syntax_data: {"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let [pat_field] = &subpatterns[..] else { bug!() };
context_before:                 let PatKind::Variant { ref subpatterns, .. } = pat.kind else { bug!() };
context_after:                 self.check_binding_is_irrefutable(