3a457e6ad6
Many of our tests in `tests/lean/run/` produce output from `#eval` (or `#check`) statements, that is then ignored. This PR tries to capture all the useful output using `#guard_msgs`. I've only done a cursory check that the output is still sane --- there is a chance that some "unchecked" tests have already accumulated regressions and this just cements them! In the other direction, I did identify two rotten tests: * a minor one in `setStructInstNotation.lean`, where a comment says `Set Nat`, but `#check` actually prints `?_`. Weird? * `CompilerProbe.lean` is generating empty output, apparently indicating that something is broken, but I don't know the signficance of this file. In any case, I'll ask about these elsewhere. (This started by noticing that a recent `grind` test file had an untested `trace_state`, and then got carried away.)
40 lines
1 KiB
Text
40 lines
1 KiB
Text
--
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/-
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This example demonstratea that when we are using `native_decide`,
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we are also trusting the correctness of `implemented_by` annotations,
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foreign functions (i.e., `[extern]` annotations), etc.
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-/
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def g (b : Bool) := false
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/-
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The following `implemented_by` is telling the compiler
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"trust me, `g` does implement `f`"
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which is clearly false in this example.
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-/
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@[implemented_by g]
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def f (b : Bool) := b
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theorem fConst (b : Bool) : f b = false :=
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match b with
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| true =>
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/- The following `native_decide` is going to use `g` to evaluate `f`
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because of the `implemented_by` directive. -/
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have : (f true) = false := by native_decide
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this
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| false => rfl
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theorem trueEqFalse : true = false :=
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have h₁ : f true = true := rfl;
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have h₂ : f true = false := fConst true;
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Eq.trans h₁.symm h₂
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/-
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We managed to prove `False` using the unsound annotation `implemented_by` above.
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-/
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theorem unsound : False :=
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Bool