syntax_data: {"ast_node_type":"other","tokens":[{"end":62,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if must_err && self.dcx().has_errors().is_none() {
context_before:             // If we should err, make sure we did.
context_after:                 // We have skipped a feature gate, and not run into other errors... reject.