JastAddJ 7.1.1-312-gb3bf40c Java SE 8
JastAddJ allows the second part of an instanceof expression to reference a non-reifiable type. This goes against the JLS. See for example JLS SE7 $15.20.2:
It is a compile-time error if the ReferenceType mentioned after the instanceof operator does not denote a reference type that is reifiable (§4.7).