summaryrefslogtreecommitdiff
path: root/testsuite/tests/typecheck/should_compile/T9971.hs
blob: e02b21e3982ca7675d4ef14fda356c571db48537 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
{-# LANGUAGE FunctionalDependencies #-}
module T9971 where

type Vertex v = v Double

class C a b | b->a  where
  op :: a -> b

foo :: Vertex x
foo = error "urk"

bar x = [op foo, op foo]
 -- This gives rise to a [D] Vertex a1 ~ Vertex a2
 -- And that made the canonicaliser go into a loop (Trac #9971)