/*
 * Copyright 2006 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.javascript.jscomp.CollapseProperties.NAMESPACE_REDEFINED_WARNING;
import static com.google.javascript.jscomp.CollapseProperties.UNSAFE_NAMESPACE_WARNING;
import static com.google.javascript.jscomp.CollapseProperties.UNSAFE_THIS;

import com.google.common.collect.ImmutableMap;
import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
import com.google.javascript.jscomp.CompilerOptions.PropertyCollapseLevel;
import com.google.javascript.jscomp.deps.ModuleLoader.ResolutionMode;
import java.util.ArrayList;
import java.util.List;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * Tests {@link CollapseProperties}.
 *
 */

@RunWith(JUnit4.class)
public final class CollapsePropertiesTest extends CompilerTestCase {

  private static final String EXTERNS =
      "var window;\n"
      + "function alert(s) {}\n"
      + "function parseInt(s) {}\n"
      + "/** @constructor */ function String() {};\n"
      + "var arguments";

  private PropertyCollapseLevel propertyCollapseLevel = PropertyCollapseLevel.ALL;

  private boolean enableDependencyManagement = false;
  private List<ModuleIdentifier> entryPoints = null;

  public CollapsePropertiesTest() {
    super(EXTERNS);
  }

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

  @Override
  @Before
  public void setUp() throws Exception {
    super.setUp();
    enableNormalize();
    disableScriptFeatureValidation();
  }

  private void setupModuleExportsOnly() {
    this.setAcceptedLanguage(LanguageMode.ECMASCRIPT_2015);
    this.setLanguageOut(LanguageMode.ECMASCRIPT5);
    enableProcessCommonJsModules();
    enableTranspile();
    propertyCollapseLevel = PropertyCollapseLevel.MODULE_EXPORT;
  }

  @Override
  protected CompilerOptions getOptions() {
    CompilerOptions options = super.getOptions();

    if (this.enableDependencyManagement && this.entryPoints != null) {
      options.setDependencyOptions(DependencyOptions.pruneForEntryPoints(this.entryPoints));
    }

    return options;
  }

  @Test
  public void doNotCollapseAStaticPropertyUsedInAGetter() {
    test(
        lines(
            "class C {",
            "  /** @type {number} */",
            "  static get p() { return this.p_; }",
            "}",
            // declaration and initialization of private static field
            "/** @private {number} */",
            "C.p_ = 1;",
            // reference via getter
            "alert(C.p);",
            ""),
        lines(
            "class C {",
            "  /** @type {number} */",
            "  static get p() { return this.p_; }",
            "}",
            // TODO(b/130682799): C.p_ should not be collapsed
            "/** @private {number} */",
            "var C$p_ = 1;",
            "alert(C.p);",
            ""));
  }

  @Test
  public void doNotCollapseAStaticPropertyUsedInASetter() {
    test(
        lines(
            "class C {",
            "  /** @param {number} v */",
            "  static set p(v) { this.p_ = v; }",
            "}",
            // declaration and initialization of private static field
            "/** @private {number} */",
            "C.p_ = 0;",
            // changing private static field through setter property
            "C.p = 1;",
            "alert(C.p_);",
            ""),
        lines(
            "class C {",
            "  /** @param {number} v */",
            "  static set p(v) { this.p_ = v; }",
            "}",
            // TODO(b/130682799): C.p_ should not be collapsed
            "/** @private {number} */",
            "var C$p_ = 0;",
            "C.p = 1;",
            "alert(C$p_);",
            ""));
  }

  @Test
  public void doNotCollapseAStaticPropertyReadInAStaticMethod() {
    testWarning(
        lines(
            "class C {",
            "  /** @return {number} */",
            "  static getP() { return this.p_; }",
            "}",
            // declaration and initialization of private static field
            "/** @private {number} */",
            "C.p_ = 1;",
            // reference via method
            "alert(C.getP());",
            ""),
        lines(
            "class C {",
            "  /** @return {number} */",
            "  static getP() { return this.p_; }",
            "}",
            // declaration and initialization of private static field
            "/** @private {number} */",
            "C.p_ = 1;",
            // reference via method
            "alert(C.getP());",
            ""),
        // TODO(b/117437011): should recognize type of `this` in a static method
        UNSAFE_THIS);
  }

  @Test
  public void doNotCollapseAStaticPropertyAssignedInAStaticMethod() {
    testWarning(
        lines(
            "class C {",
            "  /** @param {number} v */",
            "  static setP(v) { this.p_ = v; }",
            "}",
            // declaration and initialization of private static field
            "/** @private {number} */",
            "C.p_ = 0;",
            // changing private static field through method
            "C.setP(1);",
            "alert(C.p_);",
            ""),
        lines(
            "class C {",
            "  /** @param {number} v */",
            "  static setP(v) { this.p_ = v; }",
            "}",
            // declaration and initialization of private static field
            "/** @private {number} */",
            "C.p_ = 0;",
            // changing private static field through method
            "C.setP(1);",
            "alert(C.p_);",
            ""),
        // TODO(b/117437011): should recognize type of `this` in a static method
        UNSAFE_THIS);
  }

  @Test
  public void doNotCollapseAPropertyReadByAnObjectLiteralMethod() {
    test(
        lines(
            "const obj = {",
            "  /** @private {number} */",
            "  p_: 0,",
            "  /**",
            "   * @this {{p_: number}}",
            "   * @return {number}",
            "   */",
            "  getP() { return this.p_; }",
            "};",
            "alert(obj.getP());",
            ""),
        lines(
            // TODO(b/130829946): Should not collapse obj.p_ and obj.getP
            "var obj$p_ = 0;",
            "var obj$getP = function() { return this.p_; };",
            "alert(obj$getP());",
            ""));
  }

  @Test
  public void doNotCollapseAPropertyAssignedInAnObjectLiteralMethod() {
    test(
        lines(
            "const obj = {",
            "  /** @private {number} */",
            "  p_: 0,",
            "  /**",
            "   * @this {{p_: number}}",
            "   * @param {number} v",
            "   */",
            "  setP(v) { this.p_ = v; }",
            "}",
            "obj.setP(1);",
            "alert(obj.p_);",
            ""),
        lines(
            // TODO(b/130829946): Should not collapse obj.p_ and obj.getP
            "var obj$p_ = 0;",
            "var obj$setP = function(v) { this.p_ = v; };",
            "obj$setP(1);",
            "alert(obj$p_);",
            ""));
  }

  @Test
  public void doNotCollapseAPropertyUsedInAnObjectLiteralGetter() {
    test(
        lines(
            "const obj = {",
            "  /** @private {number} */",
            "  p_: 0,",
            "  /** @type {number} */",
            "  get p() { return this.p_; }",
            "}",
            "alert(obj.p);",
            ""),
        lines(
            // TODO(b/130829946): Should not collapse obj.p_
            "var obj$p_ = 0;",
            "const obj = {",
            "  /** @type {number} */",
            "  get p() { return this.p_; }",
            "}",
            "alert(obj.p);",
            ""));
  }

  @Test
  public void doNotCollapseAPropertyUsedInAnObjectLiteralSetter() {
    test(
        lines(
            "const obj = {",
            "  /** @private {number} */",
            "  p_: 0,",
            "  /** @param {number} v */",
            "  set p(v) { this.p_ = v; }",
            "}",
            "obj.p = 1;",
            "alert(obj.p_);",
            ""),
        lines(
            // TODO(b/130829946): Should not collapse obj.p_
            "var obj$p_ = 0;",
            "const obj = {",
            "  /** @param {number} v */",
            "  set p(v) { this.p_ = v; }",
            "}",
            "obj.p = 1;",
            "alert(obj$p_);",
            ""));
  }

  @Test
  public void testMultiLevelCollapse() {
    test("var a = {}; a.b = {}; a.b.c = {}; var d = 1; d = a.b.c;",
         "var a$b$c = {}; var d = 1; d = a$b$c;");

    test(
        "var a = {}; a.b = {}; /** @nocollapse */ a.b.c = {}; var d = 1; d = a.b.c;",
        "var a$b = {}; /** @nocollapse */ a$b.c = {}; var d = 1; d = a$b.c;");
  }

  @Test
  public void testDecrement() {
    test("var a = {}; a.b = 5; a.b--; a.b = 5",
         "var a$b = 5; a$b--; a$b = 5");
  }

  @Test
  public void testIncrement() {
    test("var a = {}; a.b = 5; a.b++; a.b = 5",
         "var a$b = 5; a$b++; a$b = 5");
  }

  @Test
  public void testObjLitDeclarationWithGet1() {
    testSame("var a = {get b(){}};");
  }

  @Test
  public void testObjLitDeclarationWithGet3() {
    test("var a = {b: {get c() { return 3; }}};",
         "var a$b = {get c() { return 3; }};");
  }

  @Test
  public void testObjLitDeclarationWithSet1() {
    testSame("var a = {set b(a){}};");
  }

  @Test
  public void testObjLitDeclarationWithSet3() {
    test("var a = {b: {set c(d) {}}};",
         "var a$b = {set c(d) {}};");
  }

  @Test
  public void testObjLitDeclarationWithUsedSetter() {
    testSame("var a = {set b(c) {}}; a.b = 4;");
  }

  @Test
  public void testObjLitDeclarationDoesntCollapsePropertiesOnGetter() {
    testSame(
        lines(
            "var a = {",
            "  get b() { return class {}; },",
            "  set b(c) {}",
            "};",
            "a.b = class {};",
            "a.b.c = 4;"));
  }

  @Test
  public void testObjLitDeclarationWithGetAndSet1() {
    test("var a = {b: {get c() { return 3; },set c(d) {}}};",
         "var a$b = {get c() { return 3; },set c(d) {}};");
  }

  @Test
  public void testObjLitAssignmentDepth1() {
    test("var a = {b: {}, c: {}}; var d = 1; var e = 1; d = a.b; e = a.c",
         "var a$b = {}; var a$c = {}; var d = 1; var e = 1; d = a$b; e = a$c");

    test("var a = {b: {}, /** @nocollapse */ c: {}}; var d = 1; d = a.b; var e = 1; e = a.c",
        "var a$b = {}; var a = { /** @nocollapse */c: {}}; var d = 1; d = a$b; var e = 1; e = a.c");
  }

  @Test
  public void testObjLitAssignmentDepth2() {
    test("var a = {}; a.b = {c: {}, d: {}}; var e = 1; e = a.b.c; var f = 1; f = a.b.d",
         "var a$b$c = {}; var a$b$d = {}; var e = 1; e = a$b$c; var f = 1; f = a$b$d;");

    test("var a = {}; a.b = {c: {}, /** @nocollapse */ d: {}}; var e = 1; e = a.b.c;"
        + "var f = 1; f = a.b.d",
        "var a$b$c = {}; var a$b = { /** @nocollapse */ d: {}}; var e = 1; e = a$b$c;"
        + "var f = 1; f = a$b.d;");
  }

  @Test
  public void testGlobalObjectDeclaredToPreserveItsPreviousValue1() {
    test("var a = a ? a : {}; a.c = 1;",
         "var a = a ? a : {}; var a$c = 1;");

    test("var a = a ? a : {}; /** @nocollapse */ a.c = 1;",
        "var a = a ? a : {}; /** @nocollapse */ a.c = 1;");
  }

  @Test
  public void testGlobalObjectDeclaredToPreserveItsPreviousValue2() {
    test("var a = a || {}; a.c = 1;",
         "var a = a || {}; var a$c = 1;");

    testSame("var a = a || {}; /** @nocollapse */ a.c = 1;");
 }

  @Test
  public void testGlobalObjectDeclaredToPreserveItsPreviousValue3() {
    test("var a = a || {get b() {}}; a.c = 1;",
         "var a = a || {get b() {}}; var a$c = 1;");

    testSame("var a = a || {get b() {}}; /** @nocollapse */ a.c = 1;");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth1_1() {
    test("var a = {b: 0}; a.c = 1; if (a) x();",
         "var a$b = 0; var a = {}; var a$c = 1; if (a) x();");

    test("var a = {/** @nocollapse */ b: 0}; a.c = 1; if (a) x();",
        "var a = {/** @nocollapse */ b: 0}; var a$c = 1; if (a) x();");

    test("var a = {b: 0}; /** @nocollapse */ a.c = 1; if (a) x();",
        "var a$b = 0; var a = {}; /** @nocollapse */ a.c = 1; if (a) x();");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth1_2() {
    test("var a = {b: 0}; a.c = 1; if (!(a && a.c)) x();",
         "var a$b = 0; var a = {}; var a$c = 1; if (!(a && a$c)) x();");

    test("var a = {/** @nocollapse */ b: 0}; a.c = 1; if (!(a && a.c)) x();",
        "var a = {/** @nocollapse */ b: 0}; var a$c = 1; if (!(a && a$c)) x();");

    test("var a = {b: 0}; /** @nocollapse */ a.c = 1; if (!(a && a.c)) x();",
        "var a$b = 0; var a = {}; /** @nocollapse */ a.c = 1; if (!(a && a.c)) x();");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth1_3() {
    test("var a = {b: 0}; a.c = 1; while (a || a.c) x();",
         "var a$b = 0; var a = {}; var a$c = 1; while (a || a$c) x();");

    test("var a = {/** @nocollapse */ b: 0}; a.c = 1; while (a || a.c) x();",
        "var a = {/** @nocollapse */ b: 0}; var a$c = 1; while (a || a$c) x();");

    test("var a = {b: 0}; /** @nocollapse */ a.c = 1; while (a || a.c) x();",
        "var a$b = 0; var a = {}; /** @nocollapse */ a.c = 1; while (a || a.c) x();");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth1_4() {
    testSame("var a = {}; a.c = 1; var d = a || {}; a.c;");

    testSame("var a = {}; /** @nocollapse */ a.c = 1; var d = a || {}; a.c;");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth1_5() {
    testSame("var a = {}; a.c = 1; var d = a.c || a; a.c;");

    testSame("var a = {}; /** @nocollapse */ a.c = 1; var d = a.c || a; a.c;");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth1_6() {
    test("var a = {b: 0}; a.c = 1; var d = !(a.c || a); a.c;",
         "var a$b = 0; var a = {}; var a$c = 1; var d = !(a$c || a); a$c;");

    test("var a = {/** @nocollapse */ b: 0}; a.c = 1; var d = !(a.c || a); a.c;",
        "var a = {/** @nocollapse */ b: 0}; var a$c = 1; var d = !(a$c || a); a$c;");

    test("var a = {b: 0}; /** @nocollapse */ a.c = 1; var d = !(a.c || a); a.c;",
        "var a$b = 0; var a = {}; /** @nocollapse */ a.c = 1; var d = !(a.c || a); a.c;");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth2() {
    test("var a = {b: {}}; a.b.c = 1; if (a.b) x(a.b.c);",
         "var a$b = {}; var a$b$c = 1; if (a$b) x(a$b$c);");

    testSame("var a = {/** @nocollapse */ b: {}}; a.b.c = 1; if (a.b) x(a.b.c);");

    test("var a = {b: {}}; /** @nocollapse */ a.b.c = 1; if (a.b) x(a.b.c);",
        "var a$b = {}; /** @nocollapse */ a$b.c = 1; if (a$b) x(a$b.c);");
  }

