T15233.hs:4:10: error: [GHC-39716]
    Illegal fixity signature of built-in syntax: :

T15233.hs:5:16: error: [GHC-39716]
    Illegal deprecation of built-in syntax: :

T15233.hs:9:10: error: [GHC-39716]
    Illegal fixity signature of built-in syntax: ->