message: [lang] Fix renaming bug
diff: use crate::contract_gen_impl2;
  use proc_macro2::TokenStream as TokenStream2;
  -pub fn assert_eq_tokenstreams(input: TokenStream, expected: TokenStream) {
  +pub fn assert_eq_tokenstreams(input: TokenStream2, expected: TokenStream2) {
  assert_eq!(
  contract_gen_impl2(input)
  .map(|result| result.to_string())
  @@ -26,7 +26,7 @@ pub fn assert_eq_tokenstreams(input: TokenStream, expected: TokenStream) {
  )
  }
  -pub fn assert_failure(input: TokenStream, err_str: &'static str) {
  +pub fn assert_failure(input: TokenStream2, err_str: &'static str) {
  assert_eq!(
  contract_gen_impl2(input)
  .map(|result| result.to_string())
  