Move definition of Feature next to definitions of WorldImpact and Use

pkg/compiler/lib/src/universe/world_impact.dart

Index: pkg/compiler/lib/src/universe/world_impact.dart
diff --git a/pkg/compiler/lib/src/universe/world_impact.dart b/pkg/compiler/lib/src/universe/world_impact.dart
index 1ba0ab740c3690b9886b0bf9c0c7bb48fad8bba5..ff07fc08bc9d7e7a17db020403c79e51e8c7b1fd 100644
--- a/pkg/compiler/lib/src/universe/world_impact.dart
+++ b/pkg/compiler/lib/src/universe/world_impact.dart
@@ -8,6 +8,17 @@ import '../elements/elements.dart' show Element;
 import '../util/util.dart' show Setlet;
 import 'use.dart' show DynamicUse, StaticUse, TypeUse;
 
+/// Describes of how an element (e.g. a method) impacts the closed-world

[Harry Terkelsen, 2016/08/16 19:36:13]

Either delete "of" or change Describes to Description

[Siggi Cherem (dart-lang), 2016/08/16 19:43:30]

Done.

+/// semantics of a program.
+///
+/// A [WorldImpact] contains information about how a program element affects our
+/// understanding of what's live in a program. For example, it can indicate
+/// that a method uses certain feature, or allocates a specific type.

[Harry Terkelsen, 2016/08/16 19:36:13]

"uses a certain feature"

[Siggi Cherem (dart-lang), 2016/08/16 19:43:30]

Done.

+///
+/// The impact object can be computed locally by inspecting just the resolution
+/// information of that element alone. The compiler uses [Universe] and
+/// [ClassWorld] to combine the information discoverred in the impact objects of

[Harry Terkelsen, 2016/08/16 19:36:13]

discovered

[Siggi Cherem (dart-lang), 2016/08/16 19:43:30]

Done.

+/// all elements reachable in an application.
 class WorldImpact {
   const WorldImpact();