GHC 6.4 release candidates available

Simon Marlow simonmar at
Mon Feb 14 07:37:52 EST 2005

On 12 February 2005 07:32, John Meacham wrote:

> On Fri, Feb 11, 2005 at 10:49:56AM -0000, Simon Marlow wrote:
>> GHC has warned you about a module clash, for which you should be
>> grateful :-)  This could have lead to strange link-time errors, or
>> even crashes, if you had used a library module which depended on the
>> other PackedString. 
>> The golden rule is (from the new section on packages in the GHC
>> User's Guide): 
>>   There must be no overlaps in the modules provided by all of the
>>   exposed packages, and the packages they depend on, and so on.
>> PackedString (not Data.PackedString) is indeed a member of the
>> lang-1.0 package.  This normally wouldn't be a problem, because lang
>> is hiden. However, if lang is a dependency of some other exposed
>> package, then it becomes part of your program, and hence its modules
>> cannot overlap with any others.  What other packages are you using?
> Ah, changing some code to use the hierarchical libraries and getting
> rid of my other package imports seems to have fixed things. cool.
> Does this mean I have been getting silent brokeness in the past due
> to the nameing conflict?

Probably not, but you've been walking on thin ice.


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