The Tor Browser / file revision

 // vim: set ts=8 sts=4 et sw=4 tw=99:

 function w(y)

 {

     var x = 23.5;

     return x & y;

 }

 function f(x, y) {

     // Confuse the type analysis to not know the type of x.

     var t = 3.5 + x;

     t + 3.5;

     return x & y;

 }

 function g_bool(x, y) {

     var t;

     if (x + 0)

         t = true;

     else

         t = false;

     return t & y;

 }

 function g_null(x) {

     return null & x;

 }

 var obj = { valueOf: function () { return 5; } }

 assertEq(w(93), 21);

 assertEq(g_bool(1, 3), 1);

 assertEq(g_bool(0, 3), 0);

 assertEq(g_null(2), 0);

 assertEq(f(1, 7), 1);

 assertEq(f(true, 7), 1);

 assertEq(f(false, 7), 0);

 assertEq(f("3", 7), 3);

 assertEq(f(obj, 7), 5);

 assertEq(f(3.5, 7), 3);

 assertEq(f(undefined, 7), 0);

 assertEq(f(null, 7), 0);

 assertEq(f(Math.NaN, 7), 0);