syntax_data: {"ast_node_type":"other","tokens":[{"end":31,"kind":"keyword","start":0,"text":"Range(Arc<PatRange<'tcx>>),"}]}
source_snippet:     Range(Arc<PatRange<'tcx>>),
context_before:     Constant { value: mir::Const<'tcx> },
context_after:     Slice { len: usize, variable_length: bool },