Parse ! as TyEmpty (except in fn return type)

src/libsyntax/parse/parser.rs

@@ -1399,6 +1399,8 @@ pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
             } else {
                 TyKind::Tup(ts)
             }
+        } else if self.eat(&token::Not) {
+            TyKind::Empty
         } else if self.check(&token::BinOp(token::Star)) {
             // STAR POINTER (bare pointer?)
             self.bump();