pprExpr: don't add extra parens around [a..b] in an argument position

test is tcfail205

diff --git a/compiler/hsSyn/HsExpr.lhs b/compiler/hsSyn/HsExpr.lhs
index 2ddb7c8..db54ab8 100644 (file)
--- a/compiler/hsSyn/HsExpr.lhs
+++ b/compiler/hsSyn/HsExpr.lhs
@@ -529,6 +529,8 @@ pprParendExpr expr
         -- I think that is usually (always?) right
     in
     case unLoc expr of
+      ArithSeq{}           -> pp_as_was
+      PArrSeq{}            -> pp_as_was
       HsLit _              -> pp_as_was
       HsOverLit _          -> pp_as_was
       HsVar _              -> pp_as_was