syntax_data: {"ast_node_type":"other","tokens":[{"end":92,"kind":"keyword","start":0,"text":"cx.field_match_pairs(&mut"}]}
source_snippet:                 cx.field_match_pairs(&mut subpairs, extra_data, place_builder, subpatterns);
context_before:             PatKind::Leaf { ref subpatterns } => {
context_after:                 None