Cabal sets an ExitFailure 1 roll when creating a Yesod project
I am new to web development and Haskell frameworks and I am following this tutorial . I created yesod init
to create a project. Then I cd'd into the project folder and ran:
$ cabal sandbox init
$ cabal install --enable-tests --reorder-goals --max-backjumps=-1 -j
I ran into several dependency issues here and there, but figured everything out so far. Now I ran into an error during the build process and I cannot find any answers or fixes. The build process ends abruptly with ExitFailure 1
.
Here is the complete error message:
Model.hs:13:1:
Illegal instance declaration for
‘ToBackendKey
persistent-2.0.8:Database.Persist.Sql.Types.SqlBackend Email’
(All instance types must be of the form (T t1 ... tn)
where T is not a synonym.
Use TypeSynonymInstances if you want to disable this.)
In the instance declaration for
‘ToBackendKey persistent-2.0.8:Database.Persist.Sql.Types.SqlBackend Email’
Model.hs:13:1:
Illegal instance declaration for
‘ToBackendKey
persistent-2.0.8:Database.Persist.Sql.Types.SqlBackend User’
(All instance types must be of the form (T t1 ... tn)
where T is not a synonym.
Use TypeSynonymInstances if you want to disable this.)
In the instance declaration for
‘ToBackendKey persistent-2.0.8:Database.Persist.Sql.Types.SqlBackend User’
cabal: Error: some packages failed to install:
Wordscape-0.0.0 failed during the building phase. The exception was:
ExitFailure 1
Has anyone else encountered such an error / knew how to fix it? Any help would be greatly appreciated. Thank!
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