NormalizeTest.java

/*
 * Copyright 2008 The Closure Compiler Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.javascript.jscomp;

import static com.google.common.truth.Truth.assertThat;

import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.rhino.Node;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;

/**
 * @author johnlenz@google.com (John Lenz)
 *
 */
public final class NormalizeTest extends CompilerTestCase {

  private static final String EXTERNS = "var window; var Arguments;";

  public NormalizeTest() {
    super(EXTERNS);
  }

  @Override
  protected void setUp() throws Exception {
    super.setUp();
    setAcceptedLanguage(LanguageMode.ECMASCRIPT_2017);
  }

  @Override
  protected CompilerPass getProcessor(final Compiler compiler) {
    return new Normalize(compiler, false);
  }

  @Override
  protected int getNumRepetitions() {
    // The normalize pass is only run once.
    return 1;
  }

  public void testSplitVar() {
    testSame("var a");
    test("var a, b",
        "var a; var b");
    test("var a, b, c",
        "var a; var b; var c");
    testSame("var a = 0 ");
    test("var a = 0 , b = foo()",
        "var a = 0; var b = foo()");
    test("var a = 0, b = 1, c = 2",
        "var a = 0; var b = 1; var c = 2");
    test("var a = foo(1), b = foo(2), c = foo(3)",
        "var a = foo(1); var b = foo(2); var c = foo(3)");

    test("try{var b = foo(1), c = foo(2);} finally { foo(3) }",
        "try{var b = foo(1); var c = foo(2)} finally { foo(3); }");
    test("try{var b = foo(1),c = foo(2);} finally {}",
        "try{var b = foo(1); var c = foo(2)} finally {}");
    test("try{foo(0);} finally { var b = foo(1), c = foo(2); }",
        "try{foo(0);} finally {var b = foo(1); var c = foo(2)}");

    test("switch(a) {default: var b = foo(1), c = foo(2); break;}",
        "switch(a) {default: var b = foo(1); var c = foo(2); break;}");

    test("do var a = foo(1), b; while(false);",
        "do{var a = foo(1); var b} while(false);");
    test("a:var a,b,c;",
        "a:{ var a;var b; var c; }");
    test("if (true) a:var a,b;",
        "if (true)a:{ var a; var b; }");
  }

  public void testSplitVar_forLoop() {
    // Verify vars extracted from FOR nodes are split.
    test(
        "for(var a = 0, b = foo(1), c = 1; c < b; c++) foo(2)",
        "var a = 0; var b = foo(1); var c = 1; for(; c < b; c++) foo(2)");

    // Verify split vars properly introduce blocks when needed.
    test("for(;;) var b = foo(1), c = foo(2);", "for(;;){var b = foo(1); var c = foo(2)}");
    test("for(;;){var b = foo(1), c = foo(2);}", "for(;;){var b = foo(1); var c = foo(2)}");

    test("a:for(var a,b,c;;);", "var a;var b; var c;a:for(;;);");
  }

  public void testSplitLet() {
    testSame("let a");
    test("let a, b", "let a; let b");
    test("let a, b, c", "let a; let b; let c");
    testSame("let a = 0 ");
    test("let a = 0 , b = foo()", "let a = 0; let b = foo()");
    test("let a = 0, b = 1, c = 2", "let a = 0; let b = 1; let c = 2");
    test(
        "let a = foo(1), b = foo(2), c = foo(3)", "let a = foo(1); let b = foo(2); let c = foo(3)");
    testSame("for (let a = 0, b = 1;;) {}");
  }

  public void testLetManyBlocks() {
    test(
        LINE_JOINER.join(
            "let a = 'outer';",
            "{ let a = 'inner1'; }",
            "{ let a = 'inner2'; }",
            "{ let a = 'inner3'; }",
            "{ let a = 'inner4'; }"),
        LINE_JOINER.join(
            "let a = 'outer';",
            "{ let a$jscomp$1 = 'inner1'; }",
            "{ let a$jscomp$2 = 'inner2'; }",
            "{ let a$jscomp$3 = 'inner3'; }",
            "{ let a$jscomp$4 = 'inner4'; }"));
  }

