diff options
Diffstat (limited to 'compiler/rename/RnSource.hs')
| -rw-r--r-- | compiler/rename/RnSource.hs | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/compiler/rename/RnSource.hs b/compiler/rename/RnSource.hs index 0699f80858..5155f3ab84 100644 --- a/compiler/rename/RnSource.hs +++ b/compiler/rename/RnSource.hs @@ -727,15 +727,11 @@ rnFamInstEqn doc mb_cls rhs_kvars ; let pat_kity_vars_with_dups = extractHsTyArgRdrKiTyVarsDup pats -- Use the "...Dups" form because it's needed -- below to report unsed binder on the LHS - ; let pat_kity_vars = rmDupsInRdrTyVars pat_kity_vars_with_dups - - -- all pat vars not explicitly bound (see extractHsTvBndrs) - ; let mb_imp_kity_vars = extractHsTvBndrs <$> mb_bndrs <*> pure pat_kity_vars - imp_vars = case mb_imp_kity_vars of - -- kind vars are the only ones free if we have an explicit forall - Just nbnd_kity_vars -> freeKiTyVarsKindVars nbnd_kity_vars - -- all pattern vars are free otherwise - Nothing -> freeKiTyVarsAllVars pat_kity_vars + + -- Implicitly bound variables, empty if we have an explicit 'forall' according + -- to the "forall-or-nothing" rule. + ; let imp_vars | isNothing mb_bndrs = nubL pat_kity_vars_with_dups + | otherwise = [] ; imp_var_names <- mapM (newTyVarNameRn mb_cls) imp_vars ; let bndrs = fromMaybe [] mb_bndrs @@ -766,7 +762,7 @@ rnFamInstEqn doc mb_cls rhs_kvars -- See Note [Unused type variables in family instances] ; let groups :: [NonEmpty (Located RdrName)] groups = equivClasses cmpLocated $ - freeKiTyVarsAllVars pat_kity_vars_with_dups + pat_kity_vars_with_dups ; nms_dups <- mapM (lookupOccRn . unLoc) $ [ tv | (tv :| (_:_)) <- groups ] -- Add to the used variables |