diff options
Diffstat (limited to 'compiler/GHC/Tc/Utils/Unify.hs')
| -rw-r--r-- | compiler/GHC/Tc/Utils/Unify.hs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/compiler/GHC/Tc/Utils/Unify.hs b/compiler/GHC/Tc/Utils/Unify.hs index 1eb81d8191..af71c50156 100644 --- a/compiler/GHC/Tc/Utils/Unify.hs +++ b/compiler/GHC/Tc/Utils/Unify.hs @@ -205,7 +205,7 @@ Ugh! -- | Like 'matchExpectedFunTys', but used when you have an "actual" type, -- for example in function application. -- --- INVARIANT: the returned arguemnt types all have a syntactically fixed RuntimeRep +-- INVARIANT: the returned argument types all have a syntactically fixed RuntimeRep -- in the sense of Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete. -- See Note [Return arguments with a fixed RuntimeRep]. matchActualFunTysRho :: ExpectedFunTyOrigin -- ^ See Note [Herald for matchExpectedFunTys] @@ -721,7 +721,7 @@ There is one wrinkle. Suppose we have case e of T1 -> e1 :: (forall a. a->a) -> Int G2 -> e2 -where T1 is not GADT or existential, but G2 is a GADT. Then supppose the +where T1 is not GADT or existential, but G2 is a GADT. Then suppose the T1 alternative fills the hole with (forall a. a->a) -> Int, which is fine. But now the G2 alternative must not *just* unify with that else we'd risk allowing through (e2 :: (forall a. a->a) -> Int). If we'd checked G2 first @@ -2219,7 +2219,7 @@ There are five reasons not to unify: assumptions", section 2.2. We say that alpha[1] is "untouchable" inside this implication. - Bottom line: at amibient level 'l', when looking at a constraint + Bottom line: at ambient level 'l', when looking at a constraint alpha[n] ~ ty, do not unify alpha := ty if there are any given equalities between levels 'n' and 'l'. @@ -2261,7 +2261,7 @@ There are five reasons not to unify: is sensible, but it can lead to very confusing error messages. It's very much like a Wanted rewriting a Wanted. Even worse, unifying a variable essentially turns an equality into a Given, - and so we could not use the tracking mechansim in + and so we could not use the tracking mechanism in Note [Wanteds rewrite Wanteds] in GHC.Tc.Types.Constraint. We thus simply do not unify in this case. |