Opencv ptr()'s overload 9 and 10

C++
1

https://docs.opencv.org/master/d3/d63/classcv_1_1Mat.html#a7ce1d8cc9a83ae7cab79766d0eb6c0a8

Mat mat = (Mat_<int>{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}).reshape(2, 3);
const Vec<int,2> vi2{1,1};
mat.ptr(vi2);
error: mat.ptr<2>(Vec2i) undefined ,the source code just exactly decalre,but undefined .

Any help is appreciated.