  @Test
  public void testGlobalObjectNameInBooleanExpressionDepth3() {
    // TODO(user): Make CollapseProperties even more aggressive so that
    // a$b.z gets collapsed. Right now, it doesn't get collapsed because the
    // expression (a.b && a.b.c) could return a.b. But since it returns a.b iff
    // a.b *is* safely collapsible, the Boolean logic should be smart enough to
    // only consider the right side of the && as aliasing.
    test(
        "var a = {}; a.b = {}; /** @constructor */ a.b.c = function(){};"
            + " a.b.z = 1; var d = a.b && a.b.c;",
        "var a$b = {}; /** @constructor */ var a$b$c = function(){};"
            + " a$b.z = 1; var d = a$b && a$b$c;",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testGlobalFunctionNameInBooleanExpressionDepth1() {
    test("function a() {} a.c = 1; if (a) x(a.c);",
         "function a() {} var a$c = 1; if (a) x(a$c);");

    test("function a() {} /** @nocollapse */ a.c = 1; if (a) x(a.c);",
        "function a() {} /** @nocollapse */ a.c = 1; if (a) x(a.c);");
  }

  @Test
  public void testGlobalFunctionNameInBooleanExpressionDepth2() {
    test("var a = {b: function(){}}; a.b.c = 1; if (a.b) x(a.b.c);",
         "var a$b = function(){}; var a$b$c = 1; if (a$b) x(a$b$c);");

    testSame("var a = {/** @nocollapse */ b: function(){}}; a.b.c = 1; "
        + "if (a.b) x(a.b.c);");

    test("var a = {b: function(){}}; /** @nocollapse */ a.b.c = 1; "
        + "if (a.b) x(a.b.c);",
        "var a$b = function(){}; /** @nocollapse */ a$b.c = 1; if (a$b) x(a$b.c);");
  }

  @Test
  public void testDontCollapseObjectLiteralVarDeclarationInsideLoop() {
    // See https://github.com/google/closure-compiler/issues/3050
    // Another solution to the issue would be to explicitly initialize obj.val to undefined at the
    // start of the loop, but that requires some more refactoring of CollapseProperties.
    testSame(
        lines(
            "for (var i = 0; i < 2; i++) {",
            "  var obj = {};",
            "  if (i == 0) {",
            "    obj.val = 1;",
            "  }",
            "  alert(obj.val);",
            "}"));
  }

  @Test
  public void testDontCollapseObjectLiteralPropertyDeclarationInsideLoop() {
    // we can collapse `obj.x` but not `obj.x.val`
    test(
        lines(
            "var obj = {};",
            "for (var i = 0; i < 2; i++) {",
            "  obj.x = {};",
            "  if (i == 0) {",
            "    obj.x.val = 1;",
            "  }",
            "  alert(obj.x.val);",
            "}"),
        lines(
            "for (var i = 0; i < 2; i++) {",
            "  var obj$x = {};",
            "  if (i == 0) {",
            "    obj$x.val = 1;",
            "  }",
            "  alert(obj$x.val);",
            "}"));
  }

  @Test
  public void testDontCollapseConstructorDeclarationInsideLoop() {
    testSame(
        lines(
            "for (var i = 0; i < 2; i++) {",
            "  /** @constructor */",
            "  var Foo = function () {}",
            "  if (i == 0) {",
            "    Foo.val = 1;",
            "  }",
            "  alert(Foo.val);",
            "}"));
  }

  @Test
  public void testDoCollapsePropertiesDeclaredInsideLoop() {
    // It's okay that this property is declared inside a loop as long as the object it's on is not.
    test(
        lines(
            "var obj = {};",
            "for (var i = 0; i < 2; i++) {",
            "  if (i == 0) {",
            "    obj.val = 1;",
            "  }",
            "  alert(obj.val);",
            "}"),
        lines(
            "for (var i = 0; i < 2; i++) {",
            "  if (i == 0) {",
            "    var obj$val = 1;",
            "  }",
            "  alert(obj$val);",
            "}"));
  }

  @Test
  public void testAliasCreatedForObjectDepth1_2() {
    testSame("var a = {b: 0}; f(a); a.b;");
  }

  @Test
  public void testAliasCreatedForObjectDepth1_3() {
    testSame("var a = {b: 0}; new f(a); a.b;");
  }

  @Test
  public void testAliasCreatedForObjectDepth2_1() {
    test("var a = {}; a.b = {c: 0}; var d = 1; d = a.b; a.b.c == d.c;",
         "var a$b = {c: 0}; var d = 1; d = a$b; a$b.c == d.c;");

    test("var a = {}; /** @nocollapse */ a.b = {c: 0}; var d = 1; d = a.b; "
        + "a.b.c == d.c;",
        "var a = {}; /** @nocollapse */ a.b = {c: 0}; var d = 1; d = a.b; a.b.c == d.c;");
  }

  @Test
  public void testAliasCreatedForObjectDepth2_2() {
    test("var a = {}; a.b = {c: 0}; for (var p in a.b) { e(a.b[p]); }",
         "var a$b = {c: 0}; for (var p in a$b) { e(a$b[p]); }");
  }

  @Test
  public void testEnumDepth1() {
    test("/** @enum */ var a = {b: 0, c: 1};",
         "var a$b = 0; var a$c = 1;");

    test(
        "/** @enum */ var a = { /** @nocollapse */ b: 0, c: 1};",
        "var a$c = 1; /** @enum */ var a = { /** @nocollapse */ b: 0};");
  }

  @Test
  public void testEnumDepth2() {
    test("var a = {}; /** @enum */ a.b = {c: 0, d: 1};",
        "var a$b$c = 0; var a$b$d = 1;");

    testSame("var a = {}; /** @nocollapse @enum */ a.b = {c: 0, d: 1};");
  }

  @Test
  public void testAliasCreatedForEnumDepth1_1() {
    // An enum's values are always collapsed, even if the enum object is
    // referenced in a such a way that an alias is created for it.
    // Unless an enum property has @nocollapse
    test("/** @enum */ var a = {b: 0}; var c = 1; c = a; c.b = 1; a.b != c.b;",
         "var a$b = 0; /** @enum */ var a = {b: a$b}; var c = 1; c = a; c.b = 1; a$b != c.b;");

    test("/** @enum */ var a = { /** @nocollapse */ b: 0}; var c = 1; c = a; c.b = 1; a.b == c.b;",
        "/** @enum */ var a = { /** @nocollapse */ b: 0}; var c = 1; c = a; c.b = 1; a.b == c.b;");
  }

  @Test
  public void testAliasCreatedForEnumDepth1_2() {
    test("/** @enum */ var a = {b: 0}; f(a); a.b;",
         "var a$b = 0; /** @enum */ var a = {b: a$b}; f(a); a$b;");
  }

  @Test
  public void testAliasCreatedForEnumDepth1_3() {
    test("/** @enum */ var a = {b: 0}; new f(a); a.b;",
         "var a$b = 0; /** @enum */ var a = {b: a$b}; new f(a); a$b;");
  }

  @Test
  public void testAliasCreatedForEnumDepth1_4() {
    test("/** @enum */ var a = {b: 0}; for (var p in a) { f(a[p]); }",
         "var a$b = 0; /** @enum */ var a = {b: a$b}; for (var p in a) { f(a[p]); }");
  }

  @Test
  public void testAliasCreatedForEnumDepth2_1() {
    test("var a = {}; /** @enum */ a.b = {c: 0};"
         + "var d = 1; d = a.b; d.c = 1; a.b.c != d.c;",
         "var a$b$c = 0; /** @enum */ var a$b = {c: a$b$c};"
         + "var d = 1; d = a$b; d.c = 1; a$b$c != d.c;");

    testSame("var a = {}; /** @nocollapse @enum */ a.b = {c: 0};"
        + "var d = 1; d = a.b; d.c = 1; a.b.c == d.c;");

    test("var a = {}; /** @enum */ a.b = {/** @nocollapse */ c: 0};"
        + "var d = 1; d = a.b; d.c = 1; a.b.c == d.c;",
        "/** @enum */ var a$b = { /** @nocollapse */ c: 0};"
        + "var d = 1; d = a$b; d.c = 1; a$b.c == d.c;");
  }

  @Test
  public void testAliasCreatedForEnumDepth2_2() {
    test("var a = {}; /** @enum */ a.b = {c: 0};"
         + "for (var p in a.b) { f(a.b[p]); }",
         "var a$b$c = 0; /** @enum */ var a$b = {c: a$b$c};"
         + "for (var p in a$b) { f(a$b[p]); }");
  }

  @Test
  public void testAliasCreatedForEnumDepth2_3() {
    test(
        "var a = {}; var d = 1; d = a; /** @enum */ a.b = {c: 0};"
            + "for (var p in a.b) { f(a.b[p]); }",
        "var a = {}; var d = 1; d = a; var a$b$c = 0; /** @enum */ var a$b = {c: a$b$c};"
            + "for (var p in a$b) { f(a$b[p]); }",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasCreatedForEnumOfObjects() {
    test("var a = {}; /** @enum {Object} */ a.b = {c: {d: 1}}; a.b.c; searchEnum(a.b);",
         "var a$b$c = {d: 1}; /** @enum {Object} */ var a$b = {c: a$b$c}; a$b$c; searchEnum(a$b)");
  }

  @Test
  public void testAliasCreatedForEnumOfObjects2() {
    test("var a = {}; "
         + "/** @enum {Object} */ a.b = {c: {d: 1}}; a.b.c.d;"
         + "searchEnum(a.b);",
         "var a$b$c = {d: 1}; /** @enum {Object} */ var a$b = {c: a$b$c}; a$b$c.d; "
         + "searchEnum(a$b)");
  }

  @Test
  public void testAliasCreatedForPropertyOfEnumOfObjects() {
    test("var a = {}; "
         + "/** @enum {Object} */ a.b = {c: {d: 1}}; a.b.c;"
         + "searchEnum(a.b.c);",
         "var a$b$c = {d: 1}; a$b$c; searchEnum(a$b$c);");
  }

  @Test
  public void testAliasCreatedForPropertyOfEnumOfObjects2() {
    test("var a = {}; "
         + "/** @enum {Object} */ a.b = {c: {d: 1}}; a.b.c.d;"
         + "searchEnum(a.b.c);",
         "var a$b$c = {d: 1}; a$b$c.d; searchEnum(a$b$c);");
  }

  @Test
  public void testMisusedEnumTag() {
    testSame("var a = {}; var d = 1; d = a; a.b = function() {}; /** @enum */ a.b.c = 0; a.b.c;");
  }

  @Test
  public void testAliasCreatedForFunctionDepth1_1() {
    testSame("var a = function(){}; a.b = 1; var c = 1; c = a; c.b = 2; a.b != c.b;");
  }

  @Test
  public void testAliasCreatedForFunctionDepth1_2() {
    testSame("var a = function(){}; a.b = 1; f(a); a.b;");
  }

  @Test
  public void testAliasCreatedForCtorDepth1_2() {
    test("/** @constructor */ var a = function(){}; a.b = 1; f(a); a.b;",
         "/** @constructor */ var a = function(){}; var a$b = 1; f(a); a$b;");

    testSame("/** @constructor */ var a = function(){}; /** @nocollapse */ a.b = 1; f(a); a.b;");
  }

  @Test
  public void testAliasCreatedForFunctionDepth1_3() {
    testSame("var a = function(){}; a.b = 1; new f(a); a.b;");
  }

  @Test
  public void testAliasCreatedForCtorDepth1_3() {
    test("/** @constructor */ var a = function(){}; a.b = 1; new f(a); a.b;",
         "/** @constructor */ var a = function(){}; var a$b = 1; new f(a); a$b;");

    testSame("/** @constructor */ var a = function(){};"
            + "/** @nocollapse */ a.b = 1; new f(a); a.b;");
  }

