pmc005.hs:11:1: warning: [-Wincomplete-patterns (in -Wextra)]
    Pattern match(es) are non-exhaustive
    In an equation for ‘foo’: Patterns not matched: TBool TBool

pmc005.hs:12:1: warning: [-Woverlapping-patterns (in -Wdefault)]
    Pattern match has inaccessible right hand side
    In an equation for ‘foo’: foo _ TList = ...