  public void testLetOutsideAndInsideForLoop() {
    test(
        LINE_JOINER.join(
            "let a = 'outer';",
            "for (let a = 'inner';;) {",
            "  break;",
            "}",
            "alert(a);"),
        LINE_JOINER.join(
            "let a = 'outer';",
            "for (let a$jscomp$1 = 'inner';;) {",
            "  break;",
            "}",
            "alert(a);"));
  }

  public void testLetOutsideAndInsideBlock() {
    test(
        LINE_JOINER.join(
            "let a = 'outer';",
            "{",
            "  let a = 'inner';",
            "}",
            "alert(a);"),
        LINE_JOINER.join(
            "let a = 'outer';",
            "{",
            "  let a$jscomp$1 = 'inner';",
            "}",
            "alert(a);"));
  }

  public void testLetOutsideAndInsideFn() {
    test(
        LINE_JOINER.join(
            "let a = 'outer';",
            "function f() {",
            "  let a = 'inner';",
            "}",
            "alert(a);"),
        LINE_JOINER.join(
            "let a = 'outer';",
            "function f() {",
            "  let a$jscomp$1 = 'inner';",
            "}",
            "alert(a);"));
  }

  public void testRemoveEmptiesFromClass() {
    test(
        LINE_JOINER.join(
            "class Foo {",
            "  m1() {};",
            "  m2() {};",
            "}"),
        LINE_JOINER.join(
            "class Foo {",
            "  m1() {}",
            "  m2() {}",
            "}"));
  }

  public void testClassInForLoop() {
    testSame("for (class a {};;) { break; }");
  }

  public void testFunctionInForLoop() {
    testSame("for (function a() {};;) { break; }");
  }

  public void testLetInGlobalHoistScope() {
    testSame(
        LINE_JOINER.join(
            "if (true) {",
            "  let x = 1; alert(x);",
            "}"));

    test(
        LINE_JOINER.join(
            "if (true) {",
            "  let x = 1; alert(x);",
            "} else {",
            "  let x = 1; alert(x);",
            "}"),
        LINE_JOINER.join(
            "if (true) {",
            "  let x = 1; alert(x);",
            "} else {",
            "  let x$jscomp$1 = 1; alert(x$jscomp$1);",
            "}"));
  }

  public void testConstInGlobalHoistScope() {
    testSame(
        LINE_JOINER.join(
            "if (true) {",
            "  const x = 1; alert(x);",
            "}"));

    test(
        LINE_JOINER.join(
            "if (true) {",
            "  const x = 1; alert(x);",
            "} else {",
            "  const x = 1; alert(x);",
            "}"),
        LINE_JOINER.join(
            "if (true) {",
            "  const x = 1; alert(x);",
            "} else {",
            "  const x$jscomp$1 = 1; alert(x$jscomp$1);",
            "}"));
  }

  public void testVarReferencedInHoistedFunction() {
    test(
        LINE_JOINER.join(
            "var f1 = function() {",
            "  var x;",
            "};",
            "",
            "(function () {",
            "  {",
            "    var x = 0;",
            "  }",
            "  function f2() {",
            "    alert(x);",
            "  }",
            "  f2();",
            "})();"),
        LINE_JOINER.join(
            "var f1 = function() {",
            "  var x;",
            "};",
            "",
            "(function () {",
            "  function f2() {",
            "    alert(x$jscomp$1);",
            "  }",
            "  {",
            "    var x$jscomp$1 = 0;",
            "  }",
            "  f2();",
            "})();"));
  }

  public void testAssignShorthand() {
    test("x |= 1;", "x = x | 1;");
    test("x ^= 1;", "x = x ^ 1;");
    test("x &= 1;", "x = x & 1;");
    test("x <<= 1;", "x = x << 1;");
    test("x >>= 1;", "x = x >> 1;");
    test("x >>>= 1;", "x = x >>> 1;");
    test("x += 1;", "x = x + 1;");
    test("x -= 1;", "x = x - 1;");
    test("x *= 1;", "x = x * 1;");
    test("x /= 1;", "x = x / 1;");
    test("x %= 1;", "x = x % 1;");

    test("/** @suppress {const} */ x += 1;", "/** @suppress {const} */ x = x + 1;");
  }