  @Test
  public void testAliasCreatedForClassDepth1_2() {
    test(
        "var a = {}; /** @constructor */ a.b = function(){}; f(a); a.b;",
        "var a = {}; /** @constructor */ var a$b = function(){}; f(a); a$b;",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasCreatedForClassDepth1_3() {
    test(
        "var a = {}; /** @constructor */ a.b = function(){}; new f(a); a.b;",
        "var a = {}; /** @constructor */ var a$b = function(){}; new f(a); a$b;",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasCreatedForClassDepth2_1() {
    test(
        lines(
            "var a = {};",
            "a.b = {};",
            "/** @constructor */",
            "a.b.c = function(){};",
            "var d = 1;",
            "d = a.b;",
            "a.b.c != d.c;"),
        lines(
            "var a$b = {}; ",
            "/** @constructor */",
            "var a$b$c = function(){};",
            "var d = 1;",
            "d = a$b;",
            "a$b$c != d.c;"),
        warning(UNSAFE_NAMESPACE_WARNING));

    test(
        lines(
            "var a = {};",
            "a.b = {};",
            " /** @constructor @nocollapse */",
            " a.b.c = function(){}; ",
            "var d = 1;",
            " d = a.b; ",
            "a.b.c == d.c;"),
        lines(
            "var a$b = {};",
            "/** @constructor @nocollapse */",
            "a$b.c = function(){};",
            "var d = 1; ",
            "d = a$b;",
            "a$b.c == d.c;"),
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasCreatedForClassDepth2_2() {
    test(
        "var a = {}; a.b = {}; /** @constructor */ a.b.c = function(){}; f(a.b); a.b.c;",
        "var a$b = {}; /** @constructor */ var a$b$c = function(){}; f(a$b); a$b$c;",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasCreatedForClassDepth2_3() {
    test(
        "var a = {}; a.b = {}; /** @constructor */ a.b.c = function(){}; new f(a.b); a.b.c;",
        "var a$b = {}; /** @constructor */ var a$b$c = function(){}; new f(a$b); a$b$c;",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasCreatedForClassProperty() {
    test(
        "var a = {}; /** @constructor */ a.b = function(){}; a.b.c = {d:3}; new f(a.b.c); a.b.c.d;",
        "/** @constructor */ var a$b = function(){}; var a$b$c = {d:3}; new f(a$b$c); a$b$c.d;");

    testSame("var a = {}; /** @constructor @nocollapse */ a.b = function(){};"
        + "a.b.c = {d: 3}; new f(a.b.c); a.b.c.d;");

    test(
        lines(
            "var a = {};",
            "/** @constructor */",
            "a.b = function(){};",
            "/** @nocollapse */",
            " a.b.c = {d: 3};",
            " new f(a.b.c);",
            " a.b.c.d;"),
        lines(
            "/** @constructor */",
            " var a$b = function(){};",
            " /** @nocollapse */",
            " a$b.c = {d:3};",
            " new f(a$b.c); ",
            "a$b.c.d;"));
  }

  @Test
  public void testNestedObjLit() {
    test("var a = {}; a.b = {f: 0, c: {d: 1}}; var e = 1; e = a.b.c.d",
        "var a$b$f = 0; var a$b$c$d = 1; var e = 1; e = a$b$c$d;");

    test("var a = {}; a.b = {f: 0, /** @nocollapse */ c: {d: 1}}; var e = 1; e = a.b.c.d",
        "var a$b$f = 0; var a$b ={ /** @nocollapse */ c: { d: 1 }}; var e = 1; e = a$b.c.d;");

    test("var a = {}; a.b = {f: 0, c: {/** @nocollapse */ d: 1}}; var e = 1; e = a.b.c.d",
        "var a$b$f = 0; var a$b$c = { /** @nocollapse */ d: 1}; var e = 1; e = a$b$c.d;");
  }

  @Test
  public void testPropGetInsideAnObjLit() {
    test("var x = {}; x.y = 1; var a = {}; a.b = {c: x.y}",
         "var x$y = 1; var a$b$c = x$y;");

    test(
        "var x = {}; /** @nocollapse */ x.y = 1; var a = {}; a.b = {c: x.y}",
        "var x = {}; /** @nocollapse */ x.y = 1; var a$b$c = x.y;");

    test(
        "var x = {}; x.y = 1; var a = {}; a.b = { /** @nocollapse */ c: x.y}",
        "var x$y = 1; var a$b = { /** @nocollapse */ c: x$y};");

    testSame("var x = {}; /** @nocollapse */ x.y = 1; var a = {};"
        + "/** @nocollapse */ a.b = {c: x.y}");
  }

  @Test
  public void testObjLitWithQuotedKeyThatDoesNotGetRead() {
    test("var a = {}; a.b = {c: 0, 'd': 1}; var e = 1; e = a.b.c;",
         "var a$b$c = 0; var a$b$d = 1; var e = 1; e = a$b$c;");

    test(
        "var a = {}; a.b = {c: 0, /** @nocollapse */ 'd': 1}; var e = 1; e = a.b.c;",
        "var a$b$c = 0; var a$b = {/** @nocollapse */ 'd': 1}; var e = 1; e = a$b$c;");
  }

  @Test
  public void testObjLitWithQuotedKeyThatGetsRead() {
    test("var a = {}; a.b = {c: 0, 'd': 1}; var e = a.b['d'];",
         "var a$b = {c: 0, 'd': 1}; var e = a$b['d'];");

    test(
        "var a = {}; a.b = {c: 0, /** @nocollapse */ 'd': 1}; var e = a.b['d'];",
        "var a$b = {c: 0, /** @nocollapse */ 'd': 1}; var e = a$b['d'];");
  }

  @Test
  public void testObjLitWithQuotedKeyThatDoesNotGetReadComputed() {
    //quoted/computed does not get read
    test(
        "var a = {}; a.b = {c: 0, ['d']: 1}; var e = 1; e = a.b.c;",
        //"var a = {}; a.b = {c: 0, ['d']: 1}; var e = 1; e = a.b.c;"
        "var a$b$c = 0; var e = 1; e = a$b$c"); //incorrect

    // quoted/computed gets read
    test(
        "var a = {}; a.b = {c: 0, ['d']: 1}; var e = a.b['d'];",
        "var a$b = {c: 0, ['d']: 1}; var e = a$b['d'];");

    // key collision
    test(
        "var a = {}; a.b = {c: 0, ['c']: 1}; var e = a.b.c;",
        //"var a$b = {c: 0, ['c']: 1}; var e = a$b.c;");
        "var a$b$c = 0; var e = a$b$c;"); //incorrect
  }

  @Test
  public void testFunctionWithQuotedPropertyThatDoesNotGetRead() {
    test("var a = {}; a.b = function() {}; a.b['d'] = 1;",
         "var a$b = function() {}; a$b['d'] = 1;");

    test("var a = {}; /** @nocollapse */ a.b = function() {}; a.b['d'] = 1;",
        "var a = {}; /** @nocollapse */ a.b = function() {}; a.b['d'] = 1;");

    test("var a = {}; a.b = function() {}; /** @nocollapse */ a.b['d'] = 1;",
        "var a$b = function() {}; /** @nocollapse */ a$b['d'] = 1;");
  }

  @Test
  public void testFunctionWithQuotedPropertyThatGetsRead() {
    test("var a = {}; a.b = function() {}; a.b['d'] = 1; f(a.b['d']);",
         "var a$b = function() {}; a$b['d'] = 1; f(a$b['d']);");

    testSame("var a = {}; /** @nocollapse */ a.b = function() {};"
        + "a.b['d'] = 1; f(a.b['d']);");

    test("var a = {}; a.b = function() {}; /** @nocollapse */ a.b['d'] = 1; f(a.b['d']);",
        "var a$b = function() {}; /** @nocollapse */ a$b['d'] = 1; f(a$b['d']);");
  }

  @Test
  public void testObjLitAssignedToMultipleNames1() {
    // An object literal that's assigned to multiple names isn't collapsed.
    testSame("var a = b = {c: 0, d: 1}; var e = a.c; var f = b.d;");

    testSame("var a = b = {c: 0, /** @nocollapse */ d: 1}; var e = a.c;"
        + "var f = b.d;");
  }

  @Test
  public void testObjLitAssignedToMultipleNames2() {
    testSame("a = b = {c: 0, d: 1}; var e = a.c; var f = b.d;");
  }

  @Test
  public void testObjLitRedefinedInGlobalScope() {
    testSame("a = {b: 0}; a = {c: 1}; var d = a.b; var e = a.c;");
  }

  @Test
  public void testObjLitRedefinedInLocalScope() {
    test("var a = {}; a.b = {c: 0}; function d() { a.b = {c: 1}; } e(a.b.c);",
         "var a$b = {c: 0}; function d() { a$b = {c: 1}; } e(a$b.c);");

    testSame("var a = {};/** @nocollapse */ a.b = {c: 0}; function d() { a.b = {c: 1};} e(a.b.c);");

    // redefinition with @nocollapse
    test("var a = {}; a.b = {c: 0}; "
        + "function d() { a.b = {/** @nocollapse */ c: 1}; } e(a.b.c);",
        "var a$b = {c: 0}; function d() { a$b = {/** @nocollapse */ c: 1}; } e(a$b.c);");
  }

  @Test
  public void testObjLitAssignedInTernaryExpression1() {
    testSame("a = x ? {b: 0} : d; var c = a.b;");
  }

  @Test
  public void testObjLitAssignedInTernaryExpression2() {
    testSame("a = x ? {b: 0} : {b: 1}; var c = a.b;");
  }

  @Test
  public void testGlobalVarSetToObjLitConditionally1() {
    testSame("var a; if (x) a = {b: 0}; var c = x ? a.b : 0;");
  }

  @Test
  public void testGlobalVarSetToObjLitConditionally1b() {
    test("if (x) var a = {b: 0}; var c = x ? a.b : 0;",
         "if (x) var a$b = 0; var c = x ? a$b : 0;");

    testSame("if (x) var a = { /** @nocollapse */ b: 0}; var c = x ? a.b : 0;");
  }

  @Test
  public void testGlobalVarSetToObjLitConditionally2() {
    test("if (x) var a = {b: 0}; var c = 1; c = a.b; var d = a.c;",
         "if (x){ var a$b = 0; var a = {}; }var c = 1; c = a$b; var d = a.c;");

    testSame("if (x) var a = {/** @nocollapse */ b: 0}; var c = 1; c = a.b; var d = a.c;");
  }

  @Test
  public void testGlobalVarSetToObjLitConditionally3() {
    testSame("var a; if (x) a = {b: 0}; else a = {b: 1}; var c = a.b;");

    testSame("var a; if (x) a = {b: 0}; else a = {/** @nocollapse */ b: 1};"
        + "var c = a.b;");
  }

  @Test
  public void testObjectPropertySetToObjLitConditionally() {
    test("var a = {}; if (x) a.b = {c: 0}; var d = a.b ? a.b.c : 0;",
         "if (x){ var a$b$c = 0; var a$b = {} } var d = a$b ? a$b$c : 0;");

    test(
        "var a = {}; if (x) a.b = {/** @nocollapse */ c: 0}; var d = a.b ? a.b.c : 0;",
        "if (x){ var a$b = {/** @nocollapse */ c: 0};} var d = a$b ? a$b.c : 0;");
  }

  @Test
  public void testFunctionPropertySetToObjLitConditionally() {
    test("function a() {} if (x) a.b = {c: 0}; var d = a.b ? a.b.c : 0;",
         "function a() {} if (x){ var a$b$c = 0; var a$b = {} }"
         + "var d = a$b ? a$b$c : 0;");

    testSame("function a() {} if (x) /** @nocollapse */ a.b = {c: 0};"
        + "var d = a.b ? a.b.c : 0;");

    test("function a() {} if (x) a.b = {/** @nocollapse */ c: 0}; var d = a.b ? a.b.c : 0;",
        "function a() {} if (x){ var a$b = {/** @nocollapse */ c: 0}; } var d = a$b ? a$b.c : 0;");
  }

  @Test
  public void testPrototypePropertySetToAnObjectLiteral() {
    test("var a = {b: function(){}}; a.b.prototype.c = {d: 0};",
        "var a$b = function(){}; a$b.prototype.c = {d: 0};");

    testSame("var a = {/** @nocollapse */ b: function(){}};"
        + "a.b.prototype.c = {d: 0};");
  }

  @Test
  public void testObjectPropertyResetInLocalScope() {
    test("var z = {}; z.a = 0; function f() {z.a = 5; return z.a}",
         "var z$a = 0; function f() {z$a = 5; return z$a}");

    testSame("var z = {}; z.a = 0;"
            + "function f() { /** @nocollapse */ z.a = 5; return z.a}");

    testSame("var z = {}; /** @nocollapse */ z.a = 0;"
        + "function f() {z.a = 5; return z.a}");
  }

  @Test
  public void testFunctionPropertyResetInLocalScope() {
    test("function z() {} z.a = 0; function f() {z.a = 5; return z.a}",
         "function z() {} var z$a = 0; function f() {z$a = 5; return z$a}");

    testSame("function z() {} /** @nocollapse */ z.a = 0;"
        + "function f() {z.a = 5; return z.a}");

    testSame("function z() {} z.a = 0;"
        + "function f() { /** @nocollapse */ z.a = 5; return z.a}");
  }

  @Test
  public void testNamespaceResetInGlobalScope1() {
    test(
        "var a = {}; /** @constructor */ a.b = function() {}; a = {};",
        "var a = {}; /** @constructor */ var a$b = function() {}; a = {};",
        warning(NAMESPACE_REDEFINED_WARNING));

    testSame("var a = {}; /** @constructor @nocollapse */a.b = function() {};"
        + "a = {};", NAMESPACE_REDEFINED_WARNING);
  }

  @Test
  public void testNamespaceResetInGlobalScope2() {
    test(
        "var a = {}; a = {}; /** @constructor */ a.b = function() {};",
        "var a = {}; a = {}; /** @constructor */ var a$b = function() {};",
        warning(NAMESPACE_REDEFINED_WARNING));

    testSame("var a = {}; a = {}; /** @constructor @nocollapse */a.b = function() {};",
        NAMESPACE_REDEFINED_WARNING);
  }

  @Test
  public void testNamespaceResetInGlobalScope3() {
    test("var a = {}; /** @constructor */ a.b = function() {}; a = a || {};",
         "var a = {}; /** @constructor */ var a$b = function() {}; a = a || {};");

    testSame("var a = {}; /** @constructor @nocollapse */ a.b = function() {}; a = a || {};");
  }

