simp only [Option.some_bind] -> maximum recursion depth has been reached
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Description
Prerequisites
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- Check that your issue is not already filed:
https://github.com/leanprover/lean4/issues - Reduce the issue to a minimal, self-contained, reproducible test case.
Avoid dependencies to Mathlib or Batteries. - Test your test case against the latest nightly release, for example on
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Description
theorem extracted_1 (e : Option (BitVec 32)) :
none =
Option.bind e fun x =>
if x ≥ 32 then none
else
(some ((BitVec.ofInt 32 (-33)).sshiftRight x.toNat)).bind fun y =>
if y = 0#32 then none else some 0#32 := by
simp only [Option.some_bind]
/-
tactic 'simp' failed, nested error:
maximum recursion depth has been reached
use `set_option maxRecDepth <num>` to increase limit
use `set_option diagnostics true` to get diagnostic information
-/
Context
I checked with @hargoniX and this seems to be a bug.
Steps to Reproduce
- Copy into live.lean-lang.org
- Observe the error
Expected behavior: No error recursion error
Actual behavior: Either simp successfully terminating or reporting that it could not find a simp-lemma to apply
Versions
Lean 4.14.0-nightly-2024-11-03
Target: x86_64-unknown-linux-gnu
Further information
On our dataset, this (or a similar) simp error fires 82 times.
Impact
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Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the minimal reproducer in live.lean-lang.org and inspect the behavior of simp only [Option.some_bind] on the shown theorem. Done means the command terminates without a maximum-recursion-depth error, either simplifying the goal or reporting that no applicable simp lemma was found.
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
- Clearly specified
- Newbie friendliness
- 45/100