syntax_data: {"ast_node_type":"variable","tokens":[{"end":23,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let tcx = cx.tcx();
context_before: ) -> Result<&'tcx FnAbi<'tcx, Ty<'tcx>>, &'tcx FnAbiError<'tcx>> {
context_after:     let (caller_location, determined_fn_def_id, is_virtual_call) = if let Some(instance) = instance