michael@0: // Removing a Set entry already visited by an iterator does not cause any
michael@0: // entries to be skipped.
michael@0: 
michael@0: var str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
michael@0: var set = Set(str);
michael@0: 
michael@0: var log = '';
michael@0: var i = 0;
michael@0: for (var x of set) {
michael@0:     log += x;
michael@0:     if (i++ % 5 === 0) {
michael@0:         // Delete all entries preceding this one.
michael@0:         for (let y of set) {
michael@0:             if (y === x)
michael@0:                 break;
michael@0:             set.delete(y);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: assertEq(log, str);
michael@0: assertEq(set.size, 1);  // Elements 0 to 24 are removed, leaving only 25 (Z).
michael@0: assertEq(set.has('Z'), true);