Generated constructors should call super(...arguments);

They were using `super.apply(this, arguments)` which is invalid
ES6 syntax.

Also cleans up some obsolete code that was only needed for NTI.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=202377340

src/com/google/javascript/jscomp/Es6ConvertSuper.java

@@ -84,10 +84,11 @@ private void addSyntheticConstructor(Node classNode) {
       // A call to super() shouldn't actually exist for these cases and is problematic to
       // transpile, so don't generate it.
       if (!classNode.isFromExterns()  && !isInterface(classNode)) {
-        Node exprResult = IR.exprResult(IR.call(
-            IR.getprop(IR.superNode(), IR.string("apply")),
-            IR.thisNode(),
-            IR.name("arguments")));
+        // Generate required call to super()
+        // `super(...arguments);`
+        // Note that transpilation of spread args must occur after this pass for this to work.
+        Node exprResult =
+            IR.exprResult(NodeUtil.newCallNode(IR.superNode(), IR.spread(IR.name("arguments"))));
         body.addChildToFront(exprResult);
       }
       Node constructor = IR.function(

src/com/google/javascript/jscomp/Es6ConvertSuperConstructorCalls.java

@@ -276,7 +276,10 @@ private Node createNewSuperCall(String superClassQName, Node superCall) {
       newSuperCall.putBooleanProp(Node.FREE_CALL, false); // callee is now a getprop
       newSuperCall.addChildAfter(IR.thisNode().useSourceInfoFrom(callee), superClassDotCall);
     } else {
-      // super.apply(null|this, ...) -> SuperClass.apply(this, ...)
+      // spread transpilation does
+      // super(...arguments) -> super.apply(null, arguments)
+      // Now we must do
+      // super.apply(null, arguments) -> SuperClass.apply(this, arguments)
       checkState(callee.isGetProp(), callee);
       Node applyNode = checkNotNull(callee.getSecondChild());
       checkState(applyNode.getString().equals("apply"), applyNode);
@@ -286,15 +289,10 @@ private Node createNewSuperCall(String superClassQName, Node superCall) {
       callee.replaceChild(
           superNode,
           NodeUtil.newQName(compiler, superClassQName).useSourceInfoFromForTree(superNode));
-      // super.apply(null, ...) is generated by spread transpilation
-      // super.apply(this, arguments) is used by Es6ConvertSuper in automatically-generated
-      //   constructors.
-      Node nullOrThisNode = superCall.getFirstChild();
-      if (!nullOrThisNode.isThis()) {
-        checkState(nullOrThisNode.isNull(), nullOrThisNode);
-        superCall.removeChild(nullOrThisNode);
-        newSuperCall.addChildToBack(IR.thisNode().useSourceInfoFrom(nullOrThisNode));
-      }
+      Node nullNode = superCall.getFirstChild();
+      checkState(nullNode.isNull(), nullNode);
+      superCall.removeChild(nullNode);
+      newSuperCall.addChildToBack(IR.thisNode().useSourceInfoFrom(nullNode));
     }
     while (superCall.hasChildren()) {
       newSuperCall.addChildToBack(superCall.removeFirstChild());

src/com/google/javascript/jscomp/Es6RewriteClass.java

@@ -44,9 +44,6 @@ public final class Es6RewriteClass implements NodeTraversal.Callback, HotSwapCom
   private static final FeatureSet features =
       FeatureSet.BARE_MINIMUM.with(Feature.CLASSES, Feature.NEW_TARGET);
 
-  // Whether to add $jscomp.inherits(Parent, Child) for each subclass.
-  private final boolean shouldAddInheritsPolyfill;
-
   static final DiagnosticType DYNAMIC_EXTENDS_TYPE = DiagnosticType.error(
       "JSC_DYNAMIC_EXTENDS_TYPE",
       "The class in an extends clause must be a qualified name.");
@@ -63,12 +60,7 @@ public final class Es6RewriteClass implements NodeTraversal.Callback, HotSwapCom
   static final String INHERITS = "$jscomp.inherits";
 
   public Es6RewriteClass(AbstractCompiler compiler) {
-    this(compiler, true);
-  }
-
-  public Es6RewriteClass(AbstractCompiler compiler, boolean shouldAddInheritsPolyfill) {
     this.compiler = compiler;
-    this.shouldAddInheritsPolyfill = shouldAddInheritsPolyfill;
   }
 
   @Override
@@ -224,7 +216,7 @@ private void visitClass(final NodeTraversal t, final Node classNode, final Node
             IR.string(superClassString)),
             metadata.superClassNameNode.getSourceFileName()));
       } else {
-        if (shouldAddInheritsPolyfill && !classNode.isFromExterns()) {
+        if (!classNode.isFromExterns()) {
           Node classNameNode = NodeUtil.newQName(compiler, metadata.fullClassName)
               .useSourceInfoIfMissingFrom(metadata.classNameNode);
           Node superClassNameNode = metadata.superClassNameNode.cloneTree();

