syntax_data: {"ast_node_type":"variable","tokens":[{"end":22,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let discr_masked =
context_before:     let mask = discr.size.unsigned_int_max();
context_after:         local_decls.push(LocalDecl::with_source_info(tcx.types.u128, source_info)).into();