T14141_Unsat.hs:26:1: warning: [GHC-94210] [-Woverlapping-patterns (in -Wdefault)]
    Pattern match has inaccessible right hand side
    In an equation for ‘f’: f MkD = ...

T14141_Unsat.hs:41:1: warning: [GHC-53633] [-Woverlapping-patterns (in -Wdefault)]
    Pattern match is redundant
    In an equation for ‘exhaustive’: exhaustive B = ...