  public void testDuplicateVarInExterns() {
    test("var extern;",
        "/** @suppress {duplicate} */ var extern = 3;",
        "/** @suppress {duplicate} */ var extern = 3;");
  }

  public void testUnhandled() {
    testSame("var x = y = 1");
  }

  public void testFor() {
    // Verify assignments are extracted from the FOR init node.
    test("for(a = 0; a < 2 ; a++) foo();",
        "a = 0; for(; a < 2 ; a++) foo()");
    // Verify vars are extracted from the FOR init node.
    test("for(var a = 0; c < b ; c++) foo()",
        "var a = 0; for(; c < b ; c++) foo()");

    // Verify vars are extracted from the FOR init before the label node.
    test("a:for(var a = 0; c < b ; c++) foo()",
        "var a = 0; a:for(; c < b ; c++) foo()");
    // Verify vars are extracted from the FOR init before the labels node.
    test("a:b:for(var a = 0; c < b ; c++) foo()",
        "var a = 0; a:b:for(; c < b ; c++) foo()");

    // Verify block are properly introduced for ifs.
    test("if(x) for(var a = 0; c < b ; c++) foo()",
        "if(x){var a = 0; for(; c < b ; c++) foo()}");

    // Any other expression.
    test("for(init(); a < 2 ; a++) foo();",
        "init(); for(; a < 2 ; a++) foo()");
  }

  public void testForIn1() {
    // Verify nothing happens with simple for-in
    testSame("for(a in b) foo();");

    // Verify vars are extracted from the FOR-IN node.
    test("for(var a in b) foo()",
        "var a; for(a in b) foo()");

    // Verify vars are extracted from the FOR init before the label node.
    test("a:for(var a in b) foo()",
        "var a; a:for(a in b) foo()");
    // Verify vars are extracted from the FOR init before the labels node.
    test("a:b:for(var a in b) foo()",
        "var a; a:b:for(a in b) foo()");

    // Verify block are properly introduced for ifs.
    test("if (x) for(var a in b) foo()",
        "if (x) { var a; for(a in b) foo() }");
  }

  public void testForIn2() {
    setExpectParseWarningsThisTest();
    setAcceptedLanguage(LanguageMode.ECMASCRIPT5);
    // Verify vars are extracted from the FOR-IN node.
    test("for(var a = foo() in b) foo()",
        "var a = foo(); for(a in b) foo()");
  }

  public void testForOf() {
    // Verify nothing happens with simple for-of
    testSame("for (a of b) foo();");

    // Verify vars are extracted from the FOR-OF node.
    test("for (var a of b) foo()",
        "var a; for (a of b) foo()");

    // Verify vars are extracted from the FOR init before the label node.
    test("a:for (var a of b) foo()",
        "var a; a: for (a of b) foo()");
    // Verify vars are extracted from the FOR init before the labels node.
    test("a: b: for (var a of b) foo()",
        "var a; a: b: for (a of b) foo()");

    // Verify block are properly introduced for ifs.
    test("if (x) for (var a of b) foo()",
        "if (x) { var a; for (a of b) foo() }");
  }

  public void testWhile() {
    // Verify while loops are converted to FOR loops.
    test("while(c < b) foo()",
        "for(; c < b;) foo()");
  }

  public void testMoveFunctions1() {
    test("function f() { if (x) return; foo(); function foo() {} }",
        "function f() {function foo() {} if (x) return; foo(); }");
    test(
        LINE_JOINER.join(
            "function f() { ",
            "  function foo() {} ",
            "  if (x) return;",
            "  foo(); ",
            "  function bar() {} ",
            "}"),
        LINE_JOINER.join(
            "function f() {",
            "  function foo() {}",
            "  function bar() {}",
            "  if (x) return;",
            "  foo();",
            "}"));
  }

  public void testMoveFunctions2() {
    testSame("function f() { function foo() {} }");
    test("function f() { f(); a:function bar() {} }",
        "function f() { f(); a:{ var bar = function () {} }}");
    test("function f() { f(); {function bar() {}}}",
        "function f() { f(); {var bar = function () {}}}");
    test("function f() { f(); if (true) {function bar() {}}}",
        "function f() { f(); if (true) {var bar = function () {}}}");
  }

