MessagesIterator.next called notmuch_threads_status on a notmuch_messages_t, which is a type error, so any caller failed to compile. FilenamesIterator.next used the notmuch_threads_* functions throughout and returned a struct literal where a string was expected. All three iterators also had their validity check inverted: a non-zero notmuch_*_valid means an item is available, so testing "!= 0" ended iteration immediately and every search yielded nothing. The unit tests missed all of this because refAllDecls does not analyze function bodies, and refAllDeclsRecursive no longer exists in Zig 0.16. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QUkL1WZxTCYKWEo6acapsE