GHCI :unset -XLanguageExtension returns "don't know how to reverse -XLanguageExtension"
Any language extension tried appears to not work with :unset. To make matters worse, :unset expands to a number of options, misleading the user into thinking that it should (if that is the case). I eventually had to ask someone on IRC #haskell, leading to the :set -XNoLanguageExtension trick to do what I needed. A fix to :unset is suggested, or removing the misleading/non-working command.
|Test case||:set -XCPP followed by :unset -XCPP|