  private static String inFunction(String code) {
    return "(function(){" + code + "})";
  }

  private void testSameInFunction(String code) {
    testSame(inFunction(code));
  }

  private void testInFunction(String code, String expected) {
    test(inFunction(code), inFunction(expected));
  }

  public void testNormalizeFunctionDeclarations() {
    testSame("function f() {}");
    testSame("var f = function () {}");
    test("var f = function f() {}",
        "var f = function f$jscomp$1() {}");
    testSame("var f = function g() {}");
    test("a:function g() {}",
        "a:{ var g = function () {} }");
    test("{function g() {}}",
        "{var g = function () {}}");
    testSame("if (function g() {}) {}");
    test("if (true) {function g() {}}",
        "if (true) {var g = function () {}}");
    test("if (true) {} else {function g() {}}",
        "if (true) {} else {var g = function () {}}");
    testSame("switch (function g() {}) {}");
    test("switch (1) { case 1: function g() {}}",
        "switch (1) { case 1: var g = function () {}}");
    test("if (true) {function g() {} function h() {}}",
        "if (true) {var h = function() {}; var g = function () {}}");


    testSameInFunction("function f() {}");
    testInFunction("f(); a:function g() {}",
        "f(); a:{ var g = function () {} }");
    testInFunction("f(); {function g() {}}",
        "f(); {var g = function () {}}");
    testInFunction("f(); if (true) {function g() {}}",
        "f(); if (true) {var g = function () {}}");
    testInFunction("if (true) {} else {function g() {}}",
        "if (true) {} else {var g = function () {}}");
  }

  public void testMakeLocalNamesUnique() {
    // Verify global names are untouched.
    testSame("var a;");

    // Verify global names are untouched.
    testSame("a;");

    // Local names are made unique.
    test("var a;function foo(a){var b;a}",
        "var a;function foo(a$jscomp$1){var b;a$jscomp$1}");
    test("var a;function foo(){var b;a}function boo(){var b;a}",
        "var a;function foo(){var b;a}function boo(){var b$jscomp$1;a}");
    test("function foo(a){var b} function boo(a){var b}",
        "function foo(a){var b} function boo(a$jscomp$1){var b$jscomp$1}");

    // Verify function expressions are renamed.
    test("var a = function foo(){foo()};var b = function foo(){foo()};",
        "var a = function foo(){foo()};var b = function foo$jscomp$1(){foo$jscomp$1()};");

    // Verify catch exceptions names are made unique
    testSame("try { } catch(e) {e;}");
    test("try { } catch(e) {e;}; try { } catch(e) {e;}",
        "try { } catch(e) {e;}; try { } catch(e$jscomp$1) {e$jscomp$1;}");
    test("try { } catch(e) {e; try { } catch(e) {e;}};",
        "try { } catch(e) {e; try { } catch(e$jscomp$1) {e$jscomp$1;} }; ");

    // Verify the 1st global redefinition of extern definition is not removed.
    testSame("/** @suppress {duplicate} */ var window;");

    // Verify the 2nd global redefinition of extern definition is removed.
    test("/** @suppress {duplicate} */ var window; /** @suppress {duplicate} */ var window;",
        "/** @suppress {duplicate} */ var window;");

    // Verify local masking extern made unique.
    test("function f() {var window}",
        "function f() {var window$jscomp$1}");
  }

  public void testMakeParamNamesUnique() {
    test(
        "function f(x) { x; }\nfunction g(x) { x; }",
        "function f(x) { x; }\nfunction g(x$jscomp$1) { x$jscomp$1; }");

    test(
        "function f(x) { x; }\nfunction g(...x) { x; }",
        "function f(x) { x; }\nfunction g(...x$jscomp$1) { x$jscomp$1; }");

    test(
        "function f(x) { x; }\nfunction g({x: x}) { x; }",
        "function f(x) { x; }\nfunction g({x: x$jscomp$1}) { x$jscomp$1; }");

    test(
        "function f(x) { x; }\nfunction g({x}) { x; }",
        "function f(x) { x; }\nfunction g({x: x$jscomp$1}) { x$jscomp$1; }");