  @Test
  public void testNamespaceResetInGlobalScope4() {
    test("var a = {}; /** @constructor */ a.b = function() {}; var a = a || {};",
         "var a = {}; /** @constructor */ var a$b = function() {}; var a = a || {};");

    testSame("var a = {}; /** @constructor @nocollapse */a.b = function() {}; var a = a || {};");
  }

  @Test
  public void testNamespaceResetInLocalScope1() {
    test(
        "var a = {}; /** @constructor */ a.b = function() {}; function f() { a = {}; }",
        "var a = {}; /** @constructor */ var a$b = function() {}; function f() { a = {}; }",
        warning(NAMESPACE_REDEFINED_WARNING));

    testSame("var a = {}; /** @constructor @nocollapse */a.b = function() {};"
            + " function f() { a = {}; }",
        NAMESPACE_REDEFINED_WARNING);
  }

  @Test
  public void testNamespaceResetInLocalScope2() {
    test(
        "var a = {}; function f() { a = {}; } /** @constructor */ a.b = function() {};",
        "var a = {}; function f() { a = {}; } /** @constructor */ var a$b = function() {};",
        warning(NAMESPACE_REDEFINED_WARNING));

    testSame("var a = {}; function f() { a = {}; }"
            + " /** @constructor @nocollapse */a.b = function() {};",
        NAMESPACE_REDEFINED_WARNING);
  }

  @Test
  public void testNamespaceDefinedInLocalScope() {
    test(
        "var a = {}; (function() { a.b = {}; })(); /** @constructor */ a.b.c = function() {};",
        "var a$b; (function() { a$b = {}; })(); /** @constructor */ var a$b$c = function() {};");

    test(
        "var a = {}; (function() { /** @nocollapse */ a.b = {}; })();"
            + " /** @constructor */a.b.c = function() {};",
        "var a = {}; (function() { /** @nocollapse */ a.b = {}; })();"
            + " /** @constructor */ var a$b$c = function() {};");

    test(
        "var a = {}; (function() { a.b = {}; })();"
            + " /** @constructor @nocollapse */a.b.c = function() {};",
        "var a$b; (function() { a$b = {}; })();"
            + "/** @constructor @nocollapse */ a$b.c = function() {};");
  }

  @Test
  public void testAddPropertyToObjectInLocalScopeDepth1() {
    test("var a = {b: 0}; function f() { a.c = 5; return a.c; }",
         "var a$b = 0; var a$c; function f() { a$c = 5; return a$c; }");
  }

  @Test
  public void testAddPropertyToObjectInLocalScopeDepth2() {
    test("var a = {}; a.b = {}; (function() {a.b.c = 0;})(); x = a.b.c;",
         "var a$b$c; (function() {a$b$c = 0;})(); x = a$b$c;");
  }

  @Test
  public void testAddPropertyToFunctionInLocalScopeDepth1() {
    test("function a() {} function f() { a.c = 5; return a.c; }",
         "function a() {} var a$c; function f() { a$c = 5; return a$c; }");
  }

  @Test
  public void testAddPropertyToFunctionInLocalScopeDepth2() {
    test("var a = {}; a.b = function() {}; function f() {a.b.c = 0;}",
         "var a$b = function() {}; var a$b$c; function f() {a$b$c = 0;}");
  }

  @Test
  public void testAddPropertyToUncollapsibleFunctionInLocalScopeDepth1() {
    testSame("function a() {} var c = 1; c = a; (function() {a.b = 0;})(); a.b;");
  }

  @Test
  public void testAddPropertyToUncollapsibleFunctionInLocalScopeDepth2() {
    test("var a = {}; a.b = function (){}; var d = 1; d = a.b;"
         + "(function() {a.b.c = 0;})(); a.b.c;",
         "var a$b = function (){}; var d = 1; d = a$b;"
         + "(function() {a$b.c = 0;})(); a$b.c;");
  }

  @Test
  public void testResetObjectPropertyInLocalScope() {
    test("var a = {b: 0}; a.c = 1; function f() { a.c = 5; }",
         "var a$b = 0; var a$c = 1; function f() { a$c = 5; }");
  }

  @Test
  public void testResetFunctionPropertyInLocalScope() {
    test("function a() {}; a.c = 1; function f() { a.c = 5; }",
         "function a() {}; var a$c = 1; function f() { a$c = 5; }");
  }

  @Test
  public void testGlobalNameReferencedInLocalScopeBeforeDefined1() {
    // Because referencing global names earlier in the source code than they're
    // defined is such a common practice, we collapse them even though a runtime
    // exception could result (in the off-chance that the function gets called
    // before the alias variable is defined).
    test("var a = {b: 0}; function f() { a.c = 5; } a.c = 1;",
         "var a$b = 0; function f() { a$c = 5; } var a$c = 1;");
  }

  @Test
  public void testGlobalNameReferencedInLocalScopeBeforeDefined2() {
    test("var a = {b: 0}; function f() { return a.c; } a.c = 1;",
         "var a$b = 0; function f() { return a$c; } var a$c = 1;");
  }

  @Test
  public void testTwiceDefinedGlobalNameDepth1_1() {
    testSame("var a = {}; function f() { a.b(); }"
             + "a = function() {}; a.b = function() {};");
  }

  @Test
  public void testTwiceDefinedGlobalNameDepth1_2() {
    testSame("var a = {}; /** @constructor */ a = function() {};"
             + "a.b = {}; a.b.c = 0; function f() { a.b.d = 1; }");
  }

  @Test
  public void testTwiceDefinedGlobalNameDepth2() {
    test("var a = {}; a.b = {}; function f() { a.b.c(); }"
         + "a.b = function() {}; a.b.c = function() {};",
         "var a$b = {}; function f() { a$b.c(); }"
         + "a$b = function() {}; a$b.c = function() {};");
  }

  @Test
  public void testFunctionCallDepth1() {
    test("var a = {}; a.b = function(){}; var c = a.b();",
         "var a$b = function(){}; var c = a$b()");
  }

  @Test
  public void testFunctionCallDepth2() {
    test("var a = {}; a.b = {}; a.b.c = function(){}; a.b.c();",
         "var a$b$c = function(){}; a$b$c();");
  }

  @Test
  public void testFunctionAlias1() {
    test("var a = {}; a.b = {}; a.b.c = function(){}; a.b.d = a.b.c;a.b.d=null",
         "var a$b$c = function(){}; var a$b$d = a$b$c;a$b$d=null;");
  }

  @Test
  public void testCallToRedefinedFunction() {
    test("var a = {}; a.b = function(){}; a.b = function(){}; a.b();",
         "var a$b = function(){}; a$b = function(){}; a$b();");
  }

  @Test
  public void testCollapsePrototypeName() {
    test("var a = {}; a.b = {}; a.b.c = function(){}; "
         + "a.b.c.prototype.d = function(){}; (new a.b.c()).d();",
         "var a$b$c = function(){}; a$b$c.prototype.d = function(){}; "
         + "new a$b$c().d();");
  }

  @Test
  public void testReferencedPrototypeProperty() {
    test("var a = {b: {}}; a.b.c = function(){}; a.b.c.prototype.d = {};"
         + "e = a.b.c.prototype.d;",
         "var a$b$c = function(){}; a$b$c.prototype.d = {};"
         + "e = a$b$c.prototype.d;");
  }

  @Test
  public void testSetStaticAndPrototypePropertiesOnFunction() {
    test("var a = {}; a.b = function(){}; a.b.prototype.d = 0; a.b.c = 1;",
         "var a$b = function(){}; a$b.prototype.d = 0; var a$b$c = 1;");
  }

  @Test
  public void testReadUndefinedPropertyDepth1() {
    test("var a = {b: 0}; var c = a.d;",
         "var a$b = 0; var a = {}; var c = a.d;");
  }

  @Test
  public void testReadUndefinedPropertyDepth2() {
    test("var a = {b: {c: 0}}; f(a.b.c); f(a.b.d);",
         "var a$b$c = 0; var a$b = {}; f(a$b$c); f(a$b.d);");
  }

  @Test
  public void testCallUndefinedMethodOnObjLitDepth1() {
    test("var a = {b: 0}; a.c();",
         "var a$b = 0; var a = {}; a.c();");
  }

  @Test
  public void testCallUndefinedMethodOnObjLitDepth2() {
    test("var a = {b: {}}; a.b.c = function() {}; a.b.c(); a.b.d();",
         "var a$b = {}; var a$b$c = function() {}; a$b$c(); a$b.d();");
  }

  @Test
  public void testPropertiesOfAnUndefinedVar() {
    testSame("a.document = d; f(a.document.innerHTML);");
  }

  @Test
  public void testPropertyOfAnObjectThatIsNeitherFunctionNorObjLit() {
    testSame("var a = window; a.document = d; f(a.document)");
  }

  @Test
  public void testStaticFunctionReferencingThis1() {
    // Note: Google's JavaScript Style Guide says to avoid using the 'this'
    // keyword in a static function.
    test(
        "var a = {}; a.b = function() {this.c}; var d = 1; d = a.b;",
        "var a$b = function() {this.c}; var d = 1; d = a$b;",
        warning(CollapseProperties.UNSAFE_THIS));
  }

  @Test
  public void testStaticFunctionReferencingThis2() {
    // This gives no warning, because "this" is in a scope whose name is not
    // getting collapsed.
    test("var a = {}; "
         + "a.b = function() { return function(){ return this; }; };",
         "var a$b = function() { return function(){ return this; }; };");
  }

  @Test
  public void testStaticFunctionReferencingThis3() {
    test(
        "var a = {b: function() {this.c}};",
        "var a$b = function() { this.c };",
        warning(CollapseProperties.UNSAFE_THIS));
  }

  @Test
  public void testStaticFunctionReferencingThis4() {
    test("var a = {/** @this {Element} */ b: function() {this.c}};",
         "var a$b = function() { this.c };");
  }

  @Test
  public void testPrototypeMethodReferencingThis() {
    testSame("var A = function(){}; A.prototype = {b: function() {this.c}};");
  }

  @Test
  public void testConstructorReferencingThis() {
    test("var a = {}; "
         + "/** @constructor */ a.b = function() { this.a = 3; };",
         "/** @constructor */ var a$b = function() { this.a = 3; };");
  }

  @Test
  public void testRecordReferencingThis() {
    test("/** @const */ var a = {}; "
         + "/** @record */ a.b = function() { /** @type {string} */ this.a; };",
         "/** @record */ var a$b = function() { /** @type {string} */ this.a; };");
  }

  @Test
  public void testSafeReferenceOfThis() {
    test(
        "var a = {}; /** @this {Object} */ a.b = function() { this.a = 3; };",
        " /** @this {Object} */ var a$b = function() { this.a = 3; };");
  }

  @Test
  public void testGlobalFunctionReferenceOfThis() {
    testSame("var a = function() { this.a = 3; };");
  }

  @Test
  public void testFunctionGivenTwoNames() {
    // It's okay to collapse f's properties because g is not added to the
    // global scope as an alias for f. (Try it in your browser.)
    test("var f = function g() {}; f.a = 1; h(f.a);",
         "var f = function g() {}; var f$a = 1; h(f$a);");
  }

  @Test
  public void testObjLitWithUsedNumericKey() {
    testSame("a = {40: {}, c: {}}; var d = a[40]; var e = a.c;");
  }

  @Test
  public void testObjLitWithUnusedNumericKey() {
    test("var a = {40: {}, c: {}}; var e = 1; e =  a.c;",
         "var a$1 = {}; var a$c = {}; var e = 1; e = a$c");
  }

  @Test
  public void testObjLitWithNonIdentifierKeys() {
    testSame("a = {' ': 0, ',': 1}; var c = a[' '];");
    testSame("var FOO = {\n"
        + "  'bar': {\n"
        + "    'baz,qux': {\n"
        + "      'beep': 'xxxxx',\n"
        + "    },\n"
        + "  }\n"
        + "};"
        + "alert(FOO);");
  }

  @Test
  public void testChainedAssignments1() {
    test("var x = {}; x.y = a = 0;",
         "var x$y = a = 0;");
  }

  @Test
  public void testChainedAssignments2() {
    test("var x = {}; x.y = a = b = c();",
         "var x$y = a = b = c();");
  }

  @Test
  public void testChainedAssignments3() {
    test("var x = {y: 1}; a = b = x.y;",
         "var x$y = 1; a = b = x$y;");
  }

  @Test
  public void testChainedAssignments4() {
    testSame("var x = {}; a = b = x.y;");
  }

  @Test
  public void testChainedAssignments5() {
    test("var x = {}; a = x.y = 0;", "var x$y; a = x$y = 0;");
  }

  @Test
  public void testChainedAssignments6() {
    test("var x = {}; a = x.y = b = c();",
         "var x$y; a = x$y = b = c();");
  }

  @Test
  public void testChainedAssignments7() {
    test(
        "var x = {}; a = x.y = {}; /** @constructor */ x.y.z = function() {};",
        "var x$y; a = x$y = {}; /** @constructor */ var x$y$z = function() {};",
        warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testChainedVarAssignments1() {
    test("var x = {y: 1}; var a = x.y = 0;",
         "var x$y = 1; var a = x$y = 0;");
  }

  @Test
  public void testChainedVarAssignments2() {
    test("var x = {y: 1}; var a = x.y = b = 0;",
         "var x$y = 1; var a = x$y = b = 0;");
  }

  @Test
  public void testChainedVarAssignments3() {
    test("var x = {y: {z: 1}}; var b = 0; var a = x.y.z = 1; var c = 2;",
         "var x$y$z = 1; var b = 0; var a = x$y$z = 1; var c = 2;");
  }

  @Test
  public void testChainedVarAssignments4() {
    test("var x = {}; var a = b = x.y = 0;",
         "var x$y; var a = b = x$y = 0;");
  }

  @Test
  public void testChainedVarAssignments5() {
    test("var x = {y: {}}; var a = b = x.y.z = 0;",
         "var x$y$z; var a = b = x$y$z = 0;");
  }

