T17646.hs:11:1: warning: [-Wincomplete-patterns (in -Wextra)]
    Pattern match(es) are non-exhaustive
    In an equation for ‘g’: Guards do not cover entire pattern space

T17646.hs:11:5: warning: [-Winaccessible-code (in -Wdefault)]
    • Couldn't match type ‘'True’ with ‘'False’
      Inaccessible code in
        a pattern with constructor: B :: T 'False,
        in a pattern binding in
             a pattern guard for
               an equation for ‘g’
    • In the pattern: B
      In a stmt of a pattern guard for
                     an equation for ‘g’:
        B <- A
      In an equation for ‘g’: g | B <- A = ()

T17646.hs:11:5: warning: [-Woverlapping-patterns (in -Wdefault)]
    Pattern match is redundant
    In an equation for ‘g’: g | B <- A = ...