41a2e9af19
This PR makes functions defined by well-founded recursion use an `opaque` well-founded proof by default. This reliably prevents kernel reduction of such definitions and proofs, which tends to be prohibitively slow (fixes #2171), and which regularly causes hard-to-debug kernel type-checking failures. This changes renders `unseal` ineffective for such definitions. To avoid the opaque proof, annotate the function definition with `@[semireducible]`.
33 lines
1 KiB
Text
33 lines
1 KiB
Text
def ack : Nat → Nat → Nat
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| 0, y => y+1
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| x+1, 0 => ack x 1
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| x+1, y+1 => ack x (ack (x+1) y)
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termination_by a b => (a, b)
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/--
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info: [diag] Diagnostics
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[kernel] unfolded declarations (max: 147, num: 3):
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[kernel] OfNat.ofNat ↦ 147
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[kernel] Add.add ↦ 61
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[kernel] HAdd.hAdd ↦ 61
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use `set_option diagnostics.threshold <num>` to control threshold for reporting counters
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---
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info: [simp] Diagnostics
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[simp] used theorems (max: 59, num: 1):
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[simp] ack.eq_3 ↦ 59
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[simp] tried theorems (max: 59, num: 1):
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[simp] ack.eq_3 ↦ 59, succeeded: 59
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use `set_option diagnostics.threshold <num>` to control threshold for reporting counters
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---
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info: [diag] Diagnostics
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[kernel] unfolded declarations (max: 147, num: 3):
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[kernel] OfNat.ofNat ↦ 147
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[kernel] Add.add ↦ 61
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[kernel] HAdd.hAdd ↦ 61
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use `set_option diagnostics.threshold <num>` to control threshold for reporting counters
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-/
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#guard_msgs in
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set_option diagnostics.threshold 50 in
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set_option diagnostics true in
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theorem ex : ack 3 2 = 29 :=
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by simp [ack]
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