Before: call ale#assert#SetUpLinterTest('haskell', 'ghc') After: call ale#assert#TearDownLinterTest() Execute(The options should be used in the command): AssertLinter 'ghc', 'ghc -fno-code -v0 %t' let b:ale_haskell_ghc_options = 'foobar' AssertLinter 'ghc', 'ghc foobar %t'