    test(
        "function f(x) { x; }\nfunction g({y: {x}}) { x; }",
        "function f(x) { x; }\nfunction g({y: {x: x$jscomp$1}}) { x$jscomp$1; }");
  }

  public void testNoRenameParamNames() {
    testSame("function f(x) { x; }");

    testSame("function f(...x) { x; }");

    testSame("function f({x: x}) { x; }");

    test("function f({x}) { x; }", "function f({x: x}) { x; }");

    test("function f({y: {x}}) { x; }", "function f({y: {x: x}}) { x; }");
  }

  public void testRemoveDuplicateVarDeclarations1() {
    test("function f() { var a; var a }",
        "function f() { var a; }");
    test("function f() { var a = 1; var a = 2 }",
        "function f() { var a = 1; a = 2 }");
    test("var a = 1; function f(){ var a = 2 }",
        "var a = 1; function f(){ var a$jscomp$1 = 2 }");
    test(
        "function f() { var a = 1; label1:var a = 2 }",
        "function f() { var a = 1; label1:{a = 2}}");
    test("function f() { var a = 1; label1:var a }", "function f() { var a = 1; label1:{} }");
    test("function f() { var a = 1; for(var a in b); }",
        "function f() { var a = 1; for(a in b); }");
  }

  public void testRemoveDuplicateVarDeclarations2() {
    test("var e = 1; function f(){ try {} catch (e) {} var e = 2 }",
        "var e = 1; function f(){ try {} catch (e$jscomp$2) {} var e$jscomp$1 = 2 }");
  }

  public void testRemoveDuplicateVarDeclarations3() {
    test("var f = 1; function f(){}",
        "f = 1; function f(){}");
    test("var f; function f(){}",
        "function f(){}");
    test("if (a) { var f = 1; } else { function f(){} }",
        "if (a) { var f = 1; } else { f = function (){} }");

    test("function f(){} var f = 1;",
        "function f(){} f = 1;");
    test("function f(){} var f;",
        "function f(){}");
    test("if (a) { function f(){} } else { var f = 1; }",
        "if (a) { var f = function (){} } else { f = 1; }");

    // TODO(johnlenz): Do we need to handle this differently for "third_party"
    // mode? Remove the previous function definitions?
    testSame("function f(){} function f(){}");
    test("if (a) { function f(){} } else { function f(){} }",
        "if (a) { var f = function (){} } else { f = function (){} }");
  }

  // It's important that we not remove this var completely. See
  // http://blickly.github.io/closure-compiler-issues/#290
  public void testRemoveDuplicateVarDeclarations4() {
    testSame("if (!Arguments) { /** @suppress {duplicate} */ var Arguments = {}; }");
  }

  // If there are multiple duplicates, it's okay to remove all but the first.
  public void testRemoveDuplicateVarDeclarations5() {
    test("var Arguments = {}; var Arguments = {};", "var Arguments = {}; Arguments = {};");
  }

  public void testRemoveVarDeclarationDuplicatesParam1() {
    test(
        "function f(x) { alert(x); var x = 0; alert(x); }",
        "function f(x) { alert(x);     x = 0; alert(x); }");
  }

  public void testRemoveVarDeclarationDuplicatesParam2() {
    test(
        "function f(x) { alert(x); var x; alert(x); }",
        "function f(x) { alert(x);        alert(x); }");
  }

  public void testRenamingConstants() {
    testSame("var ACONST = 4; var b = ACONST;");

    test("var a, ACONST = 4;var b = ACONST;",
        "var a; var ACONST = 4; var b = ACONST;");

    testSame("var ACONST; ACONST = 4; var b = ACONST;");

    testSame("var ACONST = new Foo(); var b = ACONST;");

    testSame("/** @const */ var aa; aa = 1;");
  }

  public void testSkipRenamingExterns() {
    test("var EXTERN; var ext; ext.FOO;", "var b = EXTERN; var c = ext.FOO",
        "var b = EXTERN; var c = ext.FOO");
  }

  public void testIssue166e() {
    test("var e = 2; try { throw 1 } catch(e) {}",
        "var e = 2; try { throw 1 } catch(e$jscomp$1) {}");
  }

