Building ghc on Windows with msys2

Austin Seipp austin at
Tue Oct 7 17:03:54 UTC 2014

On Tue, Oct 7, 2014 at 11:25 AM, cg <chengang31 at> wrote:
> On 9/16/2014 4:57 AM, Gintautas Miliauskas wrote:
>> msys2 seems to be in good shape and should probably be promoted to the
>> primary suggested method to build ghc on Windows. Let's look into that
>> once the new build instructions have been proofread and verified.
> I am trying to build the latest code but without success.
> First, I encounter twe 'Ambiguous occurrence' issues:
> libraries\binary\src\Data\Binary\Builder\Base.hs:110:15:
>   Ambiguous occurrence "empty"
>   It could refer to either "Data.Binary.Builder.Base.empty",
>      defined at libraries\binary\src\Data\Binary\Builder\Base.hs:124:1
>   or "GHC.Base.empty",
>      imported from "GHC.Base" at
> libraries\binary\src\Data\Binary\Builder\Base.hs:84:1-15
> and the same with Prelude.foldr in this Base.hs.
> I hide 'empty' and 'foldr' at importing point and the code compiles.
> Has anyone see the same issues?

Ugh, this is some fallout I thought we had fixed, but apparently not.
I'll fix it shortly, thanks.

> Then, I get this 'out of memory' error at 'building final phase'
> "inplace/bin/ghc-stage1.exe" ... -c
> libraries/Cabal/Cabal/./Language/Haskell/Extension.hs
> ghc-stage1.exe: out of memory
> I am building on Windows 8.1 with 16G ram, with 'BuildFlavour = quick'. And
> I see
> ghc-stage1 is using 16G+ memory in Windows Task Manager.
> Why does ghc-stage1.exe use so much memory?

Wow, I thought we fixed this one too! Please see this bug:

What GHC commit are you using? Are your submodules all up to date? In
particular, if 'binary' is not up to date, even if the rest of your
tree is, you'll see this problem.

> --
> cg
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Austin Seipp, Haskell Consultant
Well-Typed LLP,

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