Better tracking of provided types at call sites

lib/compiler/implementation/universe.dart

Index: lib/compiler/implementation/universe.dart
diff --git a/lib/compiler/implementation/universe.dart b/lib/compiler/implementation/universe.dart
index a03a61c7295d92f44e19ced9a4a85f67449360d7..c42ecd22b1f19ebf63846b050375d36b20ff176d 100644
--- a/lib/compiler/implementation/universe.dart
+++ b/lib/compiler/implementation/universe.dart
@@ -322,7 +322,26 @@ class Selector implements Hashable {
     return orderedNamedArguments;
   }
 
-  toString() => 'Selector($kind, $name, $argumentCount)';
+  String namedArgumentsToString() {
+    if (namedArgumentCount > 0) {
+      StringBuffer result = new StringBuffer();
+      for (int i = 0; i < namedArgumentCount; i++) {
+        if (i != 0) result.add(', ');
+        result.add(namedArguments[i].slowToString());
+      }
+      return "[$result]";
+    }
+    return '';
+  }
+
+  String toString() {
+    String named = '';
+    String type = '';
+    if (namedArgumentCount > 0) named = ', named=${namedArgumentsToString()}';
+    if (receiverType != null) type = ', type=$receiverType';
+    return 'Selector($kind, ${name.slowToString()}, '
+           'arity=$argumentCount$named$type)';
+  }
 }
 
 class TypedSelector extends Selector {
@@ -387,9 +406,4 @@ class TypedSelector extends Selector {
 
     return false;
   }
-
-  toString() {
-    return 'Selector($kind, "${name.slowToString()}", '
-           '$argumentCount, type=$receiverType)';
-  }
 }