*     visit(t.getGenericComponentType());
 *   }
 *   protected void visitTypeVariable(TypeVariable<?> t) {
 *     throw new IllegalArgumentException("Cannot contain type variable.");
 *   }
 *   protected void visitWildcardType(WildcardType t) {
 *     throw new IllegalArgumentException("Cannot contain wildcard type.");
 *   }
 * }.visit(type);
 * }
 *