816             FnArg::Receiver(receiver) => Some(receiver),  in receiver()
988                 Some(item_use) => Ok(Item::Use(item_use)),  in parse_rest_of_item()
1034             let value = if let Some(eq_token) = input.parse::<Option<Token![=]>>()? {  in parse_rest_of_item()
1036                 Some((eq_token, expr))  in parse_rest_of_item()
1043                 Some((eq_token, expr))  in parse_rest_of_item()
1070                 if let Some(item) = parse_impl(input, allow_verbatim_impl)? {  in parse_rest_of_item()
1100             if let Some(item) = parse_impl(input, allow_verbatim_impl)? {  in parse_rest_of_item()
1228             if let Some(eq_token) = eq_token {  in parse_optional_definition()
1230                 Ok(Some((eq_token, definition)))  in parse_optional_definition()
1244                 input.call(Ident::parse_any).map(Some)  in parse()
1250                 Some(input.parse()?)  in parse()
1314                         Some((as_token, rename))  in parse()
1344             Some(tree) => tree,  in parse_item_use()
1348         Ok(Some(ItemUse {  in parse_item_use()
1379                 Ok(Some(UseTree::Path(UsePath {  in parse_use_tree()
1385                 Ok(Some(UseTree::Rename(UseRename {  in parse_use_tree()
1399                 Ok(Some(UseTree::Name(UseName { ident })))  in parse_use_tree()
1402             Ok(Some(UseTree::Glob(UseGlob {  in parse_use_tree()
1421                     Some(tree) if !has_any_crate_root_in_path => items.push_value(tree),  in parse_use_tree()
1435                 Ok(Some(UseTree::Group(UseGroup { brace_token, items })))  in parse_use_tree()
1540             Some(Signature {  in parse_signature()
1634             if let Some(dots) = input.parse::<Option<Token![...]>>()? {  in parse_fn_arg_or_variadic()
1637                     pat: Some((pat, colon_token)),  in parse_fn_arg_or_variadic()
1658                 Some((ampersand, lifetime))  in parse()
1676                 if let Some((ampersand, lifetime)) = reference.as_ref() {  in parse()
1707             if let Some(dots) = input.parse::<Option<Token![...]>>()? {  in parse_fn_args()
1708                 variadic = Some(Variadic {  in parse_fn_args()
1715                         Some(input.parse()?)  in parse_fn_args()
1725                     variadic = Some(Variadic {  in parse_fn_args()
1729                             Some(input.parse()?)  in parse_fn_args()
1788                     semi: Some(input.parse()?),  in parse()
1806                     content: Some((brace_token, items)),  in parse()
1862                     Some(input.parse()?)  in parse()
2028                 Some(input.parse()?)  in parse()
2076             Some(ty) if colon_token.is_none() => ty,  in parse_item_type()
2352                     let default = if let Some(eq_token) = input.parse::<Option<Token![=]>>()? {  in parse()
2354                         Some((eq_token, expr))  in parse()
2434                 Some((eq_token, default))  in parse()
2465                 (Some(brace_token), stmts, None)  in parse()
2468                 (None, Vec::new(), Some(semi_token))  in parse()
2547                 Some(input.parse()?)  in parse()
2587             Some(input.parse::<Token![!]>()?)  in parse_impl()
2610                     trait_ = Some((polarity, path, for_token));  in parse_impl()
2623         } else if let Some(polarity) = polarity {  in parse_impl()
2647             Ok(Some(ItemImpl {  in parse_impl()
2673                 Some(defaultness)  in parse()
2681                 if let Some(item) = parse_impl_item_fn(input, allow_omitted_body)? {  in parse()
2698                 let value = if let Some(eq_token) = input.parse::<Option<Token![=]>>()? {  in parse()
2700                     Some((eq_token, expr))  in parse()
2707                     Some((eq_token, expr))  in parse()
2826         Ok(Some(ImplItemFn {  in parse_impl_item_fn()
2880             Some(ty) if colon_token.is_none() => ty,  in parse_impl_item_type()
2905                 Some(input.parse()?)  in parse()
2961             if let Some((as_token, rename)) = &self.rename {  in to_tokens()
3033             if let Some((brace, items)) = &self.content {  in to_tokens()
3171             if let Some((polarity, path, for_token)) = &self.trait_ {  in to_tokens()
3256             if let Some((eq_token, default)) = &self.default {  in to_tokens()
3270                 Some(block) => {  in to_tokens()
3294             if let Some((eq_token, default)) = &self.default {  in to_tokens()
3425                 if let Some(variadic) = &self.variadic {  in to_tokens()
3441             if let Some((ampersand, lifetime)) = &self.reference {  in to_tokens()
3447             if let Some(colon_token) = &self.colon_token {  in to_tokens()
3452                     (Some(_), mutability, Type::Reference(ty)) => {  in to_tokens()
3474             if let Some((pat, colon)) = &self.pat {  in to_tokens()