{"ast_node_type":"other","tokens":[{"end":156,"kind":"keyword","start":0,"text":"UpvarMigrationInfo::CapturingNothing"}]}
                                    UpvarMigrationInfo::CapturingNothing { use_span } => span_bug!(*use_span, "missing trait from not capturing something"),
                                    // Cannot happen: if we don't capture a variable, we impl strictly more traits
                                }