michael@0: // optimized
michael@0: (function(b) {
michael@0:     assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0: })({a:'A', b:'B' });
michael@0: (function() {
michael@0:     var b = {a:'A', b:'B' };
michael@0:     assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0: })();
michael@0: (function() {
michael@0:     let (b = {a:'A', b:'B' }) {
michael@0:         assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0:     }
michael@0: })();
michael@0: (function() {
michael@0:     var b = {a:'A', b:'B' };
michael@0:     (function () {
michael@0:         assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0:     })();
michael@0: })();
michael@0: (function() {
michael@0:     let (b = {a:'A', b:'B' }) {
michael@0:         (function () {
michael@0:             assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0:         })();
michael@0:     }
michael@0: })();
michael@0: (function() {
michael@0:     var b = {a:'A', b:'B' };
michael@0:     (function () {
michael@0:         (function () {
michael@0:             assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0:         })();
michael@0:     })();
michael@0: })();
michael@0: 
michael@0: // not optimized:
michael@0: (function() {
michael@0:     var b = {a:'A', b:'B' };
michael@0:     with ({}) {
michael@0:         (function () {
michael@0:             assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
michael@0:         })();
michael@0:     }
michael@0: })();
michael@0: (function() {
michael@0:    var b = {a:'A', b:'B' };
michael@0:    var bad = function() { b = {a:1, b:2}; return 'X' }
michael@0:    Object.defineProperty(b, 'x', {get:bad});
michael@0:    assertEq("xabc".replace(/x|a|b/g, function(a) { return b[a] }), 'X12c');
michael@0: })();