Merge pull request #1742 from typetetris/master

Add cabal-ghc linter

test/command_callback/test_haskell_cabal_ghc_command_callbacks.vader

@@ -0,0 +1,23 @@
+Before:
+  Save g:ale_haskell_cabal_ghc_options
+
+  unlet! g:ale_haskell_cabal_ghc_options
+  unlet! b:ale_haskell_cabal_ghc_options
+
+  runtime ale_linters/haskell/cabal_ghc.vim
+
+After:
+  Restore
+  unlet! b:ale_haskell_cabal_ghc_options
+  call ale#linter#Reset()
+
+Execute(The options should be used in the command):
+  AssertEqual
+  \ 'cabal exec -- ghc -fno-code -v0 %t',
+  \ ale_linters#haskell#cabal_ghc#GetCommand(bufnr(''))
+
+  let b:ale_haskell_cabal_ghc_options = 'foobar'
+
+  AssertEqual
+  \ 'cabal exec -- ghc foobar %t',
+  \ ale_linters#haskell#cabal_ghc#GetCommand(bufnr(''))