diff options
| author | Simon Peyton Jones <simonpj@microsoft.com> | 2013-10-24 11:15:04 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2013-10-24 11:15:14 +0100 |
| commit | 2650da2b8b744248c2529d8c5969b78cd97239d3 (patch) | |
| tree | 1d110da719c3c5dd21af771cc8a51b45fda6c897 /compiler/coreSyn | |
| parent | 1990c63ba5f4b701ed360d86dcdfe9c2b7da172b (diff) | |
| download | haskell-2650da2b8b744248c2529d8c5969b78cd97239d3.tar.gz | |
Refactor the topNormaliseNewType story, fixing Trac #8467
A bit of a mess had accumulated, with unclear invariants.
* Remove splitNewTypeRepCo_maybe, in favour of topNormaliseNewType_maybe
(which had the same signature but behaved subtly differently).
* Make topNormaliseNewType_maybe guaranteed to return a non-newtype
if it says (Just ty). This is what was causing the loop in #8467
* Apply similar tidying up to FamInstEnv.topNormaliseType
Diffstat (limited to 'compiler/coreSyn')
| -rw-r--r-- | compiler/coreSyn/CoreArity.lhs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/coreSyn/CoreArity.lhs b/compiler/coreSyn/CoreArity.lhs index 9c0fd179ff..d0fa106295 100644 --- a/compiler/coreSyn/CoreArity.lhs +++ b/compiler/coreSyn/CoreArity.lhs @@ -902,7 +902,7 @@ mkEtaWW orig_n orig_expr in_scope orig_ty -- Avoid free vars of the original expression = go (n-1) subst' res_ty (EtaVar eta_id' : eis) - | Just(ty',co) <- splitNewTypeRepCo_maybe ty + | Just (co, ty') <- topNormaliseNewType_maybe ty = -- Given this: -- newtype T = MkT ([T] -> Int) -- Consider eta-expanding this |