[project @ 2001-03-01 15:06:52 by simonpj]

[project @ 2001-03-01 15:06:52 by simonpj]
Improve rule matching even more

Manuel discovered that given

  {-# RULES "fst over sndSnd" forall v. fst (sndSnd v) = fst v #-}

  sndSnd :: (a, (b, c)) -> (a, c)
  sndSnd (x, (y, z)) = (x, z)

the rule gets a type, which is too specialised, namely

  {-## __R "fst over sndSnd" __forall {@ a1 v :: (a1, ((), ()))}
	   fst @ a1 @ () (sndSnd @ a1 @ () @ () v) = fst @ a1 @ ((), ()) v ;

This was because TcRules wasn't quantifying over enough type variables.

This commit fixes the problem.
The test is in tests/simplCore/should_run/simplrun002