Avoid NPE in ProceedOnErrorGen

Author: mickaelistria

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/ProceedOnErrorGen.java

@@ -71,6 +71,8 @@ private JCNewClass newRuntimeException() {
 	@Override
 	public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
 		try {
+			// avoid possible NPE for incorrect trees
+			//cdef.defs.removeIf(JCErroneous.class::isInstance);
 			return super.genClass(env, cdef) && verifyClassComplete(cdef.sym);
 		} catch (Exception ex) {
 			return false;