Add a comment about pattern coercions

diff --git a/compiler/typecheck/TcPat.lhs b/compiler/typecheck/TcPat.lhs
index 8c73fa9..5592b80 100644 (file)
--- a/compiler/typecheck/TcPat.lhs
+++ b/compiler/typecheck/TcPat.lhs
@@ -433,7 +433,11 @@ tc_pat pstate (SigPatIn pat sig_ty) pat_ty thing_inside
             failWithTc (badSigPat pat_ty)
        ; (pat', tvs, res) <- tcExtendTyVarEnv2 tv_binds $
                              tc_lpat pat inner_ty pstate thing_inside
-       ; return (SigPatOut pat' inner_ty, tvs, res) }
+        ; return (SigPatOut pat' inner_ty, tvs, res) }
+
+-- Use this when we add pattern coercions back in
+--       return (mkCoPatCoI (mkSymCoI coi) (SigPatOut pat' inner_ty) pat_ty
+--                 , tvs, res) }
 
 tc_pat _ pat@(TypePat _) _ _
   = failWithTc (badTypePat pat)