  public void testIssue166f() {
    test(
        LINE_JOINER.join(
            "function a() {",
            "  var e = 2;",
            "  try { throw 1 } catch(e) {}",
            "}"),
        LINE_JOINER.join(
            "function a() {",
            "  var e = 2;",
            "  try { throw 1 } catch(e$jscomp$1) {}",
            "}"));
  }

  public void testIssue166g() {
    test(
        LINE_JOINER.join(
            "function a() {",
            "  try { throw 1 } catch(e) {}",
            "  var e = 2;",
            "}"),
        LINE_JOINER.join(
            "function a() {",
            "  try { throw 1 } catch(e$jscomp$1) {}",
            "  var e = 2;",
            "}"));
  }

  public void testLetsInSeparateBlocks() {
    test(
        LINE_JOINER.join(
            "if (x) {",
            "  let e;",
            "  alert(e);",
            "}",
            "if (y) {",
            "  let e;",
            "  alert(e);",
            "}"),
        LINE_JOINER.join(
            "if (x) {",
            "  let e;",
            "  alert(e);",
            "}",
            "if (y) {",
            "  let e$jscomp$1;",
            "  alert(e$jscomp$1);",
            "}"));
  }

  public void testCatchesInSeparateBlocks() {
    test(
        LINE_JOINER.join(
            "if (x) {",
            "  try {",
            "    throw 1;",
            "  } catch (e) {",
            "    alert(e);",
            "  }",
            "}",
            "if (y) {",
            "  try {",
            "    throw 2;",
            "  } catch (e) {",
            "    alert(e);",
            "  }",
            "}"),
        LINE_JOINER.join(
            "if (x) {",
            "  try {",
            "    throw 1;",
            "  } catch (e) {",
            "    alert(e);",
            "  }",
            "}",
            "if (y) {",
            "  try {",
            "    throw 2;",
            "  } catch (e$jscomp$1) {",
            "    alert(e$jscomp$1);",
            "  }",
            "}"));
  }

  public void testDeclInCatchBlock() {
    test(
        LINE_JOINER.join(
            "var x;",
            "try {",
            "} catch (e) {",
            "  let x;",
            "}"),
        LINE_JOINER.join(
            "var x;",
            "try {",
            "} catch (e) {",
            "  let x$jscomp$1",
            "}"));
  }

  public void testIssue() {
    allowExternsChanges();
    test("var a,b,c; var a,b", "a(), b()", "a(), b()");
  }

  public void testNormalizeSyntheticCode() {
    Compiler compiler = new Compiler();
    compiler.init(
        new ArrayList<SourceFile>(),
        new ArrayList<SourceFile>(), new CompilerOptions());
    String code = "function f(x) {} function g(x) {}";
    Node ast = compiler.parseSyntheticCode(code);
    Normalize.normalizeSyntheticCode(compiler, ast, "prefix_");
    assertEquals(
        "function f(x$jscomp$prefix_0){}function g(x$jscomp$prefix_1){}",
        compiler.toSource(ast));
  }

  public void testIsConstant() {
    testSame("var CONST = 3; var b = CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(2);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testIsConstantByDestructuring() {
    test(
        "var {CONST} = {CONST:3}; var b = CONST;",
        "var {CONST: CONST} = {CONST:3}; var b = CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(4);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testIsConstantByDestructuringWithDefault() {
    test("var {CONST = 3} = {}; var b = CONST;", "var {CONST: CONST = 3} = {}; var b = CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(3);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testPropertyIsConstant1() {
    testSame("var a = {}; a.CONST = 3; var b = a.CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(2);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testPropertyIsConstant2() {
    testSame("var a = {CONST: 3}; var b = a.CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(2);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testGetterPropertyIsConstant() {
    testSame("var a = { get CONST() {return 3} }; var b = a.CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(2);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testSetterPropertyIsConstant() {
    // Verifying that a SET is properly annotated.
    testSame("var a = { set CONST(b) {throw 'invalid'} }; var c = a.CONST;");
    Node n = getLastCompiler().getRoot();

