62f14514da
This PR updates various error messages produced by or associated with built-in tactics and adapts their formatting to current conventions.
50 lines
1.7 KiB
Text
50 lines
1.7 KiB
Text
@[semireducible]
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def sorted_from_var [x: LE α] [DecidableRel x.le] (a: Array α) (i: Nat): Bool :=
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if h: i + 1 < a.size then
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have : i < a.size := Nat.lt_of_succ_lt h
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a[i] ≤ a[i+1] && sorted_from_var a (i + 1)
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else
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true
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termination_by a.size - i
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attribute [irreducible] sorted_from_var
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def check_sorted [x: LE α] [DecidableRel x.le] (a: Array α): Bool :=
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sorted_from_var a 0
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/--
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error: Tactic `rfl` failed: The left-hand side
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check_sorted #[0, 3, 3, 5, 8, 10, 10, 10]
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is not definitionally equal to the right-hand side
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true
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⊢ check_sorted #[0, 3, 3, 5, 8, 10, 10, 10] = true
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-/
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#guard_msgs in
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example: check_sorted #[0, 3, 3, 5, 8, 10, 10, 10] = true := by
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rfl -- fails because `rfl` uses `.default` transparency, and `sorted_from_var` is marked as irreducible
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/--
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error: Tactic `decide` failed for proposition
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check_sorted #[0, 3, 3, 5, 8, 10, 10, 10] = true
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because its `Decidable` instance
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instDecidableEqBool (check_sorted #[0, 3, 3, 5, 8, 10, 10, 10]) true
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did not reduce to `isTrue` or `isFalse`.
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After unfolding the instances `instDecidableEqBool` and `Bool.decEq`, reduction got stuck at the `Decidable` instance
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match check_sorted #[0, 3, 3, 5, 8, 10, 10, 10], true with
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| false, false => isTrue ⋯
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| false, true => isFalse ⋯
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| true, false => isFalse ⋯
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| true, true => isTrue ⋯
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-/
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#guard_msgs in
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example: check_sorted #[0, 3, 3, 5, 8, 10, 10, 10] := by
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decide -- fails because `decide` uses `.default` transparency, and `sorted_from_var` is marked as irreducible
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unseal sorted_from_var in
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example: check_sorted #[0, 3, 3, 5, 8, 10, 10, 10] := by
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decide -- works
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example: check_sorted #[0, 3, 3, 5, 8, 10, 10, 10] := by
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with_unfolding_all decide -- should work
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