debug!(?kind, ?obligation, "assemble_unboxed_candidates");
match self.infcx.closure_kind(closure_substs) {
Some(closure_kind) => {
debug!(?closure_kind, "assemble_unboxed_candidates");
if closure_kind.extends(kind) {
debug!(?kind, ?obligation, "assemble_unboxed_candidates");
match self.infcx.closure_kind(closure_substs) {
Some(closure_kind) => {
debug!(?closure_kind, "assemble_unboxed_candidates");
if closure_kind.extends(kind) {