syntax_data: {"ast_node_type":"variable","tokens":[{"end":71,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:                 if let Some(source_map) = &session_globals.source_map {
context_before:             with_session_globals(|session_globals| {
context_after:                     write!(f, "{} ({:?})", source_map.span_to_diagnostic_string(*self), self.ctxt())