0520de7374
This PR fixes a bug where `reduceRecMatcher?` and `reduceProj?` bypassed the `@[cbv_opaque]` attribute. These kernel-level reduction functions use `whnf` internally, which does not know about `@[cbv_opaque]`. This meant `@[cbv_opaque]` values were unfolded when they appeared as match discriminants, recursor major premises, or projection targets. The fix introduces `withCbvOpaqueGuard`, which wraps these calls with `withCanUnfoldPred` to prevent `whnf` from unfolding `@[cbv_opaque]` definitions. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
95 lines
2 KiB
Text
95 lines
2 KiB
Text
set_option cbv.warning false
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/-! Test that `@[cbv_opaque]` is respected by `reduceRecMatcher` and `reduceProj`. -/
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/-! `@[cbv_opaque]` constants are not unfolded. -/
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@[cbv_opaque] def secret : Nat := 42
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/--
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error: unsolved goals
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⊢ secret = 42
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-/
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#guard_msgs in
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example : secret = 42 := by conv => lhs; cbv
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/-! Equation theorems fire but `@[cbv_opaque]` arguments stay intact. -/
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def addOne (n : Nat) : Nat := n + 1
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/--
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error: unsolved goals
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⊢ secret.succ = 43
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-/
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#guard_msgs in
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example : addOne secret = 43 := by conv => lhs; cbv
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/-! Pattern matching on a `@[cbv_opaque]` discriminant gets stuck. -/
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def isZero (n : Nat) : Bool :=
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match n with
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| 0 => true
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| _ + 1 => false
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/--
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error: unsolved goals
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⊢ (match secret with
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| 0 => true
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| n.succ => false) =
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false
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-/
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#guard_msgs in
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example : isZero secret = false := by conv => lhs; cbv
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/-! Recursive functions with `@[cbv_opaque]` arguments get stuck at the match. -/
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def myLength : List Nat → Nat
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| [] => 0
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| _ :: xs => 1 + myLength xs
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@[cbv_opaque] def secretList : List Nat := [1, 2, 3]
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/--
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error: unsolved goals
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⊢ (match secretList with
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| [] => 0
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| head :: xs => 1 + myLength xs) =
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3
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-/
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#guard_msgs in
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example : myLength secretList = 3 := by conv => lhs; cbv
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/-! Projections on `@[cbv_opaque]` structures are not reduced. -/
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@[cbv_opaque] def secretPair : Nat × Nat := (10, 20)
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/--
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error: unsolved goals
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⊢ secretPair.1 = 10
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-/
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#guard_msgs in
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example : secretPair.1 = 10 := by conv => lhs; cbv
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/--
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error: unsolved goals
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⊢ secretPair.2 = 20
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-/
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#guard_msgs in
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example : secretPair.2 = 20 := by conv => lhs; cbv
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/-! Non `@[cbv_opaque]` values still reduce normally. -/
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def normalVal : Nat := 42
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example : normalVal + 1 = 43 := by cbv
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example : isZero normalVal = false := by cbv
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def normalPair : Nat × Nat := (10, 20)
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example : normalPair.1 = 10 := by cbv
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example : normalPair.2 = 20 := by cbv
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/-! The kernel's `isDefEq` in `cbvGoalCore` still closes `@[cbv_opaque]` goals. -/
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example : secret = 42 := by cbv
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example : secretPair.1 = 10 := by cbv
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