After JDK-8067139, there's a new compiler warning /Users/attila/Documents/projects/nashorn-jdk9/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/Lower.java:330: warning: [unchecked] unchecked cast [javac] return (T)node.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { [javac] ^ [javac] required: T [javac] found: Node [javac] where T is a type-variable: [javac] T extends Node declared in method <T>ensureUniqueNamesIn(T)