[Haskell-cafe] .hi inconsistency bug.

Joe Fredette jfredett at gmail.com
Wed Mar 18 00:52:08 EDT 2009

So, if I understand correctly, the interpreter is compiling MainTypes 

Could this be a result of having two outputs (one executable and one 
library) in my .cabal file? it _does_ compile those things twice... If I 
create a second cabal file which separates these two different packages, 
would that fix it?

The issue is, the (dynamic) interpreter part of my code is part of the 
main loop of the program, and is (as far as I can see) inseparable from 
the rest of the code.

I'll give the cabal thing a try, given the incredible triviality of 
doing everything with cabal, I should be done testing the solution 
before I hit the send button... Cabal guys, you rock.

Thanks again, Dan.


Daniel Gorín wrote:
> Hi
> Just a wild guess but maybe the interpreter is recompiling (in 
> runtime) code that has already been compiled to build your application 
> (in compile-time). This may lead to inconsistencies since a type such 
> as HackMail.Data.Main.Types.Filter may refer to two different (and 
> incompatible) types.
> To see if this is the case, make sure your "dynamic" code is not 
> located together with your base code (i.e., move it to another 
> directory, and set the src file directory for the interpreter 
> accordingly). Now you may get another runtime error, something along 
> the lines of "Module not found: HackMail.Data.MainTypes". This 
> basically means that you need to make your (already compiled) types 
> available to the interpreter. I think the simplest way is to put all 
> your support types in a package, register it with ghc, link your 
> application to it, and ask the interpreter to use this package (with a 
> "-package " flag).
> Hope this helps!
> Daniel
> On Mar 17, 2009, at 11:52 PM, Joe Fredette wrote:
>> List,
>> I've got this project, source on patch-tag here[1]
>> It's a nice little project, I've got the whole thing roughly working, 
>> it compiles okay, everything seems to work, until I try to run it, 
>> specifically when I run it in ghci, or when I run the main executable 
>> (which uses hint), and look at any type involving my "Email" type, it 
>> gives me the following error:
>>  Type syonym HackMail.Data.MainTypes.Filter:
>>    Can't find interface-file declaration for type constructor or 
>> class HackMail.Data.ParseEmail.Email
>>      Probable cause: bug in .hi-boot file, or inconsistent .hi file
>>      Use -ddump-if-trace to get an idea of which file caused the error
>> As far as I understand, it wants to find the interface-file 
>> declaration for a specific type (Email) exported by the ParseEmail 
>> module, all of the exports (I think) are in order. I've tried mucking 
>> around with it a bit, but I don't fully understand what the error 
>> even means, much less how to fix it.
>> Other relevant info, Email is exported in a roundabout way, namely by 
>> importing a module MainTypes, which exports a module Email, which 
>> exports a the ParseEmail Module, which exports the datatype Email.
>> The "Filter" delcaration it _actually_ complains about (it's just the 
>> first place the email type is invoked) is:
>>  type Filter a = ReaderT (Config, Email) IO a
>> nothing particularly special.
>> Any help fixing this is greatly appreciated, I did find this bug 
>> report[2] which seems like it might be relevant.
>> But trying to unregister -> cabal clean -> cabal install doesn't fix 
>> it. I've also tried manually removing the dist/ folder, and also 
>> unregistering the package.
>> Thanks again.
>> /Joe
>> [1] http://patch-tag.com/repo/Hackmail/browse
>> [2] http://hackage.haskell.org/trac/ghc/ticket/2057
>> <jfredett.vcf>_______________________________________________
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