{"ast_node_type":"variable","tokens":[{"end":51,"kind":"keyword","start":0,"text":"let"}]}
                let mut result_span = *concat_span;
                // See https://github.com/rust-lang/rust/blob/b0af276da341/compiler/rustc_expand/src/mbe/transcribe.rs#L724-L726.
                marker(&mut result_span);