Clang analyzer warning for modulo and size_t

/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:38:62: warning: The result of the '' expression is undefined [clang-analyzer-core.UndefinedBinaryOperatorResult]
    return ht->num_buckets > 0 ? (ht->hash_fn(key, ht->seed) % ht->num_buckets)
                                                             ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:264:9: note: Assuming 'key' is non-null
    if (!key || !ht) {
        ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:264:9: note: Left side of '||' is false
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:264:17: note: Assuming 'ht' is non-null
    if (!key || !ht) {
                ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:264:5: note: Taking false branch
    if (!key || !ht) {
    ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:269:12: note: Calling 'htable_add_to_bucket'
    return htable_add_to_bucket(ht, key, value, false);
           ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:45:10: note: 'ht' is non-null
    if (!ht || !key) {
         ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:45:9: note: Left side of '||' is false
    if (!ht || !key) {
        ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:45:17: note: 'key' is non-null
    if (!ht || !key) {
                ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:45:5: note: Taking false branch
    if (!ht || !key) {
    ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:49:18: note: Calling 'htable_bucket_idx'
    size_t idx = htable_bucket_idx(ht, key);
                 ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:34:10: note: 'ht' is non-null
    if (!ht || !key) {
         ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:34:9: note: Left side of '||' is false
    if (!ht || !key) {
        ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:34:17: note: 'key' is non-null
    if (!ht || !key) {
                ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:34:5: note: Taking false branch
    if (!ht || !key) {
    ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:38:16: note: Field 'num_buckets' is > 0
    return ht->num_buckets > 0 ? (ht->hash_fn(key, ht->seed) % ht->num_buckets)
               ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:38:12: note: '?' condition is true
    return ht->num_buckets > 0 ? (ht->hash_fn(key, ht->seed) % ht->num_buckets)
           ^
/home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c:38:62: note: The result of the '' expression is undefined
    return ht->num_buckets > 0 ? (ht->hash_fn(key, ht->seed) % ht->num_buckets)
                                                             ^
Checking /home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c ...
Checking /home/someusername/bwsync/workspace/uni/master/src/data-struct/htable.c: THREADS=4/2...