Haskell Yesod problems

问题:

someone could help me?! I'm working in a Haskell Yesod site for college on a C9 workspace, I've already installed by command Yesod and update cabal, but when I try "stack build" command, this miserable error message appears:

 $ stack build

aulahaskell-0.0.0: build (lib + exe)
Preprocessing library aulahaskell-0.0.0...
[ 7 of 13] Compiling Handler.Cliente  ( src/Handler/Cliente.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.2.0/build/Handler/Cliente.o )

/home/ubuntu/workspace/web2017/src/Handler/Cliente.hs:10:1: error:
    Failed to load interface for ‘Network.HTTP.Types.Status’
    It is a member of the hidden package ‘http-types-0.9.1’.
    Perhaps you need to add ‘http-types’ to the build-depends in your .cabal file.
    Use -v to see a list of the files searched for.

--  While building package aulahaskell-0.0.0 using:
      /home/ubuntu/.stack/setup-exe-cache/x86_64-linux/Cabal-simple_mPHDZzAJ_1.24.2.0_ghc-8.0.2 --builddir=.stack-work/dist/x86_64-linux/Cabal-1.24.2.0 build lib:aulahaskell exe:aulahaskell --ghc-options " -ddump-hi -ddump-to-file"
    Process exited with code: ExitFailure 1

Seriously, I tried a bunch of things to fix it, but nothing is working =S

回答1:

Just read the error message carefully:

Failed to load interface for ‘Network.HTTP.Types.Status’
It is a member of the hidden package ‘http-types-0.9.1’.
Perhaps you need to add ‘http-types’ to the build-depends in your .cabal file.
Use -v to see a list of the files searched for.

The line Perhaps you need to add ‘http-types’ to the build-depends in your .cabal file tells you what to do: You must add http-types to the build-depends: section of the library aulahaskell in your cabal file.

If this does not help, please post your cabal file.

回答2:

How did you start the yesod project? It's recommended to do:

stack new my-yesod-project yesod-(your database here)
cd my-yesod-project
stack build

回答3:

Thank you, guys! It was a problem on how I was starting the project, some files weren't installed on my workspace, so I delete the files, reinstall Yesod and cabal, create another new version after following this steps: https://www.yesodweb.com/page/quickstart