code: public Expression accessor() {
      checkState(isStatic());
      Features features = Features.of(Feature.CHEAP);
      if (!isNullable()) {
        features = features.plus(Feature.NON_NULLABLE);
      }
      return new Expression(type(), features) {
        @Override
        protected void doGen(CodeBuilder mv) {
          accessStaticUnchecked(mv);
        }
      };
    }
docs: Returns an expression that accesses this static field.