  @Test
  public void testChainedVarAssignments6() {
    testSame("var a = x = 0; var x;");
  }

  @Test
  public void testChainedVarAssignments7() {
    testSame("x = {}; var a = x.y = 0; var x;");
  }

  @Test
  public void testPeerAndSubpropertyOfUncollapsibleProperty() {
    test("var x = {}; var a = x.y = 0; x.w = 1; x.y.z = 2;"
         + "b = x.w; c = x.y.z;",
         "var x$y; var a = x$y = 0; var x$w = 1; x$y.z = 2;"
         + "b = x$w; c = x$y.z;");
  }

  @Test
  public void testComplexAssignmentAfterInitialAssignment() {
    test("var d = {}; d.e = {}; d.e.f = 0; a = b = d.e.f = 1;",
         "var d$e$f = 0; a = b = d$e$f = 1;");
  }

  @Test
  public void testRenamePrefixOfUncollapsibleProperty() {
    test("var d = {}; d.e = {}; a = b = d.e.f = 0;",
         "var d$e$f; a = b = d$e$f = 0;");
  }

  @Test
  public void testNewOperator() {
    // Using the new operator on a name doesn't prevent its (static) properties
    // from getting collapsed.
    test("var a = {}; a.b = function() {}; a.b.c = 1; var d = new a.b();",
         "var a$b = function() {}; var a$b$c = 1; var d = new a$b();");
  }

  @Test
  public void testMethodCall() {
    test("var a = {}; a.b = function() {}; var d = a.b();",
         "var a$b = function() {}; var d = a$b();");
  }

  @Test
  public void testObjLitDefinedInLocalScopeIsLeftAlone() {
    test("var a = {}; a.b = function() {};"
         + "a.b.prototype.f_ = function() {"
         + "  var x = { p: '', q: '', r: ''}; var y = x.q;"
         + "};",
         "var a$b = function() {};"
         + "a$b.prototype.f_ = function() {"
         + "  var x = { p: '', q: '', r: ''}; var y = x.q;"
         + "};");
  }

  @Test
  public void testPropertiesOnBothSidesOfAssignment() {
    // This verifies that replacements are done in the right order. Collapsing
    // the l-value in an assignment affects the parse tree immediately above
    // the r-value, so we update all rvalues before any lvalues.
    test("var a = {b: 0}; a.c = a.b;a.c = null",
         "var a$b = 0; var a$c = a$b;a$c = null");
  }

  @Test
  public void testCallOnUndefinedProperty() {
    // The "inherits" property is not explicitly defined on a.b anywhere, but
    // it is accessed as though it certainly exists (it is called), so we infer
    // that it must be an uncollapsible property that has come into existence
    // some other way.
    test("var a = {}; a.b = function(){}; a.b.inherits(x);",
         "var a$b = function(){}; a$b.inherits(x);");
  }

  @Test
  public void testGetPropOnUndefinedProperty() {
    // The "superClass_" property is not explicitly defined on a.b anywhere,
    // but it is accessed as though it certainly exists (a subproperty of it
    // is accessed), so we infer that it must be an uncollapsible property that
    // has come into existence some other way.
    test("var a = {b: function(){}}; a.b.prototype.c ="
         + "function() { a.b.superClass_.c.call(this); }",
         "var a$b = function(){}; a$b.prototype.c ="
         + "function() { a$b.superClass_.c.call(this); }");
  }

  @Test
  public void testNonWellformedAlias1() {
    testSame("var a = {b: 3}; function f() { f(x); var x = a; f(x.b); }");
  }

  @Test
  public void testNonWellformedAlias2() {
    testSame("var a = {b: 3}; "
             + "function f() { if (false) { var x = a; f(x.b); } f(x); }");
  }

  @Test
  public void testInlineAliasWithModifications() {
    testSame("var x = 10; function f() { var y = x; x++; alert(y)} ");
    testSame("var x = 10; function f() { var y = x; x+=1; alert(y)} ");
    test("var x = {}; x.x = 10; function f() {var y=x.x; x.x++; alert(y)}",
         "var x$x = 10; function f() {var y=x$x; x$x++; alert(y)}");
    disableNormalize();
    test("var x = {}; x.x = 10; function f() {var y=x.x; x.x+=1; alert(y)}",
         "var x$x = 10; function f() {var y=x$x; x$x+=1; alert(y)}");
  }

  @Test
  public void testDoNotCollapsePropertyOnExternType() {
    testSame("String.myFunc = function() {}; String.myFunc()");
  }

  @Test
  public void testBug1704733() {
    String prelude =
        "function protect(x) { return x; }"
        + "function O() {}"
        + "protect(O).m1 = function() {};"
        + "protect(O).m2 = function() {};"
        + "protect(O).m3 = function() {};";

    testSame(prelude
        + "alert(O.m1); alert(O.m2()); alert(!O.m3);");
  }

  @Test
  public void testBug1956277() {
    test("var CONST = {}; CONST.URL = 3;",
         "var CONST$URL = 3;");
  }

  @Test
  public void testBug1974371() {
    test(
        "/** @enum {Object} */ var Foo = {A: {c: 2}, B: {c: 3}}; for (var key in Foo) {}",
        "var Foo$A = {c: 2}; var Foo$B = {c: 3};"
            + "/** @enum {Object} */ var Foo = {A: Foo$A, B: Foo$B};"
            + "for (var key in Foo) {}");
  }

  @Test
  public void testHasOwnProperty() {
    testSame("var a = {b: 3}; if (a.hasOwnProperty(foo)) { alert('ok'); }");
    testSame("var a = {b: 3}; if (a.hasOwnProperty(foo)) { alert('ok'); } a.b;");
  }

  @Test
  public void testHasOwnPropertyOnNonGlobalName() {
    testSame(lines(
        "/** @constructor */",
        "function A() {",
        "  this.foo = {a: 1, b: 1};",
        "}",
        "A.prototype.bar = function(prop) {",
        "  return this.foo.hasOwnProperty(prop);",
        "}"));
    testSame("var a = {'b': {'c': 1}}; a['b'].hasOwnProperty('c');");
    testSame("var a = {b: 3}; if (Object.prototype.hasOwnProperty.call(a, 'b')) { alert('ok'); }");
  }

  @Test
  public void testHasOwnPropertyNested() {
    test(
        "var a = {b: {c: 3}}; if (a.b.hasOwnProperty('c')) { alert('ok'); }",
        "var a$b =   {c: 3};  if (a$b.hasOwnProperty('c')) { alert('ok'); }");
    test(
        "var a = {b: {c: 3}}; if (a.b.hasOwnProperty('c')) { alert('ok'); } a.b.c;",
        "var a$b =   {c: 3};  if (a$b.hasOwnProperty('c')) { alert('ok'); } a$b.c;");
    test("var a = {}; a.b = function(p) { log(a.b.c.hasOwnProperty(p)); }; a.b.c = {};",
        "var a$b = function(p) { log(a$b$c.hasOwnProperty(p)); }; var a$b$c = {};");
}

  @Test
  public void testHasOwnPropertyMultiple() {
    testSame("var a = {b: 3, c: 4, d: 5}; if (a.hasOwnProperty(prop)) { alert('ok'); }");
  }

  @Test
  public void testObjectStaticMethodsPreventCollapsing() {
    testSame("var a = {b: 3}; alert(Object.getOwnPropertyDescriptor(a, 'b'));");
    testSame("var a = {b: 3}; alert(Object.getOwnPropertyDescriptors(a));");
    testSame("var a = {b: 3}; alert(Object.getOwnPropertyNames(a));");
    testSame("var a = {b: 3, [Symbol('c')]: 4}; alert(Object.getOwnPropertySymbols(a));");
  }

  private static final String COMMON_ENUM =
        "/** @enum {Object} */ var Foo = {A: {c: 2}, B: {c: 3}};";

  @Test
  public void testEnumOfObjects1() {
    test(
        COMMON_ENUM
        + "for (var key in Foo.A) {}",
         "var Foo$A = {c: 2}; var Foo$B$c = 3; for (var key in Foo$A) {}");
  }

  @Test
  public void testEnumOfObjects2() {
    test(
        COMMON_ENUM
        + "foo(Foo.A.c);",
         "var Foo$A$c = 2; var Foo$B$c = 3; foo(Foo$A$c);");
  }

  @Test
  public void testEnumOfObjects3() {
    test(
        "var x = {c: 2}; var y = {c: 3};"
            + "/** @enum {Object} */ var Foo = {A: x, B: y};"
            + "for (var key in Foo) {}",
        "var x = {c: 2}; var y = {c: 3};"
            + "var Foo$A = x; var Foo$B = y; /** @enum {Object} */ var Foo = {A: Foo$A, B: Foo$B};"
            + "for (var key in Foo) {}");
  }

  @Test
  public void testEnumOfObjects4() {
    // Note that this produces bad code, but that's OK, because
    // checkConsts will yell at you for reassigning an enum value.
    // (enum values have to be constant).
    test(
        COMMON_ENUM + "for (var key in Foo) {} Foo.A = 3; alert(Foo.A);",
        "var Foo$A = {c: 2}; var Foo$B = {c: 3};"
            + "/** @enum {Object} */ var Foo = {A: Foo$A, B: Foo$B};"
            + "for (var key in Foo) {} Foo$A = 3; alert(Foo$A);");
  }

  @Test
  public void testObjectOfObjects1() {
    // Basically the same as testEnumOfObjects4, but without the
    // constant enum values.
    testSame("var Foo = {a: {c: 2}, b: {c: 3}}; for (var key in Foo) {} Foo.a = 3; alert(Foo.a);");
  }

  @Test
  public void testReferenceInAnonymousObject0() {
    test("var a = {};"
         + "a.b = function(){};"
         + "a.b.prototype.c = function(){};"
         + "var d = a.b.prototype.c;",
         "var a$b = function(){};"
         + "a$b.prototype.c = function(){};"
         + "var d = a$b.prototype.c;");
  }

  @Test
  public void testReferenceInAnonymousObject1() {
    test("var a = {};"
         + "a.b = function(){};"
         + "var d = a.b.prototype.c;",
         "var a$b = function(){};"
         + "var d = a$b.prototype.c;");
  }

  @Test
  public void testReferenceInAnonymousObject2() {
    test("var a = {};"
         + "a.b = function(){};"
         + "a.b.prototype.c = function(){};"
         + "var d = {c: a.b.prototype.c};",
         "var a$b = function(){};"
         + "a$b.prototype.c = function(){};"
         + "var d$c = a$b.prototype.c;");
  }

  @Test
  public void testReferenceInAnonymousObject3() {
    test("function CreateClass(a$jscomp$1) {}"
         + "var a = {};"
         + "a.b = function(){};"
         + "a.b.prototype.c = function(){};"
         + "a.d = CreateClass({c: a.b.prototype.c});",
         "function CreateClass(a$jscomp$1) {}"
         + "var a$b = function(){};"
         + "a$b.prototype.c = function(){};"
         + "var a$d = CreateClass({c: a$b.prototype.c});");
  }

  @Test
  public void testReferenceInAnonymousObject4() {
    test("function CreateClass(a) {}"
         + "var a = {};"
         + "a.b = CreateClass({c: function() {}});"
         + "a.d = CreateClass({c: a.b.c});",
         "function CreateClass(a$jscomp$1) {}"
         + "var a$b = CreateClass({c: function() {}});"
         + "var a$d = CreateClass({c: a$b.c});");
  }

  @Test
  public void testReferenceInAnonymousObject5() {
    test("function CreateClass(a) {}"
         + "var a = {};"
         + "a.b = CreateClass({c: function() {}});"
         + "a.d = CreateClass({c: a.b.prototype.c});",
         "function CreateClass(a$jscomp$1) {}"
         + "var a$b = CreateClass({c: function() {}});"
         + "var a$d = CreateClass({c: a$b.prototype.c});");
  }

  @Test
  public void testCrashInNestedAssign() {
    test("var a = {}; if (a.b = function() {}) a.b();",
         "var a$b; if (a$b=function() {}) { a$b(); }");
  }

  @Test
  public void testTwinReferenceCancelsChildCollapsing() {
    test("var a = {}; if (a.b = function() {}) { a.b.c = 3; a.b(a.b.c); }",
         "var a$b; if (a$b = function() {}) { a$b.c = 3; a$b(a$b.c); }");
  }

  @Test
  public void testPropWithDollarSign() {
    test("var a = {$: 3}", "var a$$0 = 3;");
  }

  @Test
  public void testPropWithDollarSign2() {
    test("var a = {$: function(){}}", "var a$$0 = function(){};");
  }

  @Test
  public void testPropWithDollarSign3() {
    test("var a = {b: {c: 3}, b$c: function(){}}",
         "var a$b$c = 3; var a$b$0c = function(){};");
  }

  @Test
  public void testPropWithDollarSign4() {
    test("var a = {$$: {$$$: 3}};", "var a$$0$0$$0$0$0 = 3;");
  }

  @Test
  public void testPropWithDollarSign5() {
    test("var a = {b: {$0c: true}, b$0c: false};",
         "var a$b$$00c = true; var a$b$00c = false;");
  }

  @Test
  public void testConstKey() {
    test("var foo = {A: 3};", "var foo$A = 3;");
  }

  @Test
  public void testPropertyOnGlobalCtor() {
    test("/** @constructor */ function Map() {} Map.foo = 3; Map;",
         "/** @constructor */ function Map() {} var Map$foo = 3; Map;");
  }

  @Test
  public void testPropertyOnGlobalInterface() {
    test("/** @interface */ function Map() {} Map.foo = 3; Map;",
         "/** @interface */ function Map() {} var Map$foo = 3; Map;");
  }

  @Test
  public void testPropertyOnGlobalFunction() {
    testSame("function Map() {} Map.foo = 3; alert(Map);");
  }

