1fa67d0d47
This PR fixes a case of overeager constant folding on Nat where the compiler would mistakenly assume `0 - x = x` (see also #11042 for the same bug on UInts).
26 lines
772 B
Text
26 lines
772 B
Text
/-!
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This test guards against a constant folding bug
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-/
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def danger : UInt64 := UInt64.ofNat UInt64.size - 1
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theorem danger_eq_large : danger = 18446744073709551615 := by decide +kernel
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/--
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error: Tactic `native_decide` evaluated that the proposition
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danger = 1
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is false
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-/
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#guard_msgs in
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theorem danger_eq_one : danger = 1 := by native_decide
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theorem bad : False := by simpa using danger_eq_large.symm.trans danger_eq_one
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def danger2 (x : Nat) : Nat := 0 - x
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theorem danger2_eq_zero : danger2 1 = 0 := by decide +kernel
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/--
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error: Tactic `native_decide` evaluated that the proposition
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danger2 1 = 1
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is false
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-/
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#guard_msgs in
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theorem danger2_eq_one : danger2 1 = 1 := by native_decide
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theorem bad2 : False := by simpa using danger2_eq_zero.symm.trans danger2_eq_one
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