Attach TokenStream to ast::Ty

A `Ty` does not have outer attributes, so we only capture tokens
when parsing a `macro_rules!` matcher

compiler/rustc_builtin_macros/src/concat_idents.rs

@@ -61,6 +61,7 @@ pub fn expand_concat_idents<'cx>(
                 id: ast::DUMMY_NODE_ID,
                 kind: ast::TyKind::Path(None, ast::Path::from_ident(self.ident)),
                 span: self.ident.span,
+                tokens: None,
             }))
         }
     }