  @Test
  public void testIssue389() {
    test("function alias() {}"
    + "var dojo = {};"
    + "dojo.gfx = {};"
    + "dojo.declare = function() {};"
    + "/** @constructor */"
    + "dojo.gfx.Shape = function() {};"
    + "dojo.gfx.Shape = dojo.declare('dojo.gfx.Shape');"
    + "alias(dojo);", "function alias() {}"
    + "var dojo = {};"
    + "dojo.gfx = {};"
    + "dojo.declare = function() {};"
    + "/** @constructor */"
    + "var dojo$gfx$Shape = function() {};"
    + "dojo$gfx$Shape = dojo.declare('dojo.gfx.Shape');"
    + "alias(dojo);", warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAliasedTopLevelName() {
    testSame(
        "function alias() {}"
        + "var dojo = {};"
        + "dojo.gfx = {};"
        + "dojo.declare = function() {};"
        + "dojo.gfx.Shape = {SQUARE: 2};"
        + "dojo.gfx.Shape = dojo.declare('dojo.gfx.Shape');"
        + "alias(dojo);"
        + "alias(dojo$gfx$Shape$SQUARE);");
  }

  @Test
  public void testAliasedTopLevelEnum() {
    test("function alias() {}"
    + "var dojo = {};"
    + "dojo.gfx = {};"
    + "dojo.declare = function() {};"
    + "/** @enum {number} */"
    + "dojo.gfx.Shape = {SQUARE: 2};"
    + "dojo.gfx.Shape = dojo.declare('dojo.gfx.Shape');"
    + "alias(dojo);"
    + "alias(dojo.gfx.Shape.SQUARE);", "function alias() {}"
    + "var dojo = {};"
    + "dojo.gfx = {};"
    + "dojo.declare = function() {};"
    + "/** @enum {number} */"
    + "var dojo$gfx$Shape = {SQUARE: 2};"
    + "dojo$gfx$Shape = dojo.declare('dojo.gfx.Shape');"
    + "alias(dojo);"
    + "alias(dojo$gfx$Shape.SQUARE);", warning(UNSAFE_NAMESPACE_WARNING));
  }

  @Test
  public void testAssignFunctionBeforeDefinition() {
    testSame(
        "f = function() {};"
        + "var f = null;");
  }

  @Test
  public void testObjectLitBeforeDefinition() {
    testSame(
        "a = {b: 3};"
        + "var a = null;"
        + "this.c = a.b;");
  }

  @Test
  public void testTypedef1() {
    test("var foo = {};"
         + "/** @typedef {number} */ foo.Baz;",
         "var foo = {}; var foo$Baz;");
  }

  @Test
  public void testTypedef2() {
    test("var foo = {};"
         + "/** @typedef {number} */ foo.Bar.Baz;"
         + "foo.Bar = function() {};",
         "var foo$Bar$Baz; var foo$Bar = function(){};");
  }

  @Test
  public void testDelete1() {
    testSame(
        "var foo = {};"
        + "foo.bar = 3;"
        + "delete foo.bar;");
  }

  @Test
  public void testDelete2() {
    test(
        "var foo = {};"
        + "foo.bar = 3;"
        + "foo.baz = 3;"
        + "delete foo.bar;",
        "var foo = {};"
        + "foo.bar = 3;"
        + "var foo$baz = 3;"
        + "delete foo.bar;");
  }

  @Test
  public void testDelete3() {
    testSame(
        "var foo = {bar: 3};"
        + "delete foo.bar;");
  }

  @Test
  public void testDelete4() {
    test(
        "var foo = {bar: 3, baz: 3};"
        + "delete foo.bar;",
        "var foo$baz=3;var foo={bar:3};delete foo.bar");
  }

  @Test
  public void testDelete5() {
    test(
        "var x = {};"
        + "x.foo = {};"
        + "x.foo.bar = 3;"
        + "delete x.foo.bar;",
        "var x$foo = {};"
        + "x$foo.bar = 3;"
        + "delete x$foo.bar;");
  }

  @Test
  public void testDelete6() {
    test(
        "var x = {};"
        + "x.foo = {};"
        + "x.foo.bar = 3;"
        + "x.foo.baz = 3;"
        + "delete x.foo.bar;",
        "var x$foo = {};"
        + "x$foo.bar = 3;"
        + "var x$foo$baz = 3;"
        + "delete x$foo.bar;");
  }

  @Test
  public void testDelete7() {
    test(
        "var x = {};"
        + "x.foo = {bar: 3};"
        + "delete x.foo.bar;",
        "var x$foo = {bar: 3};"
        + "delete x$foo.bar;");
  }

  @Test
  public void testDelete8() {
    test(
        "var x = {};"
        + "x.foo = {bar: 3, baz: 3};"
        + "delete x.foo.bar;",
        "var x$foo$baz = 3; var x$foo = {bar: 3};"
        + "delete x$foo.bar;");
  }

  @Test
  public void testDelete9() {
    testSame(
        "var x = {};"
        + "x.foo = {};"
        + "x.foo.bar = 3;"
        + "delete x.foo;");
  }

  @Test
  public void testDelete10() {
    testSame(
        "var x = {};"
        + "x.foo = {bar: 3};"
        + "delete x.foo;");
  }

  @Test
  public void testDelete11() {
    // Constructors are always collapsed.
    test("var x = {};"
    + "x.foo = {};"
    + "/** @constructor */ x.foo.Bar = function() {};"
    + "delete x.foo;", "var x = {};"
    + "x.foo = {};"
    + "/** @constructor */ var x$foo$Bar = function() {};"
    + "delete x.foo;", warning(NAMESPACE_REDEFINED_WARNING));
  }

  @Test
  public void testPreserveConstructorDoc() {
    test(
        "var foo = {}; /** @constructor */ foo.bar = function() {}",
        "/** @constructor */ var foo$bar = function() {}");
  }

  @Test
  public void testTypeDefAlias2() {
    // TODO(johnlenz): make CollapseProperties safer around aliases of
    // functions and object literals.  Currently, this pass trades correctness
    // for code size.  We should able to create a safer compromise by teaching
    // the pass about goog.inherits and similiar calls.
    test(
        "/** @constructor */ var D = function() {};\n"
            + "/** @constructor */ D.L = function() {};\n"
            + "/** @type {D.L} */ D.L.A = new D.L();\n"
            + "\n"
            + "/** @const */ var M = {};\n"
            + "if (random) { /** @typedef {D.L} */ M.L = D.L; }\n"
            + "\n"
            + "use(M.L);\n"
            + "use(M.L.A);\n",
        "/** @constructor */ var D = function() {};\n"
            + "/** @constructor */ var D$L = function() {};\n"
            + "/** @type {D.L} */ var D$L$A = new D$L();\n"
            + "if (random) { /** @typedef {D.L} */ var M$L = D$L; }\n"
            + "use(M$L);\n"
            + "use(M$L.A);");
  }

  @Test
  public void testGlobalCatch() {
    testSame(
        "try {"
        + "  throw Error();"
        + "} catch (e) {"
        + "  console.log(e.name)"
        + "}");
  }

  @Test
  public void testCtorManyAssignmentsDontInlineDontWarn() {
    test(
        "var a = {};\n"
            + "/** @constructor */ a.b = function() {};\n"
            + "a.b.staticProp = 5;\n"
            + "function f(y, z) {\n"
            + "  var x = a.b;\n"
            + "  if (y) {\n"
            + "    x = z;\n"
            + "  }\n"
            + "  return new x();\n"
            + "}",
        "/** @constructor */"
            + "var a$b = function() {};\n"
            + "var a$b$staticProp = 5;\n"
            + "function f(y, z) {\n"
            + "  var x = a$b;\n"
            + "  if (y) {\n"
            + "    x = z;\n"
            + "  }\n"
            + "  return new x();\n"
            + "}");
  }

  @Test
  public void testExpressionResultReferenceWontPreventCollapse() {
    test("var ns = {};\n"
        + "ns.Outer = {};\n"
        + "\n"
        + "ns.Outer;\n"
        + "ns.Outer.Inner = function() {}\n",

        "var ns$Outer={};\n"
        + "ns$Outer;\n"
        + "var ns$Outer$Inner=function(){};\n");
  }

  @Test
  public void testNoCollapseWithInvalidEnums() {
    test(
        "/** @enum { { a: { b: number}} } */"
            + "var e = { KEY1: { a: { /** @nocollapse */ b: 123}},\n"
            + "  KEY2: { a: { b: 456}}\n"
            + "}",
        "var e$KEY1$a={/** @nocollapse */ b:123}; var e$KEY2$a$b=456;");

    test(
        "/** @enum */ var e = { A: 1, B: 2 };\n"
            + "/** @type {{ c: { d: number } }} */ e.name1 = {"
            + "  c: { /** @nocollapse */ d: 123 } };",
        "var e$A=1; var e$B=2; var e$name1$c={/** @nocollapse */ /** @nocollapse */ d:123};");

    test(
        "/** @enum */ var e = { A: 1, B: 2}; /** @nocollapse */ e.foo = { bar: true };",
        "var e$A=1; var e$B=2; /** @enum */ var e = {}; /** @nocollapse */ e.foo = { bar: true };");
  }

  @Test
  public void testDontCrashNamespaceAliasAcrossScopes() {
    test(
        "var ns = {};\n"
        + "ns.VALUE = 0.01;\n"
        + "function f() {\n"
        + "    var constants = ns;\n"
        + "    (function() {\n"
        + "       var x = constants.VALUE;\n"
        + "    })();\n"
        + "}",
        null);
  }

  @Test
  public void testCollapsedNameAlreadyTaken() {
    test(
        lines(
            "/** @constructor */ function Funny$Name(){};",
            "function Funny(){};",
            "Funny.Name = 5;",
            "var x = new Funny$Name();"),
        lines(
            "/** @constructor */ function Funny$Name(){};",
            "function Funny(){};",
            "var Funny$Name$1 = 5;",
            "var x = new Funny$Name();"));

    test("var ns$x = 0; var ns$x$0 = 1; var ns = {}; ns.x = 8;",
         "var ns$x = 0; var ns$x$0 = 1; var ns$x$1 = 8;");

    test("var ns$x = 0; var ns$x$0 = 1; var ns$x$1 = 2; var ns = {}; ns.x = 8;",
         "var ns$x = 0; var ns$x$0 = 1; var ns$x$1 = 2; var ns$x$2 = 8;");

    test("var ns$x = {}; ns$x.y = 2; var ns = {}; ns.x = {}; ns.x.y = 8;",
         "var ns$x$y = 2; var ns$x$1$y = 8;");

    test("var ns$x = {}; ns$x.y = 1; var ns = {}; ns.x$ = {}; ns.x$.y = 2; ns.x = {}; ns.x.y = 3;",
         "var ns$x$y = 1; var ns$x$0$y = 2; var ns$x$1$y = 3;");
  }

  // New Es6 Feature Tests - Some do not pass yet.
  @Test
  public void testArrowFunctionProperties() {
    // Add property to arrow function in local scope
    test(
        "function a() {} () => { a.c = 5; return a.c; }",
        "function a() {} var a$c; () => { a$c = 5; return a$c; }");

    // Reassign function property
    test(
        "function a() {}; a.c = 1; () => { a.c = 5; }",
        "function a() {}; var a$c = 1; () => { a$c = 5; }");

    // Arrow function assignment
    test(
        "var a = () => {}; function f() { a.c = 5; }",
        "var a = () => {}; var a$c; function f() { a$c = 5; }");
  }

  @Test
  public void testDestructuredProperiesObjectLit() {
    // Using destructuring shorthand
    test(
        "var { a, b } = { a: {}, b: {} }; a.a = 5; var c = a.a; ",
        //"var { a, b } = { a: {}, b: {} }; a$a = 5; var c = a$a; ");
        "var {a:a,b:b}={a:{},b:{}};a.a=5;var c=a.a");

    // Without destructuring shorthand
    test(
        "var { a:a, b:b } = { a: {}, b: {} }; a.a = 5; var c = a.a; ",
        //"var { a:a, b:b } = { a: {}, b: {} }; a$a = 5; var c = a$a; ");
        "var {a:a,b:b}={a:{},b:{}};a.a=5;var c=a.a");

    // Test with greater depth
    test(
        "var { a, b } = { a: {}, b: {} }; a.a.a = 5; var c = a.a; var d = c.a;",
        //"var { a, b } = { a: {}, b: {} }; a$a$a = 5; var c = a$a; var d = c$a;");
        "var {a:a,b:b}={a:{},b:{}};a.a.a=5;var c=a.a;var d=c.a");
  }

  @Test
  public void testCanCollapseSinglePropertyInObjectPattern() {
    test(
        "const x = {y: 1}; const {y} = x; use(y);",
        "var x$y = 1; const x = {}; const {} = x; const y = x$y; use(y);");
  }

  @Test
  public void testCanCollapseSinglePropertyInObjectPatternWithDefaultValue() {
    test(
        "const x = {y: 1}; const {y = 0} = x; use(y);",
        "var x$y = 1; const x = {}; const {} = x; const y = void 0 === x$y ? 0 : x$y; use(y);");
  }

  @Test
  public void testCanCollapsePropertyInObjectPatternWithKeyBefore() {
    test(
        "let x = {y: 1, /** @nocollapse */ z: 2}; let {z, y} = x; use(y, z);",
        "var x$y = 1; let x = {/** @nocollapse */ z: 2}; let {z} = x; let y = x$y; use(y, z);");
  }

  @Test
  public void testCanCollapsePropertyInObjectPatternWithKeyAfter() {
    test(
        "let x = {y: 1, /** @nocollapse */ z: 2}; let {y, z=y} = x; use(y, z);",
        "var x$y = 1; let x = {/** @nocollapse */ z: 2}; let y = x$y; let {z=y} = x; use(y, z);");
  }

  @Test
  public void testCanCollapsePropertyInObjectPatternWithKeyBeforeAndAfter() {
    test(
        lines(
            "let  foo = {bar: {y: 1}};", //
            "let {x1, x2, y, z1, z2} =  foo.bar;",
            "use(x1, x2, y, z1, z2);"),
        lines(
            "var foo$bar$y = 1;",
            "var foo$bar = {};",
            "let {x1, x2} = foo$bar;", // don't collapse x1 etc. because they're undefined
            "let y = foo$bar$y;",
            "let {z1, z2} = foo$bar;",
            "use(x1, x2, y, z1, z2);"));
  }

  @Test
  public void testCannotCollapsePropertyInNestedObjectPattern() {
    test(
        "const x = {y: {z: 1}}; const {y: {z}} = x; use(z);",
        "var x$y = {z: 1}; const x = {}; const {} = x; const {z} = x$y; use(z);");
  }

  @Test
  public void testCanCollapseSinglePropertyInObjectPatternAssign() {
    test(
        "const x = {y: 1}; var y; ({y} = x); use(y);",
        "var x$y = 1; const x = {}; var y; ({} = x, y = x$y); use(y);");
  }

  @Test
  public void testCanCollapseSinglePropertyInObjectPatternInForLoopClosure() {
    test(
        "const x = {y: 1}; for (const {y} = x; true;) { use(() => y); }",
        "var x$y = 1; const x = {}; for (const {} = x, y = x$y; true;) { use(() => y); }");
  }

  @Test
  public void testPropertyInArray() {
    testSame("var a, b = [{}, {}]; a.foo = 5; b.bar = 6;");

    test("var a = {}; a.b = 5; var c, d = [6, a.b]", "var a$b = 5; var c, d = [6, a$b];");
  }

  @Test
  public void testCollapsePropertySetInPattern() {
    // TODO(b/120303257): collapse lvalues in destructuring patterns. We delayed implementing this
    // because it's uncommon to have properties as lvalues in destructuring patterns.
    test(
        "var a = {}; a.b = {}; [a.b.c, a.b.d] = [1, 2];", "var a$b = {}; [a$b.c, a$b.d] = [1, 2];");

    test(
        "var a = {}; a.b = {}; ({x: a.b.c, y: a.b.d} = {});",
        "var a$b = {}; ({x: a$b.c, y: a$b.d} = {});");
  }

  @Test
  public void testDontCollapsePropertiesOfSpreadNamespace() {
    // Notice we can still collapse the parent namespace, `a`.
    test(
        "var a = {b: {c: 0}}; var d = {...a.b}; use(a.b.c);", //
        "var a$b = {c: 0}; use(a$b.c);");
  }

  @Test
  public void testDontCollapsePropertiesOfRestedNamespace() {
    test(
        "var a = {b: {c: 0}}; var {...d} = a.b; use(a.b.c);", //
        // `d` is a dead name that will be eliminated by other optimzation.
        "var a$b = {c: 0}; var {...d} = a$b; use(a$b.c);");

    // "a.b.c" is not aliased by the REST in this case.
    test(
        "var a = {b: {c: 0}}; var {d: {...d}} = a.b; use(a.b.c);", //
        "var a$b$c = 0; var a$b = {}; var {d: {...d}} = a$b; use(a$b$c);");
  }

  @Test
  public void testCollapsePropertiesWhenDeclaredInObjectLitWithSpread() {
    testSame("var a = {b: 0, ...c}; use(a.b);");

    testSame("var a = {...c}; use(a.b);");

    test(
        "var a = {...c, b: 0}; use(a.b);", //
        "var a$b = 0; use(a$b);");
  }

  @Test
  public void testComputedPropertyNames() {
    // Computed property in object literal. This following test code is bad style - it does not
    // follow the assumptions of the pass and thus produces the following output.

    test(
        lines(
            "var a = {",
            "  ['val' + ++i]: i,",
            "  ['val' + ++i]: i",
            "};",
            "a.val1;"),
        lines(
            "var a = {",
            "  ['val' + ++i]: i,",
            "  ['val' + ++i]: i",
            "};",
            "var a$val1;"));

    test(
        "var a = { ['val']: i, ['val']: i }; a.val;",
        "var a = { ['val']: i, ['val']: i }; var a$val;");

    // Computed property method name in class
    testSame(
        lines(
            "class Bar {",
            "  constructor(){}",
            "  ['f'+'oo']() {",
            "    return 1",
            "  }",
            "}",
            "var bar = new Bar()",
            "bar.foo();"));

    // Computed property method name in class - no concatenation
    testSame(
        lines(
            "class Bar {",
            "  constructor(){}",
            "  ['foo']() {",
            "    return 1",
            "  }",
            "}",
            "var bar = new Bar()",
            "bar.foo();"));
  }

  @Test
  public void testClassGetSetMembers() {
    // Get and set methods
    testSame(
        lines(
            "class Bar {",
            "  constructor(x) {",
            "    this.x = x;",
            "  }",
            "  get foo() {",
            "    return this.x;",
            "  }",
            "  set foo(xIn) {",
            "    x = xIn;",
            "  }",
            "}",
            "var bar = new Bar(1);",
            "bar.foo;",
            "bar.foo = 2;"));
  }

  @Test
  public void testClassNonStaticMembers() {
    // Call class method inside class scope
    testSame(
        lines(
            "function getA() {};",
            "class Bar {",
            "  constructor(){}",
            "  getA() {",
            "    return 1;",
            "  }",
            "  getB(x) {",
            "    this.getA();",
            "  }",
            "}"));

    // Call class method outside class scope
    testSame(
        lines(
            "class Bar {",
            "  constructor(){}",
            "  getB(x) {}",
            "}",
            "var too;",
            "var too = new Bar();",
            "too.getB(too);"));

    // Non-static method
    testSame(
        lines(
            "class Bar {",
            "  constructor(x){",
            "    this.x = x;",
            "  }",
            "  double() {",
            "    return x*2;",
            "  }",
            "}",
            "var too;",
            "var too = new Bar();",
            "too.double(1);"));
  }

  @Test
  public void testClassDeclarationWithStaticMembers() {
    test(
        "class Bar { static double(n) { return n*2; } } Bar.double(1);",
        "var Bar$double = function(n) { return n * 2; }; class Bar {} Bar$double(1);");
  }

  @Test
  public void testClassAssignmentWithStaticMembers() {
    test(
        "const ns = {}; ns.Bar = class { static double(n) { return n*2; } }; ns.Bar.double(1);",
        lines(
            "var ns$Bar$double = function(n) { return n * 2; }",
            "var ns$Bar = class {}",
            "ns$Bar$double(1);"));
  }

  @Test
  public void testClassWithMultipleStaticMembers() {
    test(
        lines(
            "class Bar {",
            "  static double(n) {",
            "    return n*2",
            "  }",
            "  static triple(n) {",
            "    return n*3;",
            "  }",
            "}",
            "Bar.double(1);",
            "Bar.triple(2);"),
        lines(
            "var Bar$double = function(n) { return n * 2; }",
            "var Bar$triple = function(n) { return n * 3; }",
            "class Bar {}",
            "Bar$double(1);",
            "Bar$triple(2);"));
  }

  @Test
  public void testClassStaticMembersWithAdditionalUndeclaredProperty() {
    test(
        lines(
            "class Bar {",
            "  static double(n) {",
            "    return n*2",
            "  }",
            "}",
            "use(Bar.double.trouble);"),
        lines(
            "var Bar$double = function(n) { return n * 2; }",
            "class Bar {}",
            "use(Bar$double.trouble);"));
  }

  @Test
  public void testClassStaticMembersWithAdditionalPropertySetLocally() {
    test(
        lines(
            "class Bar {",
            "  static double(n) {",
            "    return n*2",
            "  }",
            "}",
            "(function() { Bar.double.trouble = -1; })();",
            "use(Bar.double.trouble);"),
        lines(
            "var Bar$double = function(n) { return n * 2; }",
            "class Bar {}",
            "var Bar$double$trouble;",
            "(function() { Bar$double$trouble = -1; })();",
            "use(Bar$double$trouble);"));
  }

  @Test
  public void testClassStaticMembersWithAdditionalPropertySetGlobally() {
    test(
        lines(
            "class Bar {",
            "  static double(n) {",
            "    return n*2",
            "  }",
            "}",
            "Bar.double.trouble = -1;",
            "use(Bar.double.trouble);"),
        lines(
            "var Bar$double = function(n) { return n * 2; }",
            "class Bar {}",
            "var Bar$double$trouble = -1;",
            "use(Bar$double$trouble);"));
  }

  @Test
  public void testClassDeclarationWithEscapedStaticMember_collapsesMemberButNotMemberProp() {
    test(
        lines(
            "class Bar {", //
            "  static double(n) {",
            "    return n*2",
            "  }",
            "}",
            "Bar.double.trouble = 4;",
            "use(Bar.double);",
            "use(Bar.double.trouble);"),
        lines(
            "var Bar$double = function(n) { return n * 2; }",
            "class Bar {}",
            // don't collapse this property because Bar$double is escaped
            "Bar$double.trouble = 4;",
            "use(Bar$double);",
            "use(Bar$double.trouble);"));
  }

  @Test
  public void testClassDeclarationWithStaticMembersWithNoCollapse() {
    testSame(
        lines(
            "class Bar {",
            "  /** @nocollapse */",
            "  static double(n) {",
            "    return n*2",
            "  }",
            "}",
            "Bar.double(1);"));
  }

  @Test
  public void testClassStaticMemberWithUnreferencedInnerName() {
    test(
        lines(
            "const Bar = class BarInternal {",
            "  static baz(n) {",
            "    use(n);",
            "  }",
            "}",
            "Bar.baz();"),
        lines(
            "var Bar$baz = function(n) { use(n); }",
            "const Bar = class BarInternal {}",
            "Bar$baz();"));
  }

  @Test
  public void testDontCollapseClassStaticMemberReferencingInnerName() {
    // probably we could do some rewriting to make this work, but for now just back off.
    testSame(
        lines(
            "const Bar = class BarInternal {",
            "  static baz(n) {",
            "    use(BarInternal);",
            "  }",
            "}",
            "Bar.baz();"));
  }

  @Test
  public void testDontCollapseClassStaticMemberReferencingInnerNameInNestedFunction() {
    // probably we could do some rewriting to make this work, but for now just back off.
    testSame(
        lines(
            "const Bar = class BarInternal {",
            "  static baz(n) {",
            "    return function() { use(BarInternal); };",
            "  }",
            "}",
            "Bar.baz();"));
  }

  @Test
  public void testClassStaticMemberUsingSuperNotCollapsed() {
    testSame(
        lines(
            "class Baz extends Bar() {",
            "  static quadruple(n) {",
            "    return 2 * super.double(n);",
            " }",
            "}"));
  }

  @Test
  public void testClassStaticMemberUsingSuperInArrowFnNotCollapsed() {
    testSame(
        lines(
            "class Baz extends Bar() {",
            "  static quadruple(n) {",
            "    return () => 2 * super.double(n);",
            " }",
            "}"));
  }

  @Test
  public void testClassStaticMemberWithInnerClassUsingSuperIsCollapsed() {
    test(
        lines(
            "class Bar extends fn() {",
            "  static m() {",
            "    class Inner extends fn() {",
            "      static n() { super.n(); } ", // does not block collapsing Bar.m
            "    }",
            "  }",
            "}"),
        lines(
            "var Bar$m = function() {",
            "  class Inner extends fn() {",
            "    static n() { super.n(); } ",
            "  }",
            "};",
            "class Bar extends fn() {}"));
  }

  @Test
  public void testEs6StaticMemberAddedAfterDefinition() {
    test(
        lines(
            "class Bar {}", //
            "Bar.double = function(n) {",
            "  return n*2",
            "}",
            "Bar.double(1);"),
        lines(
            "class Bar {}",
            "var Bar$double = function(n) {",
            "  return n*2",
            "}",
            "Bar$double(1);"));
  }

  @Test
  public void testEs6StaticMemberOnEscapedClassIsCollapsed() {
    test(
        "class Bar { static m() {} } use(Bar);",
        "var Bar$m = function() {}; class Bar {} use(Bar);");
  }

  @Test
  public void testClassStaticProperties() {
    test("class A {} A.foo = 'bar'; use(A.foo);", "class A {} var A$foo = 'bar'; use(A$foo);");

    // Collapsing A.foo is known to be unsafe.
    test(
        srcs("class A { static useFoo() { alert(this.foo); } } A.foo = 'bar'; A.useFoo();"),
        expected(
            lines(
                "var A$useFoo = function() { alert(this.foo); };",
                "class A {}",
                "var A$foo = 'bar';",
                "A$useFoo();")),
        warning(UNSAFE_THIS));

    test(
        srcs(
            lines(
                "class A {",
                "  static useFoo() {",
                "    alert(this.foo);",
                "  }",
                "}",
                "/** @nocollapse */",
                "A.foo = 'bar';",
                "A.useFoo();")),
        expected(
            lines(
                "var A$useFoo = function() { alert(this.foo); }; ",
                "class A {}",
                "/** @nocollapse */",
                "A.foo = 'bar';",
                "A$useFoo();")),
        warning(UNSAFE_THIS));
  }

  @Test
  public void testClassStaticAndPrototypePropWithSameName() {
    test(
        "const ns = {}; ns.C = class { x() {} }; ns.C.x = 3;",
        "var ns$C = class { x() {} }; var ns$C$x = 3;");
  }

  @Test
  public void testClassStaticProperties_locallyDeclared1() {
    test(
        lines(
            "class A {}",
            "function addStaticPropToA() {",
            "  A.staticProp = 5;",
            "}",
            "if (A.staticProp) {",
            "  use(A.staticProp);",
            "}"),
        lines(
            "class A {}",
            "var A$staticProp;",
            "function addStaticPropToA() {",
            "  A$staticProp = 5;",
            "}",
            "if (A$staticProp) {",
            "  use(A$staticProp);",
            "}"));
  }

  @Test
  public void testClassStaticProperties_locallyDeclared2() {
    test(
        lines(
            "const A = class {}",
            "function addStaticPropToA() {",
            "  A.staticProp = 5;",
            "}",
            "if (A.staticProp) {",
            "  use(A.staticProp);",
            "}"),
        lines(
            "const A = class {}",
            "var A$staticProp;",
            "function addStaticPropToA() {",
            "  A$staticProp = 5;",
            "}",
            "if (A$staticProp) {",
            "  use(A$staticProp);",
            "}"));
  }

  @Test
  public void testEs6ClassStaticInheritance() {
    test("class A {} A.foo = 5; use(A.foo); class B extends A {}",
        "class A {} var A$foo = 5; use(A$foo); class B extends A {}");

    // We potentially collapse unsafely when the subclass accesses a static property on its
    // superclass. However, AggressiveInlineAliases tries to rewrite inherited accesses to make this
    // collapsing safe. See InlineAndCollapsePropertiesTests for examples.
    test(
        "class A {}     A.foo = 5; use(A.foo); class B extends A {} use(B.foo);",
        "class A {} var A$foo = 5; use(A$foo); class B extends A {} use(B.foo);");

    test(
        "class A {}     A.foo = 5; class B extends A {} use(B.foo);     B.foo = 6; use(B.foo);",
        "class A {} var A$foo = 5; class B extends A {} use(B$foo); var B$foo = 6; use(B$foo);");

    testSame(lines(
        "class A {}",
        "/** @nocollapse */",
        "A.foo = 5;",
    "class B extends A {}",
        "use(B.foo);",
        "/** @nocollapse */",
        "B.foo = 6;",
        "use(B.foo);"));
  }

  @Test
  public void testEs6ClassExtendsChildClass() {
    test(
        lines(
            "class Thing {}",
            "Thing.Builder = class {};",
            "class Subthing {}",
            "Subthing.Builder = class extends Thing.Builder {}"),
        lines(
            "class Thing {}",
            "var Thing$Builder = class {};",
            "class Subthing {}",
            "var Subthing$Builder = class extends Thing$Builder {}"));
  }

  @Test
  public void testSuperExtern() {
    testSame(
        lines(
            "class Foo {",
            "  constructor(){",
            "    this.x = x; ",
            "  }",
            "  getX() {",
            "    return this.x;",
            "  }",
            "}",
            "class Bar extends Foo {",
            "  constructor(x, y) {",
            "    super(x);",
            "    this.y = y;",
            "  }",
            "  getX() {",
            "    return super.getX() + this.y;",
            "  }",
            "}",
            "let too = new Bar();",
            "too.getX();"));

  }

  @Test
  public void testPropertyMethodAssignment_unsafeThis() {
    // ES5 version
    setLanguage(LanguageMode.ECMASCRIPT3, LanguageMode.ECMASCRIPT3);
    test(
        lines(
            "var foo = { ",
            "  bar: 1, ",
            "  myFunc: function myFunc() {",
            "    return this.bar",
            "  }",
            "};",
            "foo.myFunc();"),
        lines(
            "var foo$bar = 1;",
            "var foo$myFunc = function myFunc() {",
            "  return this.bar",
            "};",
            "foo$myFunc();"),
        warning(CollapseProperties.UNSAFE_THIS));

    // ES6 version
    setLanguage(LanguageMode.ECMASCRIPT_2015, LanguageMode.ECMASCRIPT_2015);
    test(
        lines(
            "var foo = { ",
            "  bar: 1, ",
            "  myFunc() {",
            "    return this.bar;",
            "  }",
            "};",
            "foo.myFunc();"),
        lines(
            "var foo$bar = 1;",
            "var foo$myFunc = function() {",
            "  return this.bar",
            "};",
            "foo$myFunc();"),
        warning(CollapseProperties.UNSAFE_THIS));

    // "this" is lexically scoped in arrow functions so collapsing is safe.
    test(
        lines(
            "var foo = { ",
            "  myFunc: () => {",
            "    return this;",
            "  }",
            "};",
            "foo.myFunc();"),
        lines(
            "var foo$myFunc = () => {",
            "  return this",
            "};",
            "foo$myFunc();"));
  }

  @Test
  public void testPropertyMethodAssignment_noThis() {
    // ES5 Version
    setLanguage(LanguageMode.ECMASCRIPT3, LanguageMode.ECMASCRIPT3);
    test(
        lines(
            "var foo = { ",
            "  bar: 1, ",
            "  myFunc: function myFunc() {",
            "    return 5",
            "  }",
            "};",
            "foo.myFunc();"),
        lines(
            "var foo$bar = 1;",
            "var foo$myFunc = function myFunc() {",
            "    return 5;",
            "};",
            "foo$myFunc();"));

    // ES6 version
    setLanguage(LanguageMode.ECMASCRIPT_2015, LanguageMode.ECMASCRIPT_2015);
    test(
        lines(
            "var foo = { ",
            "  bar: 1, ",
            "  myFunc() {",
            "    return 5;",
            "  }",
            "};",
            "foo.myFunc();"),
        lines(
            "var foo$bar = 1;",
            "var foo$myFunc = function() {",
            "    return 5;",
            "};",
            "foo$myFunc();"));
  }

  @Test
  public void testMethodPropertyShorthand() {
    test(
        lines(
            "var foo = { ",
            "  bar: 1, ",
            "   myFunc() {",
            "    return 2",
            "  }",
            "};",
            "foo.myFunc();"),
        lines(
            "var foo$bar = 1;",
            "var foo$myFunc = function() {",
            "    return 2;",
            "};",
            "foo$myFunc();"));
  }

  @Test
  public void testLetConstObjectAssignmentProperties() {
    // All qualified names - even for variables that are initially declared as LETS and CONSTS -
    // are being declared as VAR statements, but this is correct because we are only
    // collapsing for global names.

    test(
        "let a = {}; a.b = {}; a.b.c = {}; let d = 1; d = a.b.c;",
        "var a$b$c = {}; let d = 1; d = a$b$c;");

    test("let a = {}; if(1)  { a.b = 1; }",
         "if(1) { var a$b = 1; }");

    testSame("if(1) { let a = {}; a.b = 1; }");

    test(
        "var a = {}; a.b = 1; if(1) { let a = {}; a.b = 2; }",
        "var a$b = 1; if(1) { let a$jscomp$1 = {}; a$jscomp$1.b = 2; }");
  }

  @Test
  public void testTemplateStrings() {
    test(
        lines(
            "var a = {};",
            "a.b = 'foo';",
            "var c = `Hi ${a.b}`;"),
        lines(
            "var a$b = 'foo';",
            "var c = `Hi ${a$b}`;"));
  }

  @Test
  public void testDoesNotCollapseInEs6ModuleScope() {
    testSame("var a = {}; a.b = {}; a.b.c = 5; export default function() {};");

    test(new String[] {
        "import * as a from './a.js'; let b = a.b;",
        "var a = {}; a.b = 5;"
    }, new String[] {
        "import * as a$jscomp$1 from './a.js'; let b = a$jscomp$1.b;",
        "var a$b = 5;"
    });
  }

  @Test
  public void testDefaultParameters() {
    testSame("var a = {b: 5}; function f(x=a) { alert(x.b); }");

    test(
        "var a = {b: {c: 5}}; function f(x=a.b) { alert(x.c); }",
        "var a$b = {c: 5}; function f(x=a$b) { alert(x.c); }");

    test(
        "var a = {b: 5}; function f(x=a.b) { alert(x); }",
        "var a$b = 5; function f(x=a$b) { alert(x); }");
  }

  @Test
  public void testModuleExportsBasicCommonJs() {
    this.setupModuleExportsOnly();

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(SourceFile.fromCode("mod1.js", "module.exports = 123;"));
    inputs.add(SourceFile.fromCode("entry.js", "var mod = require('./mod1.js'); alert(mod);"));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            "/** @const */ var module$mod1={}; /** @const */ var module$mod1$default = 123;"));
    expected.add(
        SourceFile.fromCode(
            "entry.js", "var mod = module$mod1$default; alert(module$mod1$default);"));

    test(inputs, expected);
  }

  @Test
  public void testModuleExportsBasicEsm() {
    this.setupModuleExportsOnly();

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(SourceFile.fromCode("mod1.js", "export default 123; export var bar = 'bar'"));
    inputs.add(
        SourceFile.fromCode(
            "entry.js", "import mod, {bar} from './mod1.js'; alert(mod); alert(bar)"));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            lines(
                "var $jscompDefaultExport$$module$mod1=123;",
                "var bar$$module$mod1 = 'bar';",
                "/** @const */ var module$mod1={};",
                "/** @const */ var module$mod1$bar = bar$$module$mod1",
                "/** @const */ var module$mod1$default = $jscompDefaultExport$$module$mod1;")));
    expected.add(
        SourceFile.fromCode(
            "entry.js", "alert($jscompDefaultExport$$module$mod1); alert(bar$$module$mod1);"));

    test(inputs, expected);
  }

  @Test
  public void testMutableModuleExportsBasicEsm() {
    this.setupModuleExportsOnly();

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(
        SourceFile.fromCode(
            "mod1.js",
            lines(
                "export default 123;", //
                "export var bar = 'ba';",
                "function f() { bar += 'r'; }")));
    inputs.add(
        SourceFile.fromCode(
            "entry.js", "import mod, {bar} from './mod1.js'; alert(mod); alert(bar)"));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            lines(
                "var $jscompDefaultExport$$module$mod1=123;",
                "var bar$$module$mod1 = 'ba';",
                "function f$$module$mod1() { bar$$module$mod1 += 'r'; }",
                "/** @const */ var module$mod1= {",
                "  /** @return {?} */ get bar() { return bar$$module$mod1; },",
                "};",
                "/** @const */ var module$mod1$default = $jscompDefaultExport$$module$mod1;")));
    expected.add(
        SourceFile.fromCode(
            "entry.js",
            lines(
                "alert($jscompDefaultExport$$module$mod1);", //
                "alert(bar$$module$mod1);")));

    test(inputs, expected);
  }

  @Test
  public void testModuleExportsObjectCommonJs() {
    this.setupModuleExportsOnly();

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(
        SourceFile.fromCode(
            "mod1.js",
            LINE_JOINER.join(
                "var foo ={};", "foo.bar = {};", "foo.bar.baz = 123;", "module.exports = foo;")));
    inputs.add(
        SourceFile.fromCode("entry.js", "var mod = require('./mod1.js'); alert(mod.bar.baz);"));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            LINE_JOINER.join(
                "/** @const */ var module$mod1={};",
                " /** @const */ var module$mod1$default = {};",
                "module$mod1$default.bar = {};",
                "module$mod1$default.bar.baz = 123;")));
    expected.add(
        SourceFile.fromCode(
            "entry.js", "var mod = module$mod1$default; alert(module$mod1$default.bar.baz);"));

    test(inputs, expected);
  }

  @Test
  public void testModuleExportsObjectEsm() {
    this.setupModuleExportsOnly();

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(
        SourceFile.fromCode(
            "mod1.js",
            lines(
                "var foo ={};", //
                "foo.bar = {};",
                "foo.bar.baz = 123;",
                "export default foo;")));
    inputs.add(SourceFile.fromCode("entry.js", "import mod from './mod1.js'; alert(mod.bar.baz);"));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            lines(
                "var foo$$module$mod1 = {};",
                "foo$$module$mod1.bar = {};",
                "foo$$module$mod1.bar.baz = 123;",
                "var $jscompDefaultExport$$module$mod1 = foo$$module$mod1;",
                "/** @const */ var module$mod1={};",
                "/** @const */ var module$mod1$default = $jscompDefaultExport$$module$mod1;")));
    expected.add(
        SourceFile.fromCode("entry.js", "alert($jscompDefaultExport$$module$mod1.bar.baz);"));

    test(inputs, expected);
  }

  @Test
  public void testModuleExportsObjectSubPropertyCommonJs() {
    this.setupModuleExportsOnly();

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(
        SourceFile.fromCode(
            "mod1.js",
            LINE_JOINER.join(
                "var foo ={};", "module.exports = foo;", "module.exports.bar = 'bar';")));
    inputs.add(SourceFile.fromCode("entry.js", "var mod = require('./mod1.js'); alert(mod.bar);"));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            LINE_JOINER.join(
                "/** @const */ var module$mod1={};",
                " /** @const */ var module$mod1$default = {};",
                "module$mod1$default.bar = 'bar';")));
    expected.add(
        SourceFile.fromCode(
            "entry.js", "var mod = module$mod1$default; alert(module$mod1$default.bar);"));

    test(inputs, expected);
  }

  @Test
  public void testModuleDynamicImportCommonJs() {
    this.setupModuleExportsOnly();
    this.setWebpackModulesById(
        ImmutableMap.of(
            "1", "mod1.js",
            "2", "entry.js"));
    this.setModuleResolutionMode(ResolutionMode.WEBPACK);
    this.enableDependencyManagement = true;
    this.entryPoints = new ArrayList<>();
    this.entryPoints.add(ModuleIdentifier.forFile("entry.js"));

    ArrayList<SourceFile> inputs = new ArrayList<>();
    inputs.add(SourceFile.fromCode("mod1.js", "module.exports = 123;"));
    inputs.add(
        SourceFile.fromCode(
            "entry.js",
            lines(
                "__webpack_require__.e(1).then(",
                "    function() { return __webpack_require__(1);})")));

    ArrayList<SourceFile> expected = new ArrayList<>();
    expected.add(
        SourceFile.fromCode(
            "mod1.js",
            "/** @const */ var module$mod1={}; /** @const */ module$mod1.default = 123;"));
    expected.add(
        SourceFile.fromCode(
            "entry.js",
            lines(
                "/** @const */ var module$entry={};",
                "__webpack_require__.e(1).then(",
                "    function() { return module$mod1.default;})")));

    test(inputs, expected);
  }
}