simplify constructors, fixes #564

tool/input_sdk/private/ddc_runtime/classes.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// This library defines the operations that define and manipulate Dart
 /// classes.  Included in this are:
 ///   - Generics
 ///   - Class metadata
 ///   - Extension methods
 ///
 
 // TODO(leafp): Consider splitting some of this out.
 part of dart._runtime;
 
 ///
 /// Returns a new type that mixes members from base and all mixins.
 ///
 /// Each mixin applies in sequence, with further to the right ones overriding
 /// previous entries.
 ///
 /// For each mixin, we only take its own properties, not anything from its
 /// superclass (prototype).
 ///
 mixin(base, @rest mixins) => JS('', '''(() => {
   // Create an initializer for the mixin, so when derived constructor calls
   // super, we can correctly initialize base and mixins.
 
   // Create a class that will hold all of the mixin methods.
-  class Mixin extends $base {
-    // Initializer method: run mixin initializers, then the base.
-    [$base.name](...args) {
-      // Run mixin initializers. They cannot have arguments.
-      // Run them backwards so most-derived mixin is initialized first.
-      for (let i = $mixins.length - 1; i >= 0; i--) {
-        let mixin = $mixins[i];
-        let init = mixin.prototype[mixin.name];
-        if (init) init.call(this);
-      }
-      // Run base initializer.
-      let init = $base.prototype[base.name];
-      if (init) init.apply(this, args);
-    }
-  }
+  class Mixin extends $base {}
   // Copy each mixin's methods, with later ones overwriting earlier entries.
   for (let m of $mixins) {
     $copyProperties(Mixin.prototype, m.prototype);
   }
+  // Initializer method: run mixin initializers, then the base.
+  Mixin.prototype.new = function(...args) {
+    // Run mixin initializers. They cannot have arguments.
+    // Run them backwards so most-derived mixin is initialized first.
+    for (let i = $mixins.length - 1; i >= 0; i--) {
+      $mixins[i].prototype.new.call(this);
+    }
+    // Run base initializer.
+    $base.prototype.new.apply(this, args);
+  };
 
   // Set the signature of the Mixin class to be the composition
   // of the signatures of the mixins.
   $setSignature(Mixin, {
     methods: () => {
       let s = {};
       for (let m of $mixins) {
         $copyProperties(s, m[$_methodSig]);
       }
       return s;
@@ skipping 363 matching lines @@
 })()''');
 
 /// Sets the element type of a list literal.
 list(obj, elementType) =>
     JS('', '$setType($obj, ${getGenericClass(JSArray)}($elementType))');
 
 setBaseClass(derived, base) => JS('', '''(() => {
   // Link the extension to the type it's extending as a base class.
   $derived.prototype.__proto__ = $base.prototype;
 })()''');