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]`.
12 lines
304 B
Text
12 lines
304 B
Text
def g (n : Nat) : Nat :=
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if h : n = 0 then
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1
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else
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4 + g (n - 1)
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termination_by n
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decreasing_by simp_wf; omega
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example : g 10000 = id g (id 10000) := rfl
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example : id g 10000 = id g (id 10000) := rfl
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example : g 10000 + 0 = g (id 10000) + 0 := rfl
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example : g 10000 = g (id 10000) := rfl
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