Fix regression in meta-serializing rules

pkg/serialization/lib/src/serialization_rule.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of serialization;
 
 // TODO(alanknight): We should have an example and tests for subclassing
 // serialization rule rather than using the hard-coded ClosureToMap rule. And
 // possibly an abstract superclass that's designed to be subclassed that way.
 /**
@@ skipping 382 matching lines @@
 class MirrorRule extends NamedObjectRule {
   bool appliesTo(object, Writer writer) => object is DeclarationMirror;
   nameFor(DeclarationMirror object, Writer writer) =>
       MirrorSystem.getName(object.qualifiedName);
 
   inflateEssential(state, Reader r) {
     var qualifiedName = r.resolveReference(state.first);
     var lookupFull = r.objectNamed(qualifiedName, (x) => null);
     if (lookupFull != null) return lookupFull;
     var separatorIndex = qualifiedName.lastIndexOf(".");
-    var lib = new Symbol(qualifiedName.substring(0, separatorIndex));
     var type = qualifiedName.substring(separatorIndex + 1);
     var lookup = r.objectNamed(type, (x) => null);
     if (lookup != null) return lookup;
-    var libMirror = currentMirrorSystem().findLibrary(lib).first;
-    return libMirror.classes[new Symbol(type)];
+    var name = qualifiedName.substring(0, separatorIndex);
+    // This is very ugly. The library name for an unnamed library is its URI.
+    // That can't be constructed as a Symbol, so we can't use findLibrary.
+    // So follow one or the other path depending if it has a colon, which we
+    // assume is in any URI and can't be in a Symbol.
+    if (name.contains(":")) {
+      var uri = new Uri(name);
+      var libMirror = currentMirrorSystem().libraries[uri];
+      return libMirror.classes[new Symbol(type)];
+    } else {
+      var symbol = new Symbol(name);
+      var typeSymbol = new Symbol(type);
+      var libMirror = currentMirrorSystem().findLibrary(symbol).firstWhere(
+        (lib) => lib.classes[typeSymbol] != null);
+      return libMirror.classes[typeSymbol];
+    }
   }
 }
 
 /**
  * This provides an abstract superclass for writing your own rules specific to
  * a class. It makes some assumptions about behaviour, and so can have a
  * simpler set of methods that need to be implemented in order to subclass it.
  *
  */
 abstract class CustomRule extends SerializationRule {
@@ skipping 158 matching lines @@
   removeWhere(x) => _throw();
   retainWhere(x) => _throw();
   replaceRange(x, y, z) => _throw();
   getRange(x, y) => _throw();
   setRange(x, y, z, [a = 0]) => _throw();
   setAll(x, y) => _throw();
   removeRange(x, y) => _throw();
   get reversed => _throw();
   void set length(x) => _throw();
 }