syntax_data: {"ast_node_type":"other","tokens":[{"end":51,"kind":"keyword","start":0,"text":"visit::walk_pat(self,"}]}
source_snippet:                         visit::walk_pat(self, pat);
context_before:                             std::mem::replace(&mut self.in_union_destructure, true);
context_after:                         self.in_union_destructure = old_in_union_destructure;