T14719.hs:5:3: error:
    • Data constructor ‘MkFoo1’ returns type ‘Bool’
        instead of an instance of its parent type ‘Foo1’
    • In the definition of data constructor ‘MkFoo1’
      In the data type declaration for ‘Foo1’
  |
5 |   MkFoo1 :: Bool
  |   ^^^^^^^^^^^^^^

T14719.hs:8:3: error: [GHC-23517]
    • A newtype constructor must have exactly one field
        but ‘MkFoo2’ has none
      MkFoo2 :: Foo2
    • In the definition of data constructor ‘MkFoo2’
      In the newtype declaration for ‘Foo2’
  |
8 |   MkFoo2 :: Foo2
  |   ^^^^^^^^^^^^^^