How to activate DEBUG in Data.HashTable?

Simon Marlow marlowsd at
Mon Nov 29 12:39:57 CET 2010

On 29/11/2010 02:05, Wolfram Kahl wrote:
> Hello,
>    with a large Agda development, I have a reproducible segmentation fault
> that I have been able to localise to the serialisation
> (Agda.TypeChecking.Serialise.encode), which heavily relies on Data.HashTable.
> Now I find that Data.HashTable (from GHC-7.0.1) has a CPP-enabled DEBUG version ---
> is there a ``proper'' way to activate this? Possibly even so that it can be added
> ex-post to an existing installation? (So I don't have to re-install all packages.)
> mk/ says that the ``debug'' way only affects the RTS...

This is a compile-time option, so there's no way to enable it without 
recompiling the base package (and hence, GHC itself).  However, you can 
always grab a copy of the source code and drop it into your souce tree, 
it will be used in place of the base package version.


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