Help with build ordering issue

Ben Gamari ben at
Mon Feb 26 18:19:54 UTC 2018

Sylvain Henry <sylvain at> writes:

> On 25/02/2018 21:30, Ben Gamari wrote:
>> Hmm, I'm afraid that's not particularly illuminating.
>> It would be helpful to see the output from -ddump-if-trace as this will
>> tell you why GHC is trying to load this interface file.
> Thanks, it has been helpful. The relevant trace is:
> Need decl for mkNatural
> Considering whether to load GHC.Natural {- SYSTEM -}
> Reading interface for base-;
>      reason: Need decl for mkNatural
> readIFace libraries/base/dist-install/build/GHC/Natural.hi
> Now I still don't know why GHC is trying to load the interface of the 
> module it is compiling.

Keep in mind that GHC may call upon mkNatural while typechecking even
without an import as it is known-key. The output of -ddump-tc-trace
might also help identify whether this is the case.

I would help if there were some way I could reproduce this.


- Ben

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