tcfail137.hs:1:14: warning: [-Wdeprecated-flags (in -Wdefault)]
    -XDatatypeContexts is deprecated: It was widely considered a misfeature, and has been removed from the Haskell language.

tcfail137.hs:8:5: error: [GHC-39999]
    • No instance for ‘Floating Bool’ arising from a use of ‘Test’
    • In the expression: Test [False, True]
      In an equation for ‘x’: x = Test [False, True]