Changes between Version 2 and Version 3 of TFvsFD
 Timestamp:
 Jun 5, 2012 7:20:31 PM (4 years ago)
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TFvsFD
v2 v3 82 82 }}} 83 83 84 Type synonyms can manipulate constraint kinds but can not use 85 them. The standard encoding of the above class from FD to 86 superclass equalities does not work. 84 The standard encoding of the above class from FD to 85 superclass equalities does not work because type instances 86 can't have type variables on the RHS which weren't introduced 87 in the LHS: 87 88 88 89 {{{ 89 90 class (f :<$>: a) ~ b => FMap (f :: * > * > Constraint) a b 90 91 where type f :<$>: a 91 instance f a b => FMap f (HJust a) b92 where type f :<$>: (HJust a) = HJust b 92 instance f a b => FMap f (HJust a) (HJust b) 93 where type f :<$>: (HJust a) = HJust b  error, b not available 93 94 }}} 94 95