added bool type to named args in lib/io and lib/_internal

sdk/lib/_internal/compiler/implementation/elements/modelx.dart

Index: sdk/lib/_internal/compiler/implementation/elements/modelx.dart
diff --git a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
index 51e0f2177fe0ab0a0f370c80bcb8f3d3d88f33e6..42ef97cbceb929231197e5ab9a94937bf2437550 100644
--- a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
+++ b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
@@ -1889,7 +1889,7 @@ abstract class BaseClassElementX extends ElementX implements ClassElement {
    * origin and in the patch are included.
    */
   void forEachInstanceField(void f(ClassElement enclosingClass, Element field),
-                            {includeSuperAndInjectedMembers: false}) {
+                            {bool includeSuperAndInjectedMembers: false}) {
     // Filters so that [f] is only invoked with instance fields.
     void fieldFilter(ClassElement enclosingClass, Element member) {
       if (member.isInstanceMember() && member.kind == ElementKind.FIELD) {