Handle variable declarations in inferrer

pkg/compiler/lib/src/kernel/indexed.dart

Index: pkg/compiler/lib/src/kernel/indexed.dart
diff --git a/pkg/compiler/lib/src/kernel/indexed.dart b/pkg/compiler/lib/src/kernel/indexed.dart
index ba81fc48c9c0732691ce042c9b4303ccbe8f52c7..bf7be15ed6b0f3c39ccbff1ffcc17c7ba3f886ec 100644
--- a/pkg/compiler/lib/src/kernel/indexed.dart
+++ b/pkg/compiler/lib/src/kernel/indexed.dart
@@ -44,6 +44,10 @@ abstract class IndexedTypedef extends _Indexed implements TypedefEntity {
   int get typedefIndex => _index;
 }
 
+abstract class IndexedLocal extends _Indexed implements Local {
+  int get localIndex => _index;
+}
+
 /// Base implementation for an index based map of entities of type [E].
 abstract class EntityMapBase<E extends _Indexed> {
   List<E> _list = <E>[];