diff options
Diffstat (limited to 'compiler/GHC/Tc/Gen/Rule.hs')
| -rw-r--r-- | compiler/GHC/Tc/Gen/Rule.hs | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/compiler/GHC/Tc/Gen/Rule.hs b/compiler/GHC/Tc/Gen/Rule.hs index 73dedfbaf5..46b1e16313 100644 --- a/compiler/GHC/Tc/Gen/Rule.hs +++ b/compiler/GHC/Tc/Gen/Rule.hs @@ -477,12 +477,17 @@ getRuleQuantCts wc new_skol_tvs = skol_tvs `extendVarSetList` ic_skols imp rule_quant_ct :: TcTyCoVarSet -> Ct -> Bool - rule_quant_ct skol_tvs ct - | EqPred _ t1 t2 <- classifyPredType (ctPred ct) - , not (ok_eq t1 t2) - = False -- Note [RULE quantification over equalities] - | otherwise - = tyCoVarsOfCt ct `disjointVarSet` skol_tvs + rule_quant_ct skol_tvs ct = case classifyPredType (ctPred ct) of + EqPred _ t1 t2 + | not (ok_eq t1 t2) + -> False -- Note [RULE quantification over equalities] + SpecialPred {} + -- RULES must never quantify over special predicates, as that + -- would leak internal GHC implementation details to the user. + -- + -- Tests (for Concrete# predicates): RepPolyRule{1,2,3}. + -> False + _ -> tyCoVarsOfCt ct `disjointVarSet` skol_tvs ok_eq t1 t2 | t1 `tcEqType` t2 = False |