asanのheap buffer overflowになる

gistfile1.txt

#include <iostream>
using std::cout;
using std::endl;

class Solution {
public:
    int islandPerimeter(vector<vector<int>>& grid) {
        int ans=0;
        for (int i=0;i<grid.size();i++) {
        for (int j=0;j<grid[i].size();j++) {
            for (const auto y : {-1,1}) {
                for (const auto x : {-1, 1}) {
                    if (i+y<0||i+y>=grid.size()||j+x<0||j+y>=grid[i].size()||grid[i+y][j+x]==0) {
                         ans++;
                     }
                }
            }
        }
    }
    return ans;
    }
};