T18240a.hs:11:11: error:
    • Instance head cannot contain nested ‘forall’s or contexts
    • In an instance declaration

T18240a.hs:12:15: error: [GHC-76037]
    Not in scope: type variable ‘a’

T18240a.hs:14:11: error:
    • Instance head cannot contain nested ‘forall’s or contexts
    • In an instance declaration

T18240a.hs:17:11: error:
    • Instance head cannot contain nested ‘forall’s or contexts
    • In an instance declaration

T18240a.hs:18:22: error: [GHC-76037]
    Not in scope: type variable ‘a’

T18240a.hs:20:21: error:
    • Instance head cannot contain nested ‘forall’s or contexts
    • In an instance declaration

T18240a.hs:21:24: error: [GHC-76037]
    Not in scope: type variable ‘b’

T18240a.hs:23:19: error:
    • Instance head cannot contain nested ‘forall’s or contexts
    • In an instance declaration

T18240a.hs:28:10: error: [GHC-12222]
    • Illegal head of an instance declaration: ‘42’
        Instance heads must be of the form
          C ty_1 ... ty_n
        where ‘C’ is a class
    • In an instance declaration

T18240a.hs:29:10: error: [GHC-12222]
    • Illegal head of an instance declaration: ‘Int -> Int’
        Instance heads must be of the form
          C ty_1 ... ty_n
        where ‘C’ is a class
    • In an instance declaration