Create type masks lazily.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

Index: sdk/lib/_internal/compiler/implementation/resolution/members.dart
diff --git a/sdk/lib/_internal/compiler/implementation/resolution/members.dart b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
index bf5708560af5300a54bd8431d2283ff5765bb882..f0473f440620218f2a72a78ee24764745701a7b5 100644
--- a/sdk/lib/_internal/compiler/implementation/resolution/members.dart
+++ b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
@@ -26,6 +26,14 @@ abstract class TreeElements {
   Selector setMoveNextSelector(ForIn node, Selector selector);
   Selector setCurrentSelector(ForIn node, Selector selector);
 
+  /**
+   * Returns [:true:] if [node] is a type literal.
+   *
+   * Resolution marks this by setting the type on the node to be the
+   * [:Type:] type.
+   */
+  bool isTypeLiteral(Send node);
+
   /// Register additional dependencies required by [currentElement].
   /// For example, elements that are used by a backend.
   void registerDependency(Element element);
@@ -132,6 +140,10 @@ class TreeElementMapping implements TreeElements {
     return selectors[node.inToken];
   }
 
+  bool isTypeLiteral(Send node) {
+    return getType(node) != null;
+  }
+
   void registerDependency(Element element) {
     otherDependencies.add(element.implementation);
   }
@@ -2313,7 +2325,7 @@ class ResolverVisitor extends MappingVisitor<Element> {
         // Set the type of the node to [Type] to mark this send as a
         // type variable expression.
         mapping.setType(node, compiler.typeClass.computeType(compiler));
-        world.registerInstantiatedClass(compiler.typeClass, mapping);
+        world.registerTypeLiteral(target, mapping);
       } else if (target.impliesType() && !sendIsMemberAccess) {
         // Set the type of the node to [Type] to mark this send as a
         // type literal.
@@ -2477,8 +2489,10 @@ class ResolverVisitor extends MappingVisitor<Element> {
       }
       if (identical(source, '++')) {
         registerBinaryOperator(const SourceString('+'));
+        world.registerInstantiatedClass(compiler.intClass, mapping);
       } else if (identical(source, '--')) {
         registerBinaryOperator(const SourceString('-'));
+        world.registerInstantiatedClass(compiler.intClass, mapping);
       } else if (source.endsWith('=')) {
         registerBinaryOperator(Elements.mapToUserOperator(operatorName));
       }