Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : ghc-7.2

http://hackage.haskell.org/trac/ghc/changeset/108de2a452020f98ee28f7e39c815b0364a8f579

>---------------------------------------------------------------

commit 108de2a452020f98ee28f7e39c815b0364a8f579
Author: David Terei <[email protected]>
Date:   Thu Jul 21 17:29:18 2011 -0700

    Update safe haskell doc about Data.Typeable

>---------------------------------------------------------------

 docs/users_guide/safe_haskell.xml |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/docs/users_guide/safe_haskell.xml 
b/docs/users_guide/safe_haskell.xml
index 07da84f..abca32a 100644
--- a/docs/users_guide/safe_haskell.xml
+++ b/docs/users_guide/safe_haskell.xml
@@ -293,6 +293,12 @@
         compilation error will occur. A simple way to think of this is a
         <emphasis>same origin policy</emphasis> for overlapping instances
         defined in Safe compiled modules.</listitem>
+         <listitem><emphasis>Data.Typeable</emphasis> &mdash; We restrict 
Typeable
+                 instances to only derived ones (offered by GHC through the 
+                 <link 
linkend="deriving-typeable"><option>-XDeriveDataTypeable</option>
+                 </link> extension). Hand crafted instances of the Typeable 
type class
+                 are not allowed in Safe Haskell as this can easily be abused 
to 
+                 unsafely coerce between types.</listitem>
     </itemizedlist>
   </sect2>
 



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