Unknown flag in GHC options pragma [GHC-04924]

A flag was found in the OPTIONS_GHC pragma that was not known; the list of all possible GHC flags is here.

Examples

Unknown flag in {-\# OPTIONS_GHC \#-} pragma

A flag was found in the OPTIONS_GHC pragma that was not known.

Error Message

UnknownOptionsFlag.hs:1:16: error: [GHC-04924]
    unknown flag in  {-# OPTIONS_GHC #-} pragma: -flat-specialise
  |
1 | {-# OPTIONS_GHC -flat-specialise #-}
  |                ^^^^^^^^^^^^^^^^^^
UnknownOptionsFlag.hs
Before
{-# OPTIONS_GHC -flat-specialise #-}

module UnknownOptionsFlag where
After
{-# OPTIONS_GHC -flate-specialise #-}

module UnknownOptionsFlag where