michael@0: var causeOSI = true;
michael@0: 
michael@0: function rec(x, self) {
michael@0:     if (x === 0 || x !== x) {
michael@0:         if (causeOSI) {
michael@0:             causeOSI = false;
michael@0:             self(NaN, self)
michael@0:             causeOSI = true;
michael@0:         }
michael@0:         return;
michael@0:     }
michael@0:     self(x - 1, self);
michael@0: }
michael@0: 
michael@0: // Use enough iterations to type infer the script.
michael@0: causeOSI = false;
michael@0: for (var i = 0; i < 20; ++i)
michael@0:     rec(1, rec);
michael@0: causeOSI = true;
michael@0: 
michael@0: rec(2, rec)