Add TypeVariable object on runtime to support reflection on type variables.

sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart

 // Copyright (c) 2012, 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.
 
 part of dart2js.js_emitter;
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
  * in classes) are ignored, since they can be treated as non-class elements.
  *
@@ skipping 29 matching lines @@
   /// type, and return types.
   final List<String> globalMetadata = [];
 
   /// A map used to canonicalize the entries of globalMetadata.
   final Map<String, int> globalMetadataMap = <String, int>{};
 
   // TODO(ngeoffray): remove this field.
   Set<ClassElement> instantiatedClasses;
 
   JavaScriptBackend get backend => compiler.backend;
+  TypeVariableConstantHandler get typeVarHandler => backend.typeVarHandler;
 
   String get _ => space;
   String get space => compiler.enableMinification ? "" : " ";
   String get n => compiler.enableMinification ? "" : "\n";
   String get N => compiler.enableMinification ? "\n" : ";\n";
 
   /**
    * Raw ClassElement symbols occuring in is-checks and type assertions.  If the
    * program contains parameterized checks `x is Set<int>` and
    * `x is Set<String>` then the ClassElement `Set` will occur once in
@@ skipping 1647 matching lines @@
                                           ClassBuilder builder,
                                           CodeBuffer buffer) {
     var metadata = buildMetadataFunction(classElement);
     if (metadata != null) {
       builder.addProperty("@", metadata);
     }
 
     if (backend.isNeededForReflection(classElement)) {
       Link typeVars = classElement.typeVariables;
       List properties = [];
-      for (TypeVariableType typeVar in typeVars) {
-        properties.add(js.string(typeVar.name.slowToString()));
-        properties.add(js.toExpression(reifyType(typeVar.element.bound)));
-      }
+      if (typeVarHandler.typeVars[classElement] != null)

[karlklose, 2013/10/14 10:54:43]

Use a {} block even for one statement unless it is a short return statement.

[ahe, 2013/10/14 13:07:07]

Please keep abstractions in place.

typeVarHandler is an abstraction, but it is broken down when you directly access
the "typeVars" map.

You should have a method like:

typeVarHandler.typeVariablesOf(classElement);

[zarah, 2013/10/15 14:20:02]

Done.

[zarah, 2013/10/15 14:20:02]

Done.

+        properties.addAll(typeVarHandler.typeVars[classElement]
+            .map((s) => js.toExpression(s)));

[ahe, 2013/10/14 13:07:07]

This should probably be:

properties = typeVarHandler.typeVars[classElement].map((s) =>
js.toExpression(s));

[zarah, 2013/10/15 14:20:02]

Done.

 
       ClassElement superclass = classElement.superclass;
       bool hasSuper = superclass != null;
       if ((!properties.isEmpty && !hasSuper) ||
           (hasSuper && superclass.typeVariables != typeVars)) {
         builder.addProperty('<>', new jsAst.ArrayInitializer.from(properties));
       }
     }
     List<CodeBuffer> classBuffers = elementBuffers[classElement];
     if (classBuffers == null) {
@@ skipping 25 matching lines @@
     }
 
     // TODO(ahe): This method (generateClass) should return a jsAst.Expression.
     if (!buffer.isEmpty) {
       buffer.write(',$n$n');
     }
     buffer.write('$className:$_');
     buffer.write(jsAst.prettyPrint(builder.toObjectInitializer(), compiler));
     String reflectionName = getReflectionName(classElement, className);
     if (reflectionName != null) {
-      List<int> interfaces = <int>[];
-      for (DartType interface in classElement.interfaces) {
-        interfaces.add(reifyType(interface));
+      if (!backend.isNeededForReflection(classElement)) {
+        buffer.write(',$n$n"+$reflectionName": 0');
+      } else {
+        List<int> interfaces = <int>[];
+        for (DartType interface in classElement.interfaces) {
+          interfaces.add(reifyType(interface));
+        }
+        buffer.write(',$n$n"+$reflectionName": $interfaces');
       }
-      buffer.write(',$n$n"+$reflectionName": $interfaces');
     }
   }
 
   /// If this is true then we can generate the noSuchMethod handlers at startup
   /// time, instead of them being emitted as part of the Object class.
   bool get generateTrivialNsmHandlers => true;
 
   int _selectorRank(Selector selector) {
     int arity = selector.argumentCount * 3;
     if (selector.isGetter()) return arity + 2;
@@ skipping 1262 matching lines @@
     if (value == null) {
       compiler.reportInternalError(
           annotation, 'Internal error: value is null');
       return -1;
     }
     return addGlobalMetadata(
         jsAst.prettyPrint(constantReference(value), compiler).getText());
   }
 
   int reifyType(DartType type) {
-    // TODO(ahe): Handle type variables correctly instead of using "#".
-    String representation = backend.rti.getTypeRepresentation(type, (_) {});
-    return addGlobalMetadata(representation.replaceAll('#', 'null'));
+    jsAst.Expression representation =
+        backend.rti.getTypeRepresentation(type, (variable) {
+          return js.toExpression(typeVarHandler.reifyTypeVar(variable));
+    });

[ahe, 2013/10/14 13:07:07]

Weird indentation.

[zarah, 2013/10/15 14:20:02]

Done.

+
+    return addGlobalMetadata(
+        jsAst.prettyPrint(representation, compiler).getText());
   }
 
   int reifyName(SourceString name) {
     return addGlobalMetadata('"${name.slowToString()}"');
   }
 
   int addGlobalMetadata(String string) {
     return globalMetadataMap.putIfAbsent(string, () {
       globalMetadata.add(string);
       return globalMetadata.length - 1;
@@ skipping 532 matching lines @@
   }
 
   bool isDeferred(Element element) {
     return compiler.deferredLoadTask.isDeferred(element);
   }
 
   bool get areAnyElementsDeferred {
     return compiler.deferredLoadTask.areAnyElementsDeferred;
   }
 }