syntax_data: {"ast_node_type":"variable","tokens":[{"end":82,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let FnAbi { args, ret, c_variadic, fixed_count, conv, can_unwind } = self;
context_before:     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
context_after:         f.debug_struct("FnAbi")