promise-1.js - mozsearch

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// Mutating Promise.prototype.constructor pops the fuse. A no-op change is fine.

newGlobal().evaluate(`

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  let v = Promise.prototype.constructor;

  Promise.prototype.constructor = v;

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  Promise.prototype.constructor = {};

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, false);

`);

// Same for Promise.prototype.then.

newGlobal().evaluate(`

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  let v = Promise.prototype.then;

  Promise.prototype.then = v;

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  Promise.prototype.then = x => x;

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, false);

`);

// Same for Promise.resolve.

newGlobal().evaluate(`

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  let v = Promise.resolve;

  Promise.resolve = v;

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  delete Promise.resolve;

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, false);

`);

// Same for the Promise[@@species] getter.

newGlobal().evaluate(`

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  Object.defineProperty(Promise, Symbol.species, {});

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, true);

  Object.defineProperty(Promise, Symbol.species, {value: null});

  assertEq(getFuseState().OptimizePromiseLookupFuse.intact, false);

`);

assertEq(getUseCounterResults().OptimizePromiseLookupFuse, 4);