Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
916004bd3c
This PR moves `hasAssignableMVar`, `hasAssignableLevelMVar`, and `isLevelMVarAssignable` from `MetavarContext.lean` to a new `Lean.Meta.HasAssignableMVar` module, changing them from generic `[Monad m] [MonadMCtx m]` functions to `MetaM` functions. This enables adding `checkSystem` calls in the recursive traversal, which ensures cancellation and heartbeat checks happen during what can be a very expensive computation. All callers of these functions were already in `MetaM`, so this change is safe. The motivating case is the `4595_slowdown.lean` test, where `hasAssignableMVar` (with `PersistentHashMap.find?` lookups on `mctx.lDepth`) was the dominant CPU cost during elaboration of category theory definitions. Without `checkSystem` calls, cancellation requests could be delayed by over 2 seconds. The test file `4595_slowdown.lean` gets a slightly increased `maxHeartbeats` limit because `checkSystem` now detects heartbeat exhaustion mid-traversal rather than after the function returns. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> |
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