From: simonmar <unknown>
Date: Thu, 17 Aug 2000 16:28:44 +0000 (+0000)
Subject: [project @ 2000-08-17 16:28:44 by simonmar]
X-Git-Tag: Approximately_9120_patches~3867
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=bb8442c975cd6b9f70c3f15cc09b2925594b11e1;p=ghc-hetmet.git

[project @ 2000-08-17 16:28:44 by simonmar]
Replace a zipEqual with a zip in tcPat when checking a record pat.
The former version caused a panic with DEBUG on if a record pattern
was used with a non-record constructor.
---

diff --git a/ghc/compiler/typecheck/TcPat.lhs b/ghc/compiler/typecheck/TcPat.lhs
index e0cb157..e5b8847 100644
--- a/ghc/compiler/typecheck/TcPat.lhs
+++ b/ghc/compiler/typecheck/TcPat.lhs
@@ -213,9 +213,11 @@ tcPat tc_bndr pat@(RecPatIn name rpats) pat_ty
  	-- Check the constructor itself
     tcConstructor pat name pat_ty	`thenTc` \ (data_con, ex_tvs, dicts, lie_avail1, arg_tys) ->
     let
-	field_tys = zipEqual "tcPat" 
-			     (map fieldLabelName (dataConFieldLabels data_con))
-			     arg_tys
+	-- not zipEqual: if the constructor isn't really a record, then
+	-- dataConFieldLabels will be empty (and each field in the pattern
+	-- will generate an error below).
+	field_tys = zip (map fieldLabelName (dataConFieldLabels data_con))
+			arg_tys
     in
 
 	-- Check the fields