Improve tracking of the type of fields after object construction

lib/compiler/implementation/ssa/codegen.dart

Index: lib/compiler/implementation/ssa/codegen.dart
diff --git a/lib/compiler/implementation/ssa/codegen.dart b/lib/compiler/implementation/ssa/codegen.dart
index 85382d96fa9aee8420ab31baf8cedf13c6cda73c..81ad82161bd254971a66c369381e174596810a63 100644
--- a/lib/compiler/implementation/ssa/codegen.dart
+++ b/lib/compiler/implementation/ssa/codegen.dart
@@ -1723,6 +1723,13 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
   }
 
   visitFieldSet(HFieldSet node) {
+    if (work.element.isGenerativeConstructorBody() &&
+        node.element.enclosingElement.isClass() &&
+        node.value.hasGuaranteedType() &&
+        node.block.dominates(currentGraph.exit)) {

[ngeoffray, 2012/07/09 21:17:41]

We should probably have a helper method for this instead. Something like
HBasicBlock.isAlwaysExecuted.

+      backend.updateFieldConstructorSetters(node.element,
+                                            node.value.guaranteedType);
+    }
     String name = compiler.namer.getName(node.element);
     beginExpression(JSPrecedence.ASSIGNMENT_PRECEDENCE);
     use(node.receiver, JSPrecedence.MEMBER_PRECEDENCE);