The Tor Browser / file revision

 let expected = 'o!o!o!';

 let actual = '';

 // g is a function that needs an implicit |this| if called within a |with|

 // statement.  If we fail to provide that implicit |this|, it will append

 // "[object global]" instead of "o!".

 let o = {

   g: function() { actual += this.toString(); },

   toString: function() { return "o!"; }

 }

 // g's presence within the |with| is detected by simple tracking of |with|s

 // during parsing.

 with (o) {

   (function() { g(); })();

 }

 // The eval() defeats the tracking of |with| during parsing.  Instead, g's

 // presence within the |with| is detected by looking at the scopeChain of the

 // ParseContext.

 with (o) {

   eval("(function() { g(); })()");

 }

 // This is like the above case, but the knowledge of the |with| presence must

 // be inherited by the inner function.  This is the case that was missed in bug

 // 786114.

 with (o) {

   eval("(function() { (function() { g(); })(); })()");

 }

 assertEq(actual, expected);