セミコロンが抜けていると怒られるが...

Javascript
1function iftree(x, y, z){
2
3    bi = World.getBlockID(x, y, z);
4    if(bi == 17){
5        return true;
6    }
7    else{
8        return false;
9    }
10}
11
12function addtolist(x, y, z, listname){
13    boolean included = false;
14    //ここでセミコロンが抜けていると怒られる
15    for(let i; i<listname.length; i++){
16        if(listname[i][1] == y){
17            if(listname[i][0] == x){
18                if(listname[i][2] == z){
19                    included = true;
20                }
21            }
22        }
23    }
24    if(included == false){
25        listname.push([x, y, z, 0]);
26    }
27}
28
29
30Callback.addCallback("DestroyBlock", function(coords, block, player){
31    Debug.message(block.id);
32    if(block.id == 17){
33        Debug.message(World.getBlockID(coords.x, coords.y+1, coords.z));
34        blist = [];
35        blist.push([coords.x, coords.y, coords.z, 0]);
36        var cont = true;
37        let count = 0;
38        while(cont){
39            count = 0;
40            for(let i = 0; i < blist.length; i++){
41                if(blist[i][3] == 0){
42                    count += 1;
43                    let _x = blist[i][0];
44                    let _y = blist[i][1];
45                    let _z = blist[i][2];
46                    if(iftree(_x+1, _y, _z)){
47                        addtolist(_x+1, _y, _z, blist);
48                    }
49                    if(iftree(_x-1, _y, _z)){
50                        addtolist(_x-1, _y, _z, blist);
51                    }
52                    if(iftree(_x, _y+1, _z)){
53                        addtolist(_x, _y+1, _z, blist);
54                    }
55                    if(iftree(_x, _y-1, _z)){
56                        addtolist(_x, _y-1, _z, blist);
57                    }
58                    if(iftree(_x, _y, _z+1)){
59                        addtolist(_x, _y, _z+1, blist);
60                    }
61                    if(iftree(_x, _y, _z-1)){
62                        addtolist(_x, _y, _z-1, blist);
63                    }
64                    
65                    blist[i][3] = 1;
66                }
67            }
68            if(count == 0){
69                cont = false;
70            }
71        }
72        for(let i = 0; i < blist.length; i++){
73            World.destroyBlock(blist[i][0], blist[i][1], blist[i][2], true);
74        }
75    } 
76})