$ git grep findShardKeyPrefixedIndex -- ':!*test*'
src/mongo/db/commands/dbcommands.cpp:361:                const auto shardKeyIdx = findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/analyze_shard_key_cmd_util.cpp:600:    const auto index = findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/auto_split_vector.cpp:161:        const auto shardKeyIdx = findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/check_sharding_index_command.cpp:105:        const auto shardKeyIdx = findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/metadata_consistency_util.cpp:103:        if (!findShardKeyPrefixedIndex(opCtx, localColl, shardKey, false /*requireSingleKey*/)) {
src/mongo/db/s/migration_chunk_cloner_source.cpp:1065:    const auto shardKeyIdx = findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/range_deletion_util.cpp:89:    const auto shardKeyIdx = findShardKeyPrefixedIndex(
src/mongo/db/s/shard_key_index_util.cpp:45:boost::optional<ShardKeyIndex> _findShardKeyPrefixedIndex(
src/mongo/db/s/shard_key_index_util.cpp:197:    return !_findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/shard_key_index_util.cpp:206:boost::optional<ShardKeyIndex> findShardKeyPrefixedIndex(OperationContext* opCtx,
src/mongo/db/s/shard_key_index_util.cpp:211:    return _findShardKeyPrefixedIndex(opCtx,
src/mongo/db/s/shard_key_index_util.h:93:boost::optional<ShardKeyIndex> findShardKeyPrefixedIndex(OperationContext* opCtx,
src/mongo/db/s/shard_key_util.cpp:416:            findShardKeyPrefixedIndex(_opCtx,
src/mongo/db/s/split_chunk.cpp:214:        const auto shardKeyIdx = findShardKeyPrefixedIndex(
src/mongo/db/s/split_vector.cpp:87:        const auto shardKeyIdx = findShardKeyPrefixedIndex(opCtx,