Implement dyn Trait syntax

src/libsyntax/ast.rs

@@ -1419,7 +1419,7 @@ pub enum TyKind {
     Path(Option<QSelf>, Path),
     /// A trait object type `Bound1 + Bound2 + Bound3`
     /// where `Bound` is a trait or a lifetime.
-    TraitObject(TyParamBounds),
+    TraitObject(TyParamBounds, TraitObjectSyntax),
     /// An `impl Bound1 + Bound2 + Bound3` type
     /// where `Bound` is a trait or a lifetime.
     ImplTrait(TyParamBounds),
@@ -1438,6 +1438,13 @@ pub enum TyKind {
     Err,
 }
 
+/// Syntax used to declare a trait object.
+#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+pub enum TraitObjectSyntax {
+    Dyn,
+    None,
+}
+
 /// Inline assembly dialect.
 ///
 /// E.g. `"intel"` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")``