syntax_data: {"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if let Some((var_span, read)) = mspans.get_mut(&span) {
context_before:         if let Some(mut mspans) = self.0.try_write() {
context_after:                 *read = true;