`#lint` in a scratch file that imports your module checks nothing; use `#lint in <Prefix>`

A check file like import My.Module then #lint reports 'Found 0 errors in 0 declarations ... in the current file' and 'All linting checks passed!'. That is vacuous: bare #lint only lints declarations in the current file, and the scratch file has none. Use #lint in My (or #lint in My.Sub), which lints every declaration whose module has that prefix. Check that the reported declaration count is nonzero. The same pitfall applies to any 'lint clean' claim made via a separate check file.