问题
Hello guys i am trying to install ghc-mod for vscode and i am running into this issue:
**$ stack install ghc-mod**
Populated index cache.
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for ghc-mod-5.8.0.0:
Cabal-2.0.1.1 from stack configuration does not match >=1.18 && <1.25 (latest matching version
is 1.24.2.0)
base-4.10.1.0 from stack configuration does not match >=4.6.0.1 && <4.10 (latest matching
version is 4.9.1.0)
mcabal-helper must match <0.8 && >=0.7.3.0, but the stack configuration has no specified version
(latest matching version is 0.7.3.0)
extra-1.6.8 from stack configuration does not match <1.6 && >=1.4 (latest matching version
is 1.5.3)
ghc-8.2.2 from stack configuration does not match >=7.6 && <8.2
haskell-src-exts-1.20.2 from stack configuration does not match <1.20 && >=1.18 (latest
matching version is 1.19.1)
hlint-2.1.6 from stack configuration does not match <2.1 && >=2.0.8 (latest matching version
is 2.0.15)
monad-journal-0.8.1 from stack configuration does not match <0.8 && >=0.4 (latest matching
version is 0.7.2)
optparse-applicative-0.14.2.0 from stack configuration does not match >=0.13.0.0 && <0.14
(latest matching version is 0.13.2.0)
needed since ghc-mod is a build target.
Some different approaches to resolving this:
* Consider trying 'stack solver', which uses the cabal-install solver to attempt to find some
working build configuration. This can be convenient when dealing with many complicated
constraint errors, but results may be unpredictable.
* Recommended action: try adding the following to your extra-deps
in C:\sr\global-project\stack.yaml:
- Cabal-1.24.2.0
- base-4.9.1.0
- cabal-helper-0.7.3.0
- extra-1.5.3
- haskell-src-exts-1.19.1
- hlint-2.0.15
- monad-journal-0.7.2
- optparse-applicative-0.13.2.0
Plan construction failed.
I have tried stack install ghc-mod and cabal install ghc-mod to no avail.I always get this plan construction failed.Any ideas on how to deal with it?
P.S:I have already updated both stack and cabal.
After following the advice of a user i added the files to the C:\sr\global-project/stack.yaml and now it looks like this :
Global stack.yaml :
packages: []
resolver: lts-11.13
Cabal-1.24.2.0
base-4.9.1.0
cabal-helper-0.7.3.0
extra-1.5.3
haskell-src-exts-1.19.1
hlint-2.0.15
monad-journal-0.7.2
optparse-applicative-0.13.2.0
After i added all these files i get the following error when running stack install ghc-mod :
$ stack install ghc-mod
Unable to load custom resolver lts-11.13 Cabal-1.24.2.0 base-4.9.1.0 cabal-helper-0.7.3.0 extra-1.5.3 haskell-src-exts-1.19.1 hlint-2.0.15 monad-journal-0.7.2 optparse-applicative-0.13.2.0 from local file:
C:\sr\global-project\lts-11.13 Cabal-1.24.2.0 base-4.9.1.0 cabal-helper-0.7.3.0 extra-1.5.3 haskell-src-exts-1.19.1 hlint-2.0.15 monad-journal-0.7.2 optparse-applicative-0.13.2.0
Exception: InvalidYaml (Just (YamlException "Yaml file not found: C:\\sr\\global-project\\lts-11.13 Cabal-1.24.2.0 base-4.9.1.0 cabal-helper-0.7.3.0 extra-1.5.3 haskell-src-exts-1.19.1 hlint-2.0.15 monad-journal-0.7.2 optparse-applicative-0.13.2.0"))
回答1:
The problem is that ghc-mod does not work on ghc-8.2. The latest Stack resolver that supports ghc-mod seems to be lts-9.21.
ghc-mod has to be compiled with the same version of GHC you are using, so right now that constrains you to 8.0.
回答2:
ghc-mod is clearly unused by most people working with the latest toolchain or else this would work. Consider abandoning it too.
来源：https://stackoverflow.com/questions/51293944/can-not-install-ghc-mod