src/third_party/mozjs-45/js/src/jit-test/tests/symbol/toString.js

// ToString(symbol) throws a TypeError.

var N = 10, obj, hits = 0;
for (var i = 0; i < N; i++) {
    try {
        obj = new String(Symbol());
    } catch (exc) {
        hits++;
    }
}
assertEq(hits, N);