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

@@ -266,7 +266,7 @@ protected FeatureSet featureSet() {
       new HotSwapPassFactory("Es6RewriteClass") {
         @Override
         protected HotSwapCompilerPass create(AbstractCompiler compiler) {
-          return new Es6RewriteClass(compiler, true);
+          return new Es6RewriteClass(compiler);
         }
 
         @Override

test/com/google/javascript/jscomp/Es6ConvertSuperTest.java

@@ -425,7 +425,7 @@ public void testSynthesizingConstructorOfDerivedClassInSource() {
                 "",
                 "class B extends A {",
                 "  /** @param {...?} var_args */",
-                "  constructor(var_args) { super.apply(this, arguments); }",
+                "  constructor(var_args) { super(...arguments); }",
                 "}")));
   }
 

test/com/google/javascript/jscomp/Es6RewriteClassTest.java

@@ -28,8 +28,6 @@
 
 public final class Es6RewriteClassTest extends CompilerTestCase {
 
-  private boolean shouldAddInheritsPolyfill;
-
   private static final String EXTERNS_BASE =
       lines(
           "/** @constructor @template T */",
@@ -73,7 +71,6 @@ protected void setUp() throws Exception {
     setAcceptedLanguage(LanguageMode.ECMASCRIPT_2015);
     setLanguageOut(LanguageMode.ECMASCRIPT3);
     enableRunTypeCheckAfterProcessing();
-    shouldAddInheritsPolyfill = true;
   }
 
   protected final PassFactory makePassFactory(
@@ -97,13 +94,15 @@ protected CompilerPass getProcessor(final Compiler compiler) {
     optimizer.addOneTimePass(
         makePassFactory("es6ConvertSuper", new Es6ConvertSuper(compiler)));
     optimizer.addOneTimePass(makePassFactory("es6ExtractClasses", new Es6ExtractClasses(compiler)));
-    optimizer.addOneTimePass(makePassFactory("es6RewriteClass",
-        new Es6RewriteClass(compiler, shouldAddInheritsPolyfill)));
-    if (shouldAddInheritsPolyfill) {
-      optimizer.addOneTimePass(
-          makePassFactory(
-              "Es6ConvertSuperConstructorCalls", new Es6ConvertSuperConstructorCalls(compiler)));
-    }
+    optimizer.addOneTimePass(makePassFactory("es6RewriteClass", new Es6RewriteClass(compiler)));
+    // Automatically generated constructor calls will contain a call to super() using spread.
+    // super(...arguments);
+    // We depend on that getting rewritten before we do the super constructor call rewriting.
+    optimizer.addOneTimePass(
+        makePassFactory("es6RewriteRestAndSpread", new Es6RewriteRestAndSpread(compiler)));
+    optimizer.addOneTimePass(
+        makePassFactory(
+            "Es6ConvertSuperConstructorCalls", new Es6ConvertSuperConstructorCalls(compiler)));
     return optimizer;
   }
 
@@ -622,19 +621,6 @@ public void testExtends() {
             "let C = function(var_args) {};"));
   }
 
-  public void testExtendsWithoutInheritsPolyfill() {
-    shouldAddInheritsPolyfill = false;
-    test("class D {} class C extends D {}",
-        lines(
-            "/** @constructor @struct */",
-            "let D = function() {};",
-            "/** @constructor @struct",
-            " * @extends {D}",
-            " * @param {...?} var_args",
-            " */",
-            "let C = function(var_args) {super.apply(this,arguments); };"));
-  }
-
   public void testExtendNonNativeError() {
     test(
         lines(

test/com/google/javascript/jscomp/Es6ToEs3ConverterTest.java

@@ -128,6 +128,11 @@ protected CompilerPass getProcessor(final Compiler compiler) {
     optimizer.addOneTimePass(makePassFactory("es6RewriteClass", new Es6RewriteClass(compiler)));
     optimizer.addOneTimePass(
         makePassFactory("es6InjectRuntimeLibraries", new Es6InjectRuntimeLibraries(compiler)));
+    // Automatically generated constructor calls will contain a call to super() using spread.
+    // super(...arguments);
+    // We depend on that getting rewritten before we do the super constructor call rewriting.
+    optimizer.addOneTimePass(
+        makePassFactory("es6RewriteRestAndSpread", new Es6RewriteRestAndSpread(compiler)));
     optimizer.addOneTimePass(
         makePassFactory("convertEs6Late", new LateEs6ToEs3Converter(compiler)));
     optimizer.addOneTimePass(makePassFactory("es6ForOf", new Es6ForOfConverter(compiler)));
@@ -151,7 +156,7 @@ public void testObjectLiteralStringKeysWithNoValue() {
   }
 
   public void testSpreadLibInjection() {
-    testSame("var x = [...a];");
+    test("var x = [...a];", "var x=[].concat($jscomp.arrayFromIterable(a))");
     assertThat(getLastCompiler().injected).containsExactly("es6/util/arrayfromiterable");
   }