syntax_data: {"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"self.tcx.dcx().emit_err(NotParam"}]}
source_snippet:                 self.tcx.dcx().emit_err(NotParam {
context_before:             Err(NotUniqueParam::NotParam(arg)) => {
context_after:                     arg,