我正在尝试编写一个parter模块，为此我想连接parsec库。我将依赖项放在package.yaml中，但parsec只在Main.hs中可见。
我的包裹yaml

dependencies:
- base >= 4.7 && < 5
- parsec
ghc-options:
- -Wall
- -Wcompat
- -Widentities
- -Wincomplete-record-updates
- -Wincomplete-uni-patterns
- -Wmissing-export-lists
- -Wmissing-home-modules
- -Wpartial-fields
- -Wredundant-constraints

library:
  source-dirs: src
  dependencies :
    - parsec

executables:
  haskell-lab4-exe:
    main:                Main.hs
    source-dirs:         app
    ghc-options:
    - -threaded
    - -rtsopts
    - -with-rtsopts=-N
    dependencies:
    - haskell-lab4
    - parsec

tests:
  haskell-lab4-test:
    main:                Spec.hs
    source-dirs:         test
    ghc-options:
    - -threaded
    - -rtsopts
    - -with-rtsopts=-N
    dependencies:
    - haskell-lab4

项目的结构如下所示（它是使用stack new创建的）

|-app
|  \- Main.hs
|
|-src
|  \-Parser
|   |    \-Myfile.hs <-- I need parsec in this file
|   | 
|   |-Lib.hs
|
|-test

错误：

Could not find module ‘Text.Parsec.String.Combinator’
    Perhaps you meant Text.Parsec.Combinator (from parsec-3.1.15.0)
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.