==== tests/cases/compiler/forIn.ts (2 errors) ====
    var arr = null;
    for (var i:number in arr) { // error
             ~
!!! The left-hand side of a 'for...in' statement cannot use a type annotation.
        var x1 = arr[i];
        var y1 = arr[i];
    }
    
    for (var j in arr) { // ok
        var x2 = arr[j];
        var y2 = arr[j];
    }
    
    var arr2 = [];
    for (j in arr2) { // ok
        var x3 = arr2[j];
        var y3 = arr2[j];
    }
    
    for (var l in arr) { 
       // error in the body
       k[l] = 1;
       ~
!!! Cannot find name 'k'.
    }