[kernel] Support for top-level generic functions.

pkg/kernel/lib/transformations/closure/context.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 kernel.transformations.closure.context;
 
 import '../../ast.dart'
     show
         Expression,
         NullLiteral,
@@ skipping 111 matching lines @@
         parent,
         converter.rewriter.contextDeclaration,
         converter.rewriter.vectorCreation);
   }
 
   Expression get expression => accessor.buildSimpleRead();
 
   Accessor get accessor => new VariableAccessor(self, null, TreeNode.noOffset);
 
   void extend(VariableDeclaration variable, Expression value) {
-    // Increase index by 1, because the parent occupies item 0, and all other
-    // variables are therefore shifted by 1.
+    // Increase index by 2, because the type arguments vector occupies position
+    // 0, the parent occupies position 1, and all other variables are therefore
+    // shifted by 2.
     VectorSet initializer =
-        new VectorSet(expression, variables.length + 1, value);
+        new VectorSet(expression, variables.length + 2, value);
     value.parent = initializer;
 
     converter.rewriter.insertExtendContext(initializer);
 
     ++vectorCreation.length;
     variables.add(variable);
     initializers[variable] = initializer;
   }
 
   void update(VariableDeclaration variable, Expression value) {
     VectorSet initializer = initializers[variable];
     initializer.value = value;
     value.parent = initializer;
   }
 
   Expression lookup(VariableDeclaration variable) {
     var index = variables.indexOf(variable);
-    // Increase index by 1 in case of success, because the parent occupies
-    // item 0, and all other variables are therefore shifted by 1.
+    // Increase index by 2 in case of success, because the type arguments vector
+    // occupies position 0, the parent occupies position 1, and all other
+    // variables are therefore shifted by 2.
     return index == -1
         ? parent.lookup(variable)
-        : new VectorGet(expression, index + 1);
+        : new VectorGet(expression, index + 2);
   }
 
   Expression assign(VariableDeclaration variable, Expression value,
       {bool voidContext: false}) {
     var index = variables.indexOf(variable);
-    // Increase index by 1 in case of success, because the parent occupies
-    // item 0, and all other variables are therefore shifted by 1.
+    // Increase index by 2 in case of success, because the type arguments vector
+    // occupies position 0, the parent occupies position 1, and all other
+    // variables are therefore shifted by 2.
     return index == -1
         ? parent.assign(variable, value, voidContext: voidContext)
-        : new VectorSet(expression, index + 1, value);
+        : new VectorSet(expression, index + 2, value);
   }
 
   Context toNestedContext([Accessor accessor]) {
     accessor ??= this.accessor;
     List<List<VariableDeclaration>> variabless = <List<VariableDeclaration>>[];
     var current = this;
     while (current != null && current is! NoContext) {
       if (current is LocalContext) {
         variabless.add(current.variables);
         current = current.parent;
@@ skipping 25 matching lines @@
   void extend(VariableDeclaration variable, Expression value) {
     converter.context = new LocalContext(converter, this)
       ..extend(variable, value);
   }
 
   Expression lookup(VariableDeclaration variable) {
     Expression context = expression;
     for (var variables in variabless) {
       var index = variables.indexOf(variable);
       if (index != -1) {
-        // Increase index by 1, because the parent occupies item 0, and all
-        // other variables are therefore shifted by 1.
-        return new VectorGet(context, index + 1);
+        // Increase index by 2 in case of success, because the type arguments
+        // vector occupies position 0, the parent occupies item 1, and all other
+        // variables are therefore shifted by 2.
+        return new VectorGet(context, index + 2);
       }
-      // Item 0 of a context always points to its parent.
-      context = new VectorGet(context, 0);
+      // Item 1 of a context always points to its parent.
+      context = new VectorGet(context, 1);
     }
     throw 'Unbound NestedContext.lookup($variable)';
   }
 
   Expression assign(VariableDeclaration variable, Expression value,
       {bool voidContext: false}) {
     Expression context = expression;
     for (List<VariableDeclaration> variables in variabless) {
       var index = variables.indexOf(variable);
       if (index != -1) {
-        // Increase index by 1, because the parent occupies item 0, and all
-        // other variables are therefore shifted by 1.
-        return new VectorSet(context, index + 1, value);
+        // Increase index by 2 in case of success, because the type arguments
+        // vector occupies position 0, the parent occupies item 1, and all other
+        // variables are therefore shifted by 2.
+        return new VectorSet(context, index + 2, value);
       }
-      // Item 0 of a context always points to its parent.
-      context = new VectorGet(context, 0);
+      // Item 1 of a context always points to its parent.
+      context = new VectorGet(context, 1);
     }
     throw 'Unbound NestedContext.lookup($variable)';
   }
 
   Context toNestedContext([Accessor accessor]) {
     return new NestedContext(converter, accessor ?? this.accessor, variabless);
   }
 }