Implement type variables in mixin applications.

pkg/front_end/lib/src/fasta/source/source_class_builder.dart

 // Copyright (c) 2016, 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.
 
 library fasta.source_class_builder;
 
 import 'package:kernel/ast.dart' show
     Class,
     Constructor,
     Supertype,
@@ skipping 35 matching lines @@
 
 class SourceClassBuilder extends KernelClassBuilder {
   final Class cls;
 
   final Map<String, Builder> constructors;
 
   final Map<String, Builder> membersInScope;
 
   final List<ConstructorReferenceBuilder> constructorReferences;
 
+  final KernelTypeBuilder mixedInType;
+
   SourceClassBuilder(List<MetadataBuilder> metadata, int modifiers,
       String name, List<TypeVariableBuilder> typeVariables,
-      KernelTypeBuilder supertype, List<KernelTypeBuilder>interfaces,
+      KernelTypeBuilder supertype, List<KernelTypeBuilder> interfaces,
       Map<String, Builder> members, LibraryBuilder parent,
-      this.constructorReferences, int charOffset, [Class cls])
+      this.constructorReferences, int charOffset, [Class cls, this.mixedInType])
       : cls = initializeClass(cls, name, parent, charOffset),
         membersInScope = computeMembersInScope(members),
         constructors = computeConstructors(members),
         super(metadata, modifiers, name, typeVariables, supertype, interfaces,
             members, parent, charOffset);
 
   int resolveTypes(LibraryBuilder library) {
     int count = 0;
     if (typeVariables != null) {
       for (KernelTypeVariableBuilder t in typeVariables) {
@@ skipping 17 matching lines @@
         internalError("Unhandled builder: ${builder.runtimeType}");
       }
     }
     members.forEach((String name, Builder builder) {
       do {
         buildBuilder(builder);
         builder = builder.next;
       } while (builder != null);
     });
     cls.supertype = supertype?.buildSupertype();
+    cls.mixedInType = mixedInType?.buildSupertype();
     // TODO(ahe): If `cls.supertype` is null, and this isn't Object, report a
     // compile-time error.
     cls.isAbstract = isAbstract;
     if (interfaces != null) {
       for (KernelTypeBuilder interface in interfaces) {
         Supertype supertype = interface.buildSupertype();
         if (supertype != null) {
           // TODO(ahe): Report an error if supertype is null.
           cls.implementedTypes.add(supertype);
         }
@@ skipping 28 matching lines @@
 Map<String, Builder> computeConstructors(Map<String, Builder> members) {
   Map<String, Builder> constructors = <String, Builder>{};
   members.forEach((String name, Builder builder) {
     if (builder is ProcedureBuilder &&
         (builder.isConstructor || builder.isFactory)) {
       constructors[name] = builder;
     }
   });
   return constructors;
 }