{"ast_node_type":"variable","tokens":[{"end":98,"kind":"keyword","start":0,"text":"let"}]}
    let mut builder = tt::TopSubtreeBuilder::new(tt::Delimiter::invisible_spanned(ctx.call_site));
    let mut ctx = ExpandCtx { bindings, nesting: Vec::new(), call_site };
    expand_subtree(&mut ctx, template, &mut builder, marker).map(|()| builder.build())