t4457_1.scala:27: error: ambiguous reference to overloaded definition,
both method aFunc in object ImplicitConvAmbiguity2 of type [A](a: ImplicitConvAmbiguity2.NZ[A])ImplicitConvAmbiguity2.AA[Float]
and  method aFunc in object ImplicitConvAmbiguity2 of type [A](a: ImplicitConvAmbiguity2.NE[A])ImplicitConvAmbiguity2.AA[A]
match argument types (Float)
    val x = aFunc(4F)
            ^
one error found