constant-compare-with-undefined.js

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function test1(v) {

  var undefined = v;

  assertEq(v === undefined, true);

  assertEq(v !== undefined, false);

  (function inner(a) {

    assertEq(a === undefined, true);

    assertEq(a !== undefined, false);

  })(v);

test1(1);

function test2() {

  var envChainObject = {undefined: 1};

  evaluate(`var x = 1; var res1 = x === undefined; var res2 = x !== undefined;`,

           {envChainObject});

  assertEq(envChainObject.res1, true);

  assertEq(envChainObject.res2, false);

test2();