Use entities in impact transformers.

pkg/compiler/lib/src/universe/resolution_world_builder.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.
 
 part of world_builder;
 
 abstract class ResolutionWorldBuilder implements WorldBuilder, OpenWorld {
   /// Set of all local functions in the program. Used by the mirror tracking
   /// system to find all live closure instances.
   Iterable<Local> get localFunctions;
@@ skipping 547 matching lines @@
 
   void registerIsCheck(DartType type) {
     isChecks.add(type);
   }
 
   bool registerConstantUse(ConstantUse use) {
     return _constantValues.add(use.value);
   }
 
   void registerStaticUse(StaticUse staticUse, MemberUsedCallback memberUsed) {
+    if (staticUse.kind == StaticUseKind.CLOSURE) {
+      Local localFunction = staticUse.element;
+      FunctionType type =
+          _elementEnvironment.getLocalFunctionType(localFunction);
+      if (type.containsTypeVariables) {
+        localFunctionsWithFreeTypeVariables.add(localFunction);
+      }
+      localFunctions.add(staticUse.element);
+      return;
+    }
+
     MemberEntity element = staticUse.element;
     _StaticMemberUsage usage = _staticMemberUsage.putIfAbsent(element, () {
       if ((element.isStatic || element.isTopLevel) && element.isFunction) {
         return new _StaticFunctionUsage(element);
       } else {
         return new _GeneralStaticMemberUsage(element);
       }
     });
     EnumSet<MemberUse> useSet = new EnumSet<MemberUse>();
 
     if ((element.isStatic || element.isTopLevel) && element.isField) {
       allReferencedStaticFields.add(staticUse.element);
     }
     // TODO(johnniwinther): Avoid this. Currently [FIELD_GET] and
     // [FIELD_SET] contains [BoxFieldElement]s which we cannot enqueue.
     // Also [CLOSURE] contains [LocalFunctionElement] which we cannot
     // enqueue.
     switch (staticUse.kind) {
       case StaticUseKind.FIELD_GET:
         break;
       case StaticUseKind.FIELD_SET:
         fieldSetters.add(staticUse.element);
         break;
       case StaticUseKind.CLOSURE:
-        throw new UnimplementedError(
-            "registerStaticUse not implemented for StaticUseKind.CLOSURE.");
+        // Already handled above.
+        break;
       case StaticUseKind.SUPER_TEAR_OFF:
         useSet.addAll(usage.tearOff());
         methodsNeedingSuperGetter.add(staticUse.element);
         break;
       case StaticUseKind.SUPER_FIELD_SET:
         fieldSetters.add(staticUse.element);
         useSet.addAll(usage.normalUse());
         break;
       case StaticUseKind.STATIC_TEAR_OFF:
         useSet.addAll(usage.tearOff());
@@ skipping 157 matching lines @@
   @override
   bool isMemberUsed(MemberEntity member) {
     if (member.isInstanceMember) {
       _MemberUsage usage = _instanceMemberUsage[member];
       if (usage != null && usage.hasUse) return true;
     }
     _StaticMemberUsage usage = _staticMemberUsage[member];
     return usage != null && usage.hasUse;
   }
 }