(module print_str_no_auto_newline
  (fn main
    (doc "RED fixture for Gitea #29: `io/print_str` must print exactly the bytes of its argument with NO auto-newline. Today the codegen lowers this op to a C `@puts(ptr)` call, which writes the string PLUS a trailing newline — so two consecutive prints of single-character strings emit \"a\\nb\\n\" instead of the expected \"ab\". This is the de-facto-println behaviour LLM authors (Qwen3-Coder, naming-A/B run 2026-05-21) trip over when they write explicit `\\n` and get doubled newlines. Property protected once the codegen swaps `@puts` for `fputs(s, stdout)`: io/print_str is a byte-faithful print, the author chooses whether to embed a newline.")
    (type (fn-type (params) (ret (own (con Unit))) (effects IO)))
    (params)
    (body (seq (do io/print_str "a") (do io/print_str "b")))))