This PR fixes a benchmark regression introduced in #13475:
`eqnOptionsExt`
was using `.async .asyncEnv` asyncMode, which accumulates state in the
`checked` environment and can block. Switching to `.local` — consistent
with the neighbouring `eqnsExt` and the other declaration caches in
`src/Lean/Meta` — restores performance (the
`build/profile/blocked (unaccounted) wall-clock` bench moves from +33%
back to baseline). `.local` is safe here because
`saveEqnAffectingOptions`
is only called during top-level `def` elaboration and downstream readers
see the imported state; modifications on non-main branches are merged
into the main branch on completion.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>