Fix some issues in element serialization.

pkg/compiler/lib/src/elements/common.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.
 
 /// Mixins that implement convenience methods on [Element] subclasses.
 
 library elements.common;
 
 import '../common/names.dart' show Names, Uris;
 import '../core_types.dart' show CoreClasses;
@@ skipping 70 matching lines @@
   @override
   bool get isMalformed => false;
 
   @override
   bool get isWarnOnUse => kind == ElementKind.WARN_ON_USE;
 
   @override
   bool get impliesType => (kind.category & ElementCategory.IMPLIES_TYPE) != 0;
 
   @override
+  bool get isAssignable {
+    if (isFinal || isConst) return false;
+    if (isFunction || isConstructor) return false;
+    return true;
+  }
+
+  @override
   Element get declaration => this;
 
   @override
   Element get implementation => this;
 
   @override
   bool get isDeclaration => true;
 
   @override
   bool get isPatched => false;
@@ skipping 22 matching lines @@
     ClassElement cls;
     for (Element e = this; e != null; e = e.enclosingElement) {
       if (e.isClass) {
         // Record [e] instead of returning it directly. We need the last class
         // in the chain since the first classes might be closure classes.
         cls = e.declaration;
       }
     }
     return cls;
   }
+
+  @override
+  Element get outermostEnclosingMemberOrTopLevel {
+    // TODO(lrn): Why is this called "Outermost"?
+    // TODO(johnniwinther): Clean up this method: This method does not return
+    // the outermost for elements in closure classses, but some call-sites rely
+    // on that behavior.
+    for (Element e = this; e != null; e = e.enclosingElement) {
+      if (e.isClassMember || e.isTopLevel) {
+        return e;
+      }
+    }
+    return null;
+  }
 }
 
 abstract class LibraryElementCommon implements LibraryElement {
   @override
   bool get isDartCore => canonicalUri == Uris.dart_core;
 
   @override
   bool get isPlatformLibrary => canonicalUri.scheme == 'dart';
 
   @override
@@ skipping 305 matching lines @@
 
 abstract class FunctionSignatureCommon implements FunctionSignature {
   void forEachRequiredParameter(void function(Element parameter)) {
     requiredParameters.forEach(function);
   }
 
   void forEachOptionalParameter(void function(Element parameter)) {
     optionalParameters.forEach(function);
   }
 
-  Element get firstOptionalParameter => optionalParameters.first;
-
   void forEachParameter(void function(Element parameter)) {
     forEachRequiredParameter(function);
     forEachOptionalParameter(function);
   }
 
   void orderedForEachParameter(void function(Element parameter)) {
     forEachRequiredParameter(function);
     orderedOptionalParameters.forEach(function);
   }
 
@@ skipping 61 matching lines @@
 
   @override
   void forEachLocalMember(void f(Element member)) {
     constructors.forEach(f);
     if (mixin != null)
       mixin.forEachLocalMember((Element mixedInElement) {
       if (mixedInElement.isInstanceMember) f(mixedInElement);
     });
   }
 }