syntax_data: {"ast_node_type":"other","tokens":[{"end":51,"kind":"keyword","start":0,"text":"|(i,"}]}
source_snippet:             |(i, (arg, v))| match (arg.kind(), v) {
context_before:         std::iter::zip(self.args.iter(), variances.iter()).enumerate().filter_map(
context_after:                 (_, ty::Invariant) => Some((i, arg)),