[kernel] Support for top-level generic functions.

pkg/kernel/lib/transformations/closure/rewriter.dart

 // Copyright (c) 2017, 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 kernel.transformations.closure.rewriter;
 
 import '../../ast.dart';
 import 'converter.dart' show ClosureConverter;
 
 /// Used by the [Context] to initialize and update the context variable
@@ skipping 12 matching lines @@
   /// Inserts an allocation of a context and initializes [contextDeclaration]
   /// and [vectorCreation].
   void insertContextDeclaration(Expression accessParent);
 
   /// Inserts an expression or statement that extends the context.
   void insertExtendContext(VectorSet extender);
 
   void _createDeclaration() {
     assert(contextDeclaration == null && vectorCreation == null);
 
-    // Context size is set to 1 initially, because the 0-th element of it works
-    // as a link to the parent context.
-    vectorCreation = new VectorCreation(1);
+    // Context size is set to 2 initially, because the 0-th element of it holds
+    // the vector of type arguments that the VM creates, and the 1-st element
+    // works as a link to the parent context.
+    vectorCreation = new VectorCreation(2);
     contextDeclaration = new VariableDeclaration.forValue(vectorCreation,
         type: new VectorType());
     contextDeclaration.name = "#context";
   }
 }
 
 /// Adds a local variable for the context and adds update [Statement]s to the
 /// current block.
 class BlockRewriter extends AstRewriter {
   Block _currentBlock;
@@ skipping 21 matching lines @@
 
   void _insertStatement(Statement statement) {
     _currentBlock.statements.insert(_insertionIndex++, statement);
     statement.parent = _currentBlock;
   }
 
   void insertContextDeclaration(Expression accessParent) {
     _createDeclaration();
     _insertStatement(contextDeclaration);
     if (accessParent is! NullLiteral) {
-      // Index 0 of a context always points to the parent.
+      // Index 1 of a context always points to the parent.
       _insertStatement(new ExpressionStatement(
-          new VectorSet(new VariableGet(contextDeclaration), 0, accessParent)));
+          new VectorSet(new VariableGet(contextDeclaration), 1, accessParent)));
     }
   }
 
   void insertExtendContext(VectorSet extender) {
     _insertStatement(new ExpressionStatement(extender));
   }
 }
 
 class InitializerListRewriter extends AstRewriter {
   final Constructor parentConstructor;
@@ skipping 15 matching lines @@
   }
 
   @override
   void insertExtendContext(VectorSet extender) {
     var init = new LocalInitializer(
         new VariableDeclaration(null, initializer: extender));
     init.parent = parentConstructor;
     prefix.add(init);
   }
 }