    Set<Node> constantNodes = findNodesWithProperty(n, Node.IS_CONSTANT_NAME);
    assertThat(constantNodes).hasSize(2);
    for (Node hasProp : constantNodes) {
      assertEquals("CONST", hasProp.getString());
    }
  }

  public void testExposeSimple() {
    test("var x = {}; /** @expose */ x.y = 3; x.y = 5;",
        "var x = {}; /** @expose */ x['y'] = 3; x['y'] = 5;");
  }

  public void testExposeComplex() {
    test("var x = {/** @expose */ a: 1, b: 2}; x.a = 3; /** @expose */ x.b = 5;",
        "var x = {/** @expose */ 'a': 1, 'b': 2}; x['a'] = 3; /** @expose */ x['b'] = 5;");
  }

  public void testShadowFunctionName() {
    test(
        LINE_JOINER.join(
            "function f() {",
            "  var f = 'test';",
            "  console.log(f);",
            "}"),
        LINE_JOINER.join(
            "function f() {",
            "  var f$jscomp$1 = 'test';",
            "  console.log(f$jscomp$1);",
            "}"));
  }

  private Set<Node> findNodesWithProperty(Node root, final byte prop) {
    final Set<Node> set = new HashSet<>();

    NodeTraversal.traverseEs6(
        getLastCompiler(),
        root,
        new AbstractPostOrderCallback() {
          @Override
          public void visit(NodeTraversal t, Node node, Node parent) {
            if (node.getBooleanProp(prop)) {
              set.add(node);
            }
          }
        });
    return set;
  }

  public void testRenamingConstantProperties() throws Exception {
    // In order to detect that foo.BAR is a constant, we need collapse
    // properties to run first so that we can tell if the initial value is
    // non-null and immutable. The Normalize pass doesn't modify the code
    // in these examples, it just infers const-ness of some variables, so
    // we call enableNormalize to make the Normalize.VerifyConstants pass run.

    // TODO(johnlenz): fix this so it is just another test case.
    CompilerTestCase tester = new CompilerTestCase() {
      @Override
      protected int getNumRepetitions() {
        // The normalize pass is only run once.
        return 1;
      }

      @Override
      protected CompilerPass getProcessor(Compiler compiler) {
        return new CollapseProperties(compiler);
      }
    };

    tester.setUp();
    tester.enableNormalize();

    tester.test(
        "var a={}; a.ACONST = 4;var b = 1; b = a.ACONST;",
        "var a$ACONST = 4; var b = 1; b = a$ACONST;");

    tester.test(
        "var a={b:{}}; a.b.ACONST = 4;var b = 1; b = a.b.ACONST;",
        "var a$b$ACONST = 4;var b = 1; b = a$b$ACONST;");

    tester.test(
        "var a = {FOO: 1};var b = 1; b = a.FOO;",
        "var a$FOO = 1; var b = 1; b = a$FOO;");

    tester.testSame(
        "var EXTERN; var ext; ext.FOO;",
        "var b = EXTERN; var c = ext.FOO");

    tester.test(
        "var a={}; a.ACONST = 4; var b = 1; b = a.ACONST;",
        "var a$ACONST = 4; var b = 1; b = a$ACONST;");

    tester.test(
        "var a = {}; function foo() { var d = a.CONST; }; (function(){a.CONST=4})();",
        "var a$CONST;function foo(){var d = a$CONST;}; (function(){a$CONST = 4})();");

    tester.test(
        "var a = {}; a.ACONST = new Foo(); var b = 1; b = a.ACONST;",
        "var a$ACONST = new Foo(); var b = 1; b = a$ACONST;");

    tester.tearDown();
  }

  public void testFunctionBlock1() {
    test("() => 1;", "() => { return 1; }");
  }

  public void testFunctionBlock2() {
    test("var args = 1; var foo = () => args;",
        "var args = 1; var foo = () => { return args; }");
  }

  public void testArrowFunctionInFunction(){
    test(
        LINE_JOINER.join(
            "function foo() {",
            "  var x = () => 1;",
            "  return x();",
            "}"),
        LINE_JOINER.join(
            "function foo() {",
            "  var x = () => { return 1; };",
            "  return x();",
            "}"));
  }

  public void testES6ShorthandPropertySyntax01() {
    test("obj = {x, y};", "obj = {x: x, y: y}");
  }

