Make ClassFinalizer indifferent on whether we are generating a snapshot or not.

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 4349 matching lines @@
     const Script& script = Script::Handle(this->script());
     signature_class = Class::NewSignatureClass(signature,
                                                closure_function,
                                                script);
     library.AddClass(signature_class);
   } else {
     closure_function.set_signature_class(signature_class);
   }
   const Type& signature_type = Type::Handle(signature_class.SignatureType());
   if (!signature_type.IsFinalized()) {
-    ClassFinalizer::FinalizeType(
+    // No additional malformed types can be detected during finalization.
+    ClassFinalizer class_finalizer(ClassFinalizer::kNotGeneratingSnapshot);
+    class_finalizer.FinalizeType(
         signature_class, signature_type, ClassFinalizer::kCanonicalize);
   }
   ASSERT(closure_function.signature_class() == signature_class.raw());
   set_implicit_closure_function(closure_function);
   ASSERT(closure_function.IsImplicitClosureFunction());
   return closure_function.raw();
 }
 
 
 RawString* Function::BuildSignature(
@@ skipping 1885 matching lines @@
     if (lib_url.Equals(url)) {
       return lib.raw();
     }
   }
   return Library::null();
 }
 
 
 RawError* Library::Patch(const Script& script) const {
   ASSERT(script.kind() == RawScript::kPatchTag);
-  return Compiler::Compile(*this, script);
+  // Do not tolerate malformed types when patching libraries.
+  return Compiler::Compile(*this, script, ClassFinalizer::kGeneratingSnapshot);
 }
 
 
 bool Library::IsKeyUsed(intptr_t key) {
   intptr_t lib_key;
   const GrowableObjectArray& libs = GrowableObjectArray::Handle(
       Isolate::Current()->object_store()->libraries());
   Library& lib = Library::Handle();
   String& lib_url = String::Handle();
   for (int i = 0; i < libs.Length(); i++) {
@@ skipping 4855 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "WeakProperty";
 }
 
 }  // namespace dart