ghc/ghc#9739