syntax_data: {"ast_node_type":"variable","tokens":[{"end":39,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let span = |lo: usize, hi: usize| {
context_before: fn test_trim() {
context_after:         Span::new(BytePos::from_usize(lo), BytePos::from_usize(hi), SyntaxContext::root(), None)