From: Ian Lynagh <igloo@earth.li>
Date: Sun, 16 Nov 2008 16:02:28 +0000 (+0000)
Subject: Change an "undefined" into a more informative error; trac #2782
X-Git-Tag: 2009-06-25~98
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=84b66ed4bae2f14c99eed74b1d40edc35f8e2b84;p=ghc-base.git

Change an "undefined" into a more informative error; trac #2782
---

diff --git a/Data/Data.hs b/Data/Data.hs
index 0ef5fd3..930fcdd 100644
--- a/Data/Data.hs
+++ b/Data/Data.hs
@@ -432,7 +432,7 @@ newtype Mp m x = Mp { unMp :: m (x, Bool) }
 
 -- | Build a term skeleton
 fromConstr :: Data a => Constr -> a
-fromConstr = fromConstrB undefined
+fromConstr = fromConstrB (error "Data.Data.fromConstr")
 
 
 -- | Build a term and use a generic function for subterms