Ast.Pattern (head, hrefs, vars), term ->
Ast.Pattern (head, k_xref hrefs, List.map aux_capture_variable vars), k term
| Ast.Wildcard, term -> Ast.Wildcard, k term
Ast.Pattern (head, hrefs, vars), term ->
Ast.Pattern (head, k_xref hrefs, List.map aux_capture_variable vars), k term
| Ast.Wildcard, term -> Ast.Wildcard, k term