Introduce typed selectors to do better tree shaking based on calls on 'this'. Getters and setters w…

lib/compiler/implementation/elements/elements.dart

Index: lib/compiler/implementation/elements/elements.dart
===================================================================
--- lib/compiler/implementation/elements/elements.dart	(revision 6835)
+++ lib/compiler/implementation/elements/elements.dart	(working copy)
@@ -846,6 +846,19 @@
     return false;
   }
 
+  /**
+   * Returns true if [cls] is a subclass of [this].

[kasperl, 2012/04/23 12:34:45]

Shouldn't this be: if [this] is a subclass of [cls]?

[ahe, 2012/04/23 12:37:53]

Good catch.

[ngeoffray, 2012/04/23 13:48:18]

Done.

+   *
+   * This method is not to be used for checking type hierarchy and

[floitsch, 2012/04/23 13:58:30]

Add explanation why, or contrast to it ("whereas a assignment check would
need..., this function only ...")

[ngeoffray, 2012/04/23 14:09:33]

Done.

+   * assignments.
+   */
+  bool isSubclassOf(ClassElement cls) {
+    for (ClassElement s = superclass; s != null; s = s.superclass) {

[kasperl, 2012/04/23 12:34:45]

It is a bit surprising that you don't start at [this]. Document it or fix it?

[ahe, 2012/04/23 12:37:53]

Good catch.

I think this is a copy-and-paste error that Karl and I caused :-)

[ngeoffray, 2012/04/23 13:48:18]

The method should start at this. Code fixed.

+      if (s === cls) return true;
+    }
+    return false;
+  }
+
   bool isInterface() => false;
   bool isNative() => nativeName != null;
   SourceString nativeName;