Retrying r10475 (now with null check):

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
===================================================================
--- runtime/vm/flow_graph_builder.cc	(revision 10477)
+++ runtime/vm/flow_graph_builder.cc	(working copy)
@@ -409,7 +409,7 @@
 
 
 // Returns true if the type check can be skipped, for example, if the
-// destination type is Dynamic or if the static type of the value is a subtype
+// destination type is Dynamic or if the compile type of the value is a subtype
 // of the destination type.
 bool EffectGraphVisitor::CanSkipTypeCheck(intptr_t token_pos,
                                           Value* value,
@@ -441,7 +441,9 @@
     return false;
   }
 
-  const bool eliminated = value->StaticTypeIsMoreSpecificThan(dst_type);
+  // Propagated types are not set yet.
+  // More checks will possibly be eliminated during type propagation.
+  const bool eliminated = value->CompileTypeIsMoreSpecificThan(dst_type);
   if (FLAG_trace_type_check_elimination) {
     FlowGraphPrinter::PrintTypeCheck(owner()->parsed_function(),
                                      token_pos,