Fix issue 9744

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
@@ skipping 176 matching lines @@
 //   _MyClass@6b3832b. -> _MyClass
 //   _MyClass@6b3832b.named -> _MyClass.named
 //
 static RawString* IdentifierPrettyName(const String& name) {
   intptr_t len = name.Length();
   intptr_t start = 0;
   intptr_t at_pos = len;   // Position of '@' in the name.
   intptr_t dot_pos = len;  // Position of '.' in the name.
   bool is_setter = false;
 
-  for (int i = 0; i < name.Length(); i++) {
+  if (name.Equals(Symbols::TopLevel())) {
+    // Name of invisible top-level class.
+    return Symbols::Empty().raw();
+  }
+  for (int i = start; i < name.Length(); i++) {
     if (name.CharAt(i) == ':') {
       ASSERT(start == 0);
       if (name.CharAt(0) == 's') {
         is_setter = true;
       }
       start = i + 1;
     } else if (name.CharAt(i) == '@') {
       ASSERT(at_pos == len);
       at_pos = i;
     } else if (name.CharAt(i) == '.') {
@@ skipping 12842 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart