"bad" simp lemmas can lead to `acyclic` tactic failure with `simp` recursion limit
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Description
Prerequisites
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Description
I assume acyclic should now use omega instead of simp_arith
Context
Steps to Reproduce
import Mathlib.Algebra.Order.Monoid.Lemmas
import Mathlib.Data.Nat.Basic
@[simp] theorem succ_le_iff_lt: n + 1 ≤ k ↔ n < k := sorry
inductive Foo
| mk (x y: Foo)
set_option trace.Meta.Tactic.acyclic true in
example {x y: Foo} (h: x = Foo.mk y x): False := nomatch h
Expected behavior: acyclic can handle such a goal
Actual behavior: acyclic tactic produces an error message:
[Meta.Tactic.acyclic] failed with
tactic 'simp' failed, nested error:
maximum recursion depth has been reached (use `set_option maxRecDepth <num>` to increase limit)
Versions
4.7.0-rc2
Additional Information
Impact
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Research direction
Reproduce the example using the listed Mathlib imports and set_option trace.Meta.Tactic.acyclic true. Start by tracing where acyclic invokes simp or simp_arith, then investigate the reported assumption that it should use omega; done means the example succeeds without increasing maxRecDepth and the recursion error no longer occurs.
Written by the indexing model from the issue text.
Assessment
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 50/100