syntax_data: {"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"user_tys.variant(adt_def,"}]}
source_snippet:                         user_tys.variant(adt_def, variant_index, subpattern.field);
context_before:                     let subpattern_user_tys =
context_after:                     visit_subpat(self, &subpattern.pattern, &subpattern_user_tys, f);