  public void testES6ShorthandPropertySyntax02() {
    test("var foo = {x, y};", "var foo = {x: x, y: y}");
  }

  public void testES6ShorthandPropertySyntax03() {
    test(
        LINE_JOINER.join(
            "function foo(a, b, c) {",
            "  return {",
            "    a,",
            "    b,",
            "    c",
            "  };",
            "}"),
        LINE_JOINER.join(
            "function foo(a, b, c) {",
            "  return {",
            "    a: a,",
            "    b: b,",
            "    c: c",
            "  };",
            "}"));
  }

  public void testES6ShorthandPropertySyntax04() {
    test("var foo = {x};", "var foo = {x: x}");
  }

  public void testES6ShorthandPropertySyntax05() {
    test("var {a = 5} = obj;", "var {a: a = 5} = obj;");
  }

  public void testES6ShorthandPropertySyntax06() {
    test("var {a = 5, b = 3} = obj;", "var {a: a = 5, b: b = 3} = obj;");
  }

  public void testES6ShorthandPropertySyntax07() {
    test("var {a: a = 5, b = 3} = obj;", "var {a: a = 5, b: b = 3} = obj;");
  }

  public void testES6ShorthandPropertySyntax08() {
    test("var {a, b} = obj;", "var {a: a, b: b} = obj;");
  }

  public void testES6ShorthandPropertySyntax09() {
    test("({a = 5} = obj);", "({a: a = 5} = obj);");
  }

  public void testES6ShorthandPropertySyntax10() {
    testSame("function f(a = 5) {}");
  }

  public void testES6ShorthandPropertySyntax11() {
    testSame("[a = 5] = obj;");
  }

  public void testES6ShorthandPropertySyntax12() {
    testSame("({a: a = 5} = obj)");
  }

  public void testES6ShorthandPropertySyntax13() {
    testSame("({['a']: a = 5} = obj);");
  }

  public void testRewriteExportSpecShorthand1() {
    test("var a; export {a};", "var a$jscomp$1; export {a$jscomp$1 as a};");
  }

  public void testRewriteExportSpecShorthand2() {
    test("export {a, b as c, d};", "export {a as a, b as c, d as d};");
  }

  public void testSplitExportDeclarationWithVar() {
    test("export var a;",
        "var a$jscomp$1; export {a$jscomp$1 as a};");
    test("export var a = 4;",
        "var a$jscomp$1 = 4; export {a$jscomp$1 as a};");
    test("export var a, b;",
        LINE_JOINER.join(
            "var a$jscomp$1;",
            "var b$jscomp$1;",
            "export {a$jscomp$1 as a, b$jscomp$1 as b};"));

  }

  public void testSplitExportDeclarationWithShorthandProperty() {
    test("export var a = {b};",
            "var a$jscomp$1 = {b: b}; export {a$jscomp$1 as a};");
  }

  public void testSplitExportDeclarationWithDestructuring() {
    test("export var {} = {};", "var {} = {}; export {};");
    test(LINE_JOINER.join(
        "let obj = {a: 3, b: 2};",
        "export var {a, b: d, e: f = 2} = obj;"),
        LINE_JOINER.join(
            "let obj = {a: 3, b: 2};",
            "var {a: a, b: d, e: f = 2} = obj;",
            "export {a as a, d as d, f as f};"));
  }

  public void testSplitExportDeclarationWithLet() {
    test("export let a;", "let a; export {a as a};");
  }

  public void testSplitExportDeclarationWithConst() {
    test("export const a = 17;", "const a = 17; export {a as a};");
  }

  public void testSplitExportDeclarationOfFunction() {
    test("export function bar() {};",
        LINE_JOINER.join(
            "function bar$jscomp$1() {}",
            "export {bar$jscomp$1 as bar};"
        ));

    // Don't need to split declarations in default exports since they are either unnamed, or the
    // name is declared in the module scope only.
    testSame("export default function() {}");
    test("export default function foo() {}", "export default function foo$jscomp$1() {}");
  }

  public void testSplitExportDeclarationOfClass() {
    test("export class Foo {};", "class Foo {}; export {Foo as Foo};");
    testSame("export default class Bar {}");
    testSame("export default class {}");
  }
}