Support type literals as compile-time constants.

sdk/lib/_internal/compiler/implementation/constants.dart

Index: sdk/lib/_internal/compiler/implementation/constants.dart
diff --git a/sdk/lib/_internal/compiler/implementation/constants.dart b/sdk/lib/_internal/compiler/implementation/constants.dart
index 6e20124983af46d758df100113e5424b07e555a8..99495d6d5d36f635ba37fee64fa5958636fe51d4 100644
--- a/sdk/lib/_internal/compiler/implementation/constants.dart
+++ b/sdk/lib/_internal/compiler/implementation/constants.dart
@@ -16,6 +16,7 @@ abstract class ConstantVisitor<R> {
   R visitList(ListConstant constant);
   R visitMap(MapConstant constant);
   R visitConstructed(ConstructedConstant constant);
+  R visitType(TypeConstant constant);
 }
 
 abstract class Constant {
@@ -42,11 +43,13 @@ abstract class Constant {
   bool isNaN() => false;
   bool isMinusZero() => false;
 
+  bool get isType => false;

[ngeoffray, 2012/11/15 16:07:24]

bool isType() => false and move it to where the other predicates are.

[karlklose, 2012/11/19 15:08:58]

Done.

+
   DartType computeType(Compiler compiler);
 
   List<Constant> getDependencies();
 
-  accept(ConstantVisitor);
+  accept(ConstantVisitor visitor);
 }
 
 class SentinelConstant extends Constant {
@@ -316,11 +319,35 @@ abstract class ObjectConstant extends Constant {
 
   DartType computeType(Compiler compiler) => type;
 
-  // TODO(1603): The class should be marked as abstract, but the VM doesn't
-  // currently allow this.
   int get hashCode;

[floitsch, 2012/11/16 13:53:31]

Remove the hashCode line too.

[karlklose, 2012/11/19 15:08:58]

Done.

 }
 
+class TypeConstant extends Constant {

[ngeoffray, 2012/11/15 16:07:24]

extends ObjectConstant ?

[karlklose, 2012/11/19 15:08:58]

Done.

+  /// The user type that this constant represents.
+  final DartType representedType;
+  /// The type of the constant (currently always [Type]).

[ngeoffray, 2012/11/15 16:07:24]

Should it be something else? Please add a comment.

[karlklose, 2012/11/19 15:08:58]

It could be more specific in the future, but the comment is perhaps misleading.
After extending ObjectConstant, I removed this comment, since it is now clear
how this type is used.

+  final DartType type;
+
+  TypeConstant(this.representedType, this.type);
+
+  bool get isType => true;
+  bool isObject() => true;
+
+  DartType computeType(Compiler compiler) {
+    return compiler.typeClass.computeType(compiler);

[ngeoffray, 2012/11/15 16:07:24]

Remove, it will be inherited with ObjectConstant.

[karlklose, 2012/11/19 15:08:58]

Done.

+  }
+
+  bool operator ==(other) {
+    return other is TypeConstant && representedType == other.representedType;
+  }
+
+  int get hashCode => representedType.hashCode * 13;
+
+  List<Constant> getDependencies() => const <Constant>[];
+
+  accept(ConstantVisitor visitor) => visitor.visitType(this);
+}
+
 class ListConstant extends ObjectConstant {
   final List<Constant> entries;
   final int hashCode;