syntax_data: {"ast_node_type":"other","tokens":[{"end":47,"kind":"keyword","start":0,"text":"leaf_bindings:"}]}
source_snippet:     leaf_bindings: &[SubpatternBindings<'tcx>],
context_before:     parents: &[PatternExtraData<'tcx>],
context_after: ) -> Vec<Binding<'tcx>> {