Precompilation:

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/cpu.h"
@@ skipping 8965 matching lines @@
     return Symbols::Empty().raw();
   }
 }
 
 
 RawString* Script::GetSnippet(intptr_t from_line,
                               intptr_t from_column,
                               intptr_t to_line,
                               intptr_t to_column) const {
   const String& src = String::Handle(Source());
+  if (src.IsNull()) {
+    ASSERT(Dart::IsRunningPrecompiledCode());
+    return Symbols::OptimizedOut().raw();
+  }
   intptr_t length = src.Length();
   intptr_t line = 1 + line_offset();
   intptr_t column = 1;
   intptr_t scan_position = 0;
   intptr_t snippet_start = -1;
   intptr_t snippet_end = -1;
   if (from_line - line_offset() == 1) {
     column += col_offset();
   }
 
@@ skipping 12923 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart