Check result type of redirecting factory in checked mode.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
===================================================================
--- runtime/vm/flow_graph_builder.cc	(revision 14858)
+++ runtime/vm/flow_graph_builder.cc	(working copy)
@@ -606,7 +606,22 @@
 //                              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);
 }