Remove support for missing part-of tag.

sdk/lib/_internal/compiler/implementation/library_loader.dart

Index: sdk/lib/_internal/compiler/implementation/library_loader.dart
diff --git a/sdk/lib/_internal/compiler/implementation/library_loader.dart b/sdk/lib/_internal/compiler/implementation/library_loader.dart
index 0bcd1a51ca3f377c5f4de13601372de47740c680..95f91c853d699817486096901153aac926361025 100644
--- a/sdk/lib/_internal/compiler/implementation/library_loader.dart
+++ b/sdk/lib/_internal/compiler/implementation/library_loader.dart
@@ -368,17 +368,10 @@ class LibraryLoaderTask extends LibraryLoader {
     compiler.withCurrentElement(unit, () {
       compiler.scanner.scan(unit);
       if (unit.partTag == null) {
-        bool wasDiagnosticEmitted = false;
-        compiler.withCurrentElement(library, () {
-          wasDiagnosticEmitted =
-              compiler.onDeprecatedFeature(part, 'missing part-of tag');
-        });
-        if (wasDiagnosticEmitted) {
-          compiler.reportMessage(
-              compiler.spanFromElement(unit),
-              MessageKind.MISSING_PART_OF_TAG.error(),
-              api.Diagnostic.INFO);
-        }
+        compiler.reportMessage(

[ahe, 2013/08/06 14:22:06]

compiler.reportError(unit, MessageKind.MISSING_PART_OF_TAG);

[Johnni Winther, 2013/08/07 06:00:51]

Done.

+            compiler.spanFromElement(unit),
+            MessageKind.MISSING_PART_OF_TAG.error(),
+            api.Diagnostic.ERROR);
       }
     });
   }