The macOS leg of the check job runs one race-enabled pass, so the tests that assert only without the race detector (cost guards that skip under -race or drop their CPU bound there, 43 of them on 2026-10-18) run there and assert nothing: their bounds are checked on the ubuntu leg only, never on macOS. The workflow comment said dropping the plain pass dropped no test, which those tests had made untrue.

The macOS leg of the check job runs one race-enabled pass, so the tests that assert only without the race detector (cost guards that skip under -race or drop their CPU bound there, 43 of them on 2026-10-18) run there and assert nothing: their bounds are checked on the ubuntu leg only, never on macOS. The workflow comment said dropping the plain pass dropped no test, which those tests had made untrue.

Grounds

• pursued: the macOS leg grows by about a minute and stays well inside its 60-minute ceiling; a merge-group macOS run above 50 minutes, where the warning fires, would show it wrong