fix #214, check type of inferred initializing formal with default value

lib/src/checker/resolver.dart

Index: lib/src/checker/resolver.dart
diff --git a/lib/src/checker/resolver.dart b/lib/src/checker/resolver.dart
index bd080e970ba0fea76194e9e139a008b9a3834bfb..473923ffaaca745e0b549beac3fb48f0852ea117 100644
--- a/lib/src/checker/resolver.dart
+++ b/lib/src/checker/resolver.dart
@@ -330,7 +330,7 @@ class _VarExtractor extends RecursiveAstVisitor {
 /// [LibraryResolverWithInference] above.
 ///
 /// Before inference, this visitor is used to resolve top-levels, classes, and
-/// fields, but nothing withihn method bodies. After inference, this visitor is
+/// fields, but nothing within method bodies. After inference, this visitor is
 /// used again to step into method bodies and complete resolution as a second
 /// phase.
 class RestrictedResolverVisitor extends ResolverVisitor {
@@ -453,6 +453,20 @@ class RestrictedResolverVisitor extends ResolverVisitor {
       return super.visitConstructorDeclaration(node);
     }
   }
+
+  @override
+  visitFieldFormalParameter(FieldFormalParameter node) {
+    // Ensure the field formal parameter's type is updated after inference.
+    // Normally this happens during TypeResolver, but that's before we've done
+    // inference on the field type.

[Jennifer Messerly, 2015/06/10 18:22:19]

Is this running at the right time?

In theory, nothing should depend on the parameter type, right? Except verifying:
1. its use inside the method
2. that calls were passing the correct type

Both of those are handled by our very own CodeChecker.

At least, that's the theory I'm operating under here.

Everything seems to work if I move this code below into StaticTypeAnalyzer, but
it seemed better to do as early as possible, since the
FieldFormalParameterElement is born with the wrong type to begin with.

[Siggi Cherem (dart-lang), 2015/06/10 18:28:30]

sgtm. not sure when analyzer does it, but if element.type here is already
incorrect, it seems appropriate to fix it early.

+    var element = node.element;
+    if (element is FieldFormalParameterElement) {
+      if (element.type.isDynamic) {
+        element.type = element.field.type;
+      }
+    }
+    super.visitFieldFormalParameter(node);
+  }
 }
 
 /// Internal state of the resolver, stored so we can reanalyze portions of the