Made inline functions compatible with default parameters

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=159463552

src/com/google/javascript/jscomp/DefinitionsRemover.java

@@ -57,8 +57,7 @@ static Definition getDefinition(Node n, boolean isExtern) {
       return new AssignmentDefinition(parent, isExtern);
     } else if (NodeUtil.isObjectLitKey(n)) {
       return new ObjectLiteralPropertyDefinition(parent, n, n.getFirstChild(), isExtern);
-    } else if (NodeUtil.getEnclosingType(n, Token.PARAM_LIST) != null
-        && !n.isParamList() && !n.isRest()) {
+    } else if (NodeUtil.getEnclosingType(n, Token.PARAM_LIST) != null && n.isName()) {
       Node paramList = NodeUtil.getEnclosingType(n, Token.PARAM_LIST);
       Node function = paramList.getParent();
       return new FunctionArgumentDefinition(function, n, isExtern);

src/com/google/javascript/jscomp/FunctionArgumentInjector.java

@@ -42,7 +42,9 @@ class FunctionArgumentInjector {
   // identifier can be used, so we use "this".
   static final String THIS_MARKER = "this";
 
-  static final String REST_MARKER = "REST";
+  static final String REST_MARKER = "rest param";
+
+  static final String DEFAULT_MARKER = "Default Value";
 
   private FunctionArgumentInjector() {
     // A private constructor to prevent instantiation.
@@ -138,15 +140,21 @@ static LinkedHashMap<String, Node> getFunctionCallParameterMap(
             cArg = cArg.getNext();
           }
           argMap.put(fnParam.getFirstChild().getString(), array);
+          return argMap;
+        } else if (fnParam.isDefaultValue()) {
+          argMap.put(fnParam.getFirstChild().getString(), cArg);
         } else {
           argMap.put(fnParam.getString(), cArg);
-          cArg = cArg.getNext();
         }
+        cArg = cArg.getNext();
       } else {
         if (fnParam.isRest()) {
           //No arguments for REST parameters
           Node array = IR.arraylit();
           argMap.put(fnParam.getFirstChild().getString(), array);
+        } else if (fnParam.isDefaultValue()) {
+          Node defaultValue = fnParam.getSecondChild().cloneTree();
+          argMap.put(fnParam.getFirstChild().getString(), defaultValue);
         } else {
           Node srcLocation = callNode;
           argMap.put(fnParam.getString(), NodeUtil.newUndefinedNode(srcLocation));
@@ -158,7 +166,7 @@ static LinkedHashMap<String, Node> getFunctionCallParameterMap(
     // called function.
     while (cArg != null) {
       String uniquePlaceholder =
-        getUniqueAnonymousParameterName(safeNameIdSupplier);
+          getUniqueAnonymousParameterName(safeNameIdSupplier);
       argMap.put(uniquePlaceholder, cArg);
       cArg = cArg.getNext();
     }
@@ -571,6 +579,8 @@ private static Set<String> getFunctionParameterSet(Node fnNode) {
     for (Node n : NodeUtil.getFunctionParameters(fnNode).children()) {
       if (n.isRest()){
         set.add(REST_MARKER);
+      } else if (n.isDefaultValue()){
+        set.add(DEFAULT_MARKER);
       } else {
         set.add(n.getString());
       }

test/com/google/javascript/jscomp/InlineFunctionsTest.java

@@ -2599,4 +2599,96 @@ public void disabled_testRestParam1() {
             "countArgs(1, 1, 1, 1, 1);"),
         "[1, 1, 1, 1, 1].length;");
   }
+
+  public void testDefaultParam1() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = 1) {",
+            "  return a + b;",
+            "}",
+            "foo(1);"),
+        "1+1");
+  }
+
+  public void testDefaultParam2() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = 1) {",
+            "  return a + b;",
+            "}",
+            "foo(1, 2);"),
+        "1+2");
+  }
+
+  public void testDefaultParam3() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a = 1, b = 2) {",
+            "  return a + b;",
+            "}",
+            "foo(3, 4);"),
+        "3+4");
+  }
+
+  public void testDefaultParam4() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = {foo: 5}) {",
+            "  return a + b.foo;",
+            "}",
+            "foo(3, {foo: 9});"),
+        "{ var b$jscomp$inline_1={foo:9}; 3 + b$jscomp$inline_1.foo; }");
+  }
+
+  public void testDefaultParam5() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = {foo: 5, bar: 6}) {",
+            "  return a + b.foo + b.bar;",
+            "}",
+            "foo(3, {foo: 1, bar: 2});"),
+        "{ var b$jscomp$inline_1={foo:1,bar:2};3+b$jscomp$inline_1.foo"
+            + "+b$jscomp$inline_1.bar }");
+  }
+
+  public void testDefaultParam6() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = {foo: 5}) {",
+            "  return a + b.foo;",
+            "}",
+            "foo(3);"),
+        "{ var b$jscomp$inline_1={foo:5};3+b$jscomp$inline_1.foo }");
+  }
+
+  public void testDefaultParam7() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = {foo: 5, bar: 6}) {",
+            "  return a + b.foo + b.bar;",
+            "}",
+            "foo(3, {foo: 1});"),
+        "{ var b$jscomp$inline_1={foo:1};3+b$jscomp$inline_1.foo"
+            + "+b$jscomp$inline_1.bar }");
+  }
+
+  public void testDefaultParam8() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = [1, 2]) {",
+            "  return a + b[1];",
+            "}",
+            "foo(3, [7, 8]);"),
+        "{ var b$jscomp$inline_1=[7,8];3+b$jscomp$inline_1[1] }");
+  }
+
+  public void testDefaultParam9() {
+    test(
+        LINE_JOINER.join(
+            "function foo(a, b = []) {",
+            "  return a + b[1];",
+            "}",
+            "foo(3, [7, 8]);"),
+        "{ var b$jscomp$inline_1=[7,8];3+b$jscomp$inline_1[1] }");
+  }
 }

test/com/google/javascript/jscomp/IntegrationTest.java

@@ -4348,6 +4348,23 @@ public void testInlineRestParam() {
             + "=arguments[a];return b[0]}(8))");
   }
 
+  // TODO(bellashim): Add a non-transpiling version of this test when InlineFunctions
+  // can run in that mode.
+  public void testDefaultParameters() {
+    CompilerOptions options = createCompilerOptions();
+    CompilationLevel.ADVANCED_OPTIMIZATIONS.setOptionsForCompilationLevel(options);
+    options.setLanguageIn(LanguageMode.ECMASCRIPT_2017);
+    options.setLanguageOut(LanguageMode.ECMASCRIPT5);
+
+    test(options,
+        LINE_JOINER.join(
+            "function foo(a, b = {foo: 5}) {",
+            "  return a + b.foo;",
+            "}",
+            "alert(foo(3, {foo: 9}));"),
+        "var a={a:9},a=void 0===a?{a:5}:a;alert(3+a.a)");
+  }
+
   /** Creates a CompilerOptions object with google coding conventions. */
   @Override
   protected CompilerOptions createCompilerOptions() {