diff options
Diffstat (limited to 'compiler/rename/RnTypes.hs')
| -rw-r--r-- | compiler/rename/RnTypes.hs | 21 |
1 files changed, 8 insertions, 13 deletions
diff --git a/compiler/rename/RnTypes.hs b/compiler/rename/RnTypes.hs index abdaaae7e2..f9ce0199c2 100644 --- a/compiler/rename/RnTypes.hs +++ b/compiler/rename/RnTypes.hs @@ -827,7 +827,7 @@ bindHsQTyVars :: forall a b. -> (LHsQTyVars GhcRn -> Bool -> RnM (b, FreeVars)) -- The Bool is True <=> all kind variables used in the -- kind signature are bound on the left. Reason: - -- the TypeInType clause of Note [Complete user-supplied + -- the last clause of Note [CUSKs: Complete user-supplied -- kind signatures] in HsDecls -> RnM (b, FreeVars) @@ -840,7 +840,6 @@ bindHsQTyVars :: forall a b. bindHsQTyVars doc mb_in_doc mb_assoc body_kv_occs hsq_bndrs thing_inside = do { let hs_tv_bndrs = hsQTvExplicit hsq_bndrs bndr_kv_occs = extractHsTyVarBndrsKVs hs_tv_bndrs - ; rdr_env <- getLocalRdrEnv ; let -- See Note [bindHsQTyVars examples] for what -- all these various things are doing @@ -850,8 +849,7 @@ bindHsQTyVars doc mb_in_doc mb_assoc body_kv_occs hsq_bndrs thing_inside -- Make sure to list the binder kvs before the -- body kvs, as mandated by -- Note [Ordering of implicit variables] - implicit_kvs = filter_occs rdr_env bndrs kv_occs - -- Deleting bndrs: See Note [Kind-variable ordering] + implicit_kvs = filter_occs bndrs kv_occs -- dep_bndrs is the subset of bndrs that are dependent -- i.e. appear in bndr/body_kv_occs -- Can't use implicit_kvs because we've deleted bndrs from that! @@ -879,17 +877,15 @@ bindHsQTyVars doc mb_in_doc mb_assoc body_kv_occs hsq_bndrs thing_inside all_bound_on_lhs } } where - filter_occs :: LocalRdrEnv -- In scope - -> [Located RdrName] -- Bound here + filter_occs :: [Located RdrName] -- Bound here -> [Located RdrName] -- Potential implicit binders -> [Located RdrName] -- Final implicit binders -- Filter out any potential implicit binders that are either - -- already in scope, or are explicitly bound here - filter_occs rdr_env bndrs occs + -- already in scope, or are explicitly bound in the same HsQTyVars + filter_occs bndrs occs = filterOut is_in_scope occs where - is_in_scope locc@(L _ occ) = isJust (lookupLocalRdrEnv rdr_env occ) - || locc `elemRdr` bndrs + is_in_scope locc = locc `elemRdr` bndrs {- Note [bindHsQTyVars examples] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1586,9 +1582,8 @@ must come after any variables mentioned in their kinds. typeRep :: Typeable a => TypeRep (a :: k) -- forall k a. ... The k comes first because a depends on k, even though the k appears later than -the a in the code. Thus, GHC does a *stable topological sort* on the variables. -By "stable", we mean that any two variables who do not depend on each other -preserve their existing left-to-right ordering. +the a in the code. Thus, GHC does ScopedSort on the variables. +See Note [ScopedSort] in Type. Implicitly bound variables are collected by any function which returns a FreeKiTyVars, FreeKiTyVarsWithDups, or FreeKiTyVarsNoDups, which notably |