堆栈构建失败，“未能加载”`main“接口，没有找到匹配‘`Main’的单元id”

Question

我一直试图改变一个项目，以同时提供一个库(以前它只是一个可执行文件)。

唯一的更改是(对hpack package.yaml)：

+library:
+  source-dirs: src
+  exposed-modules:
+    - CYAva

但是，现在在运行stack build时，我看到了以下输出：

2018-12-31 16:32:06.406901: [warn] Failed to load interface for `Main'
2018-12-31 16:32:06.407023: [warn] no unit id matching `main' was found

hpack文件：

library:
  source-dirs: src
  exposed-modules:
    - CYAva
executable:
  source-dirs: src
  main: Main.hs
license-file: LICENSE
build-type: Simple
maintainer: Chris Stryczynski
dependencies:
- base >=4.10 && <4.12
- colour
- data-default-class
# common
- Chart-cairo
- Chart
- lens
- aeson
- bytestring
- stm
- split
- text
- time
- thyme
- binary
- binary-orphans
- old-locale
- directory
- pretty-simple
- string-conversions
- optparse-applicative
name: ceriumyankeeavocado
version: '0.1.0.0'
extra-source-files: ChangeLog.md
author: Chris Stryczynski
license: BSD3

阴谋集团档案：

cabal-version: 1.12

-- This file has been generated from package.yaml by hpack version 0.31.1.
--
-- see: https://github.com/sol/hpack
--
-- hash: d90f1b53fc8bb74ddff9cf98937222e0c38a20affcd2506880039312e549541f

name:           ceriumyankeeavocado
version:        0.1.0.0
author:         Chris Stryczynski
maintainer:     Chris Stryczynski
license:        BSD3
license-file:   LICENSE
build-type:     Simple
extra-source-files:
    ChangeLog.md

library
  exposed-modules:
      CYAva
  other-modules:
      Main
      Paths_ceriumyankeeavocado
  hs-source-dirs:
      src
  build-depends:
      Chart
    , Chart-cairo
    , aeson
    , base >=4.10 && <4.12
    , binary
    , binary-orphans
    , bytestring
    , colour
    , data-default-class
    , directory
    , lens
    , old-locale
    , optparse-applicative
    , pretty-simple
    , split
    , stm
    , string-conversions
    , text
    , thyme
    , time
  default-language: Haskell2010

executable ceriumyankeeavocado
  main-is: Main.hs
  other-modules:
      CYAva
      Paths_ceriumyankeeavocado
  hs-source-dirs:
      src
  build-depends:
      Chart
    , Chart-cairo
    , aeson
    , base >=4.10 && <4.12
    , binary
    , binary-orphans
    , bytestring
    , colour
    , data-default-class
    , directory
    , lens
    , old-locale
    , optparse-applicative
    , pretty-simple
    , split
    , stm
    , string-conversions
    , text
    , thyme
    , time
  default-language: Haskell2010

stack build

thyme-0.3.5.5: configure
thyme-0.3.5.5: build
Chart-1.9: configure
Chart-1.9: build
Chart-1.9: copy/register
Chart-cairo-1.9: configure                  
Chart-cairo-1.9: build                      
Chart-cairo-1.9: copy/register              
thyme-0.3.5.5: copy/register                
Building all executables for `ceriumyankeeavocado' once. After a successful build of all of them, only specified executables will be rebuilt.
ceriumyankeeavocado-0.1.0.0: configure (lib + exe)
Configuring ceriumyankeeavocado-0.1.0.0...
ceriumyankeeavocado-0.1.0.0: build (lib + exe)
Preprocessing executable 'ceriumyankeeavocado' for ceriumyankeeavocado-0.1.0.0..
Building executable 'ceriumyankeeavocado' for ceriumyankeeavocado-0.1.0.0..
[1 of 3] Compiling CYAva            ( src/CYAva.hs, .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/ceriumyankeeavocado/ceriumyankeeavocado-tmp/CYAva.o )
[2 of 3] Compiling Main             ( src/Main.hs, .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/ceriumyankeeavocado/ceriumyankeeavocado-tmp/Main.o )
[3 of 3] Compiling Paths_ceriumyankeeavocado ( .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/ceriumyankeeavocado/autogen/Paths_ceriumyankeeavocado.hs, .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/ceriumyankeeavocado/ceriumyankeeavocado-tmp/Paths_ceriumyankeeavocado.o )
Linking .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/ceriumyankeeavocado/ceriumyankeeavocado ...
Preprocessing library for ceriumyankeeavocado-0.1.0.0..
Building library for ceriumyankeeavocado-0.1.0.0..
[1 of 3] Compiling CYAva            ( src/CYAva.hs, .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/CYAva.o )
[2 of 3] Compiling Main             ( src/Main.hs, .stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/Main.o )
Failed to load interface for `Main'      
no unit id matching `main' was found     
Completed 4 action(s).                   

--  While building package ceriumyankeeavocado-0.1.0.0 using:
      /home/chris/.stack/setup-exe-cache/x86_64-linux-nix/Cabal-simple_mPHDZzAJ_2.2.0.1_ghc-8.4.3 --builddir=.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1 build lib:ceriumyankeeavocado exe:ceriumyankeeavocado --ghc-options " -ddump-hi -ddump-to-file -fdiagnostics-color=always"

Answer 1

我的Main.hs文件中没有以下内容：

module Main where

上面的改动把它修好了。