docs: public static Supplier<ExpressionTree> receiverInstance() {
      return new Supplier<ExpressionTree>() {
        @Override
        public ExpressionTree get(VisitorState state) {
          MethodInvocationTree method = (MethodInvocationTree) state.getPath().getLeaf();
          return ((JCFieldAccess) method.getMethodSelect()).getExpression();
        }
      };
    }