2ce55ba460
This PR fixes #12554 where the `cbv` tactic throws "unexpected kernel projection term during structural definitional equality" when a rewrite theorem's pattern contains a lambda and the expression being matched has a `.proj` (kernel projection) at the corresponding position. The `Sym` pattern matching infrastructure (`isDefEqMain` in `Pattern.lean`) does not handle `.proj` expressions and can throw an exception. Rather than presenting it as an error in `cbv`, we fail quietly and let the `cbv` tactic try other fallback paths. --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
23 lines
667 B
Text
23 lines
667 B
Text
-- Regression test for https://github.com/leanprover/lean4/issues/12554
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def applyFn (f : Nat → Nat) (x : Nat) : Nat := f x
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@[cbv_eval] theorem applyFn_id : applyFn (fun x => x) = fun x => x := by
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funext x; rfl
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opaque fnPair : (Nat → Nat) × Nat
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-- The `.proj` in `fnPair.1` caused pattern matching against the lambda in
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-- `applyFn_id` to throw.
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example : applyFn fnPair.1 42 = fnPair.1 42 := by cbv
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opaque pair : Nat × Nat
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def myId (x : Nat) : Nat := x
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example : myId pair.1 = pair.1 := by cbv
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def isZero : Nat → Bool
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| 0 => true
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| _ + 1 => false
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example : isZero pair.1 = isZero pair.1 := by cbv
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example : applyFn (fun x => x) 42 = 42 := by cbv
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