Recognize class declarations in export default in NodeUtil.isClassExp…

…ression.

e.g.
  export default class Foo {}
adds Foo to the module scope, although Foo is not an exported name from the module.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=169153915

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

@@ -3040,7 +3040,7 @@ static boolean isFunctionExpression(Node n) {
    * @return Whether n is a class used within an expression.
    */
   static boolean isClassExpression(Node n) {
-    return n.isClass() && !isStatement(n);
+    return n.isClass() && (!isNamedClass(n) || !isDeclarationParent(n.getParent()));
   }
 
   /**

test/com/google/javascript/jscomp/Es6SyntacticScopeCreatorTest.java

@@ -1084,6 +1084,18 @@ public void testClassExpressionInForLoopInitializer() {
     assertTrue(classScope.isDeclared("Clazz", false));
   }
 
+  public void testClassDeclarationInExportDefault() {
+    String js = "export default class Clazz {}";
+    Node root = getRoot(js);
+    Scope globalScope = scopeCreator.createScope(root, null);
+    assertFalse(globalScope.isDeclared("Clazz", false));
+
+    Node moduleBody = root.getFirstChild();
+    checkState(moduleBody.isModuleBody(), moduleBody);
+    Scope moduleScope = scopeCreator.createScope(moduleBody, globalScope);
+    assertTrue(moduleScope.isDeclared("Clazz", false));
+  }
+
   public void testVarsInModulesNotGlobal() {
     Node root = getRoot("goog.module('example'); var x;");
     Scope globalScope = scopeCreator.createScope(root, null);

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

@@ -654,7 +654,8 @@ public void testMayEffectMutableState() {
   public void testIsFunctionExpression() {
     assertContainsAnonFunc(true, "(function(){})");
     assertContainsAnonFunc(true, "[function a(){}]");
-    assertContainsAnonFunc(false, "{x: function a(){}}");
+    assertContainsAnonFunc(false, "{label: function a(){}}");
+    assertContainsAnonFunc(true, "({x: function a(){}})");
     assertContainsAnonFunc(true, "(function a(){})()");
     assertContainsAnonFunc(true, "x = function a(){};");
     assertContainsAnonFunc(true, "var x = function a(){};");
@@ -681,28 +682,66 @@ public void testIsFunctionExpression() {
   }
 
   private void assertContainsAnonFunc(boolean expected, String js) {
-    Node funcParent = findParentOfFuncDescendant(parse(js));
+    Node funcParent = findParentOfFuncOrClassDescendant(parse(js), Token.FUNCTION);
     assertNotNull("Expected function node in parse tree of: " + js, funcParent);
-    Node funcNode = getFuncChild(funcParent);
+    Node funcNode = getFuncOrClassChild(funcParent, Token.FUNCTION);
     assertEquals(expected, NodeUtil.isFunctionExpression(funcNode));
   }
 
-  private Node findParentOfFuncDescendant(Node n) {
+  public void testIsClassExpression() {
+    assertContainsAnonClass(true, "(class {})");
+    assertContainsAnonClass(true, "[class Clazz {}]");
+    assertContainsAnonClass(false, "{label: class Clazz {}}");
+    assertContainsAnonClass(true, "({x: class Clazz {}})");
+    assertContainsAnonClass(true, "x = class Clazz {};");
+    assertContainsAnonClass(true, "var x = class Clazz {};");
+    assertContainsAnonClass(true, "if (class Clazz {});");
+    assertContainsAnonClass(true, "while (class Clazz {});");
+    assertContainsAnonClass(true, "do; while (class Clazz {});");
+    assertContainsAnonClass(true, "for (class Clazz {};;);");
+    assertContainsAnonClass(true, "for (;class Clazz {};);");
+    assertContainsAnonClass(true, "for (;;class Clazz {});");
+    assertContainsAnonClass(true, "for (p in class Clazz {});");
+    assertContainsAnonClass(true, "with (class Clazz {}) {}");
+    assertContainsAnonClass(false, "class Clazz {}");
+    assertContainsAnonClass(false, "if (x) class Clazz {};");
+    assertContainsAnonClass(false, "if (x) { class Clazz {} }");
+    assertContainsAnonClass(false, "if (x); else class Clazz {};");
+    assertContainsAnonClass(false, "while (x) class Clazz {};");
+    assertContainsAnonClass(false, "do class Clazz {} while (0);");
+    assertContainsAnonClass(false, "for (;;) class Clazz {}");
+    assertContainsAnonClass(false, "for (p in o) class Clazz {};");
+    assertContainsAnonClass(false, "with (x) class Clazz {}");
+    assertContainsAnonClass(true, "export default class {};");
+    assertContainsAnonClass(false, "export default class Clazz {};");
+    assertContainsAnonClass(false, "export class Clazz {};");
+  }
+
+  private void assertContainsAnonClass(boolean expected, String js) {
+    Node classParent = findParentOfFuncOrClassDescendant(parse(js), Token.CLASS);
+    assertNotNull("Expected class node in parse tree of: " + js, classParent);
+    Node classNode = getFuncOrClassChild(classParent, Token.CLASS);
+    assertEquals(expected, NodeUtil.isClassExpression(classNode));
+  }
+
+  private Node findParentOfFuncOrClassDescendant(Node n, Token token) {
+    checkArgument(token.equals(Token.CLASS) || token.equals(Token.FUNCTION));
     for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
-      if (c.isFunction()) {
+      if (c.getToken().equals(token)) {
         return n;
       }
-      Node result = findParentOfFuncDescendant(c);
+      Node result = findParentOfFuncOrClassDescendant(c, token);
       if (result != null) {
         return result;
       }
     }
     return null;
   }
 
-  private Node getFuncChild(Node n) {
+  private Node getFuncOrClassChild(Node n, Token token) {
+    checkArgument(token.equals(Token.CLASS) || token.equals(Token.FUNCTION));
     for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
-      if (c.isFunction()) {
+      if (c.getToken().equals(token)) {
         return c;
       }
     }