Function run_checks 

pub async fn run_checks(
    runner: impl Runner,
    submission: &str,
    checks: &[String],
) -> Vec<CheckOutcome>

Run each check against submission through runner, returning one CheckOutcome per check, in order.

Effectful (§2.2). The submission is first run on its own: if it cannot execute — a syntax error, or a launch failure — every check is NotRun, because no check could have a verdict (§3.3). This standalone gate is load-bearing: concatenating the submission with a check and reading the combined exit code cannot tell a broken submission from a violated check (and some interpreters, R among them, would even splice an unterminated submission into the check). Once the submission runs cleanly, each check is the submission followed by the check code-string; the check passes when that program exits cleanly and fails otherwise. Outcomes are element-wise — never folded into a single aggregate verdict.

With no checks there is nothing to classify, so the submission is not run at all — an LLM-only lesson (the common case) never pays for a subprocess here.