Check result type of redirecting factory in checked mode.

runtime/vm/flow_graph_builder.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/flow_graph_builder.h"
 
 #include "vm/ast_printer.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
 #include "vm/flags.h"
@@ skipping 588 matching lines @@
                                      eliminated);
   }
   return eliminated;
 }
 
 
 // <Expression> :: Assignable { expr:     <Expression>
 //                              type:     AbstractType
 //                              dst_name: String }
 void EffectGraphVisitor::VisitAssignableNode(AssignableNode* node) {
-  UNREACHABLE();
+  ValueGraphVisitor for_value(owner(), temp_index(), loop_depth());
+  node->expr()->Visit(&for_value);
+  Append(for_value);
+  Definition* checked_value;
+  if (CanSkipTypeCheck(node->expr()->token_pos(),
+                       for_value.value(),
+                       node->type(),
+                       node->dst_name())) {
+    checked_value = for_value.value()->definition();  // No check needed.
+  } else {
+    checked_value = BuildAssertAssignable(node->expr()->token_pos(),
+                                          for_value.value(),
+                                          node->type(),
+                                          node->dst_name());
+  }

[srdjan, 2012/11/13 18:33:35]

Why are you not using BuildAssignableValue as below? Maybe just move the
VisitAssignableNode below to EffectGraphVisitor

[regis, 2012/11/13 18:38:53]

I tried, but it does not get simpler. BuildAssertAssignable would need to return
a definition instead of a value, however, this does not work when the test is
skipped, because returning the definition of the input value breaks invariants.
I'm open to suggestions and I can revisit this cl. 

+  ReturnDefinition(checked_value);
 }
 
 
 void ValueGraphVisitor::VisitAssignableNode(AssignableNode* node) {
   ValueGraphVisitor for_value(owner(), temp_index(), loop_depth());
   node->expr()->Visit(&for_value);
   Append(for_value);
   ReturnValue(BuildAssignableValue(node->expr()->token_pos(),
                                    for_value.value(),
                                    node->type(),
@@ skipping 2327 matching lines @@
   intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, reason) + 1;
   char* chars = Isolate::Current()->current_zone()->Alloc<char>(len);
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart