infer field formal parameter types

pkg/analyzer/lib/src/task/strong_mode.dart

Index: pkg/analyzer/lib/src/task/strong_mode.dart
diff --git a/pkg/analyzer/lib/src/task/strong_mode.dart b/pkg/analyzer/lib/src/task/strong_mode.dart
index 208521f061f47cae0a054108792b76974e723f67..ea3559ded41723b04473d827b2846b5cf84f8a05 100644
--- a/pkg/analyzer/lib/src/task/strong_mode.dart
+++ b/pkg/analyzer/lib/src/task/strong_mode.dart
@@ -263,6 +263,11 @@ class InstanceMemberInferrer {
         classElement.fields.forEach(_inferField);
         classElement.accessors.forEach(_inferExecutable);
         classElement.methods.forEach(_inferExecutable);
+        //
+        // Infer initializing formal parameter types. This must happen after
+        // field types are inferred.
+        //
+        classElement.constructors.forEach(_inferConstructorFieldFormals);
         classElement.hasBeenInferred = true;
       } finally {
         elementsBeingInferred.remove(classElement);
@@ -441,6 +446,21 @@ class InstanceMemberInferrer {
       ExecutableElement element, List<ExecutableElement> elements) {
     return elements.every((e) => e.kind == element.kind);
   }
+
+  void _inferConstructorFieldFormals(ConstructorElement element) {
+    for (ParameterElement p in element.parameters) {
+      if (p is FieldFormalParameterElement) {
+        _inferFieldFormalParameter(p);
+      }
+    }
+  }
+
+  void _inferFieldFormalParameter(FieldFormalParameterElement element) {
+    FieldElement field = element.field;
+    if (field != null && element.hasImplicitType) {
+      (element as FieldFormalParameterElementImpl).type = field.type;
+    }
+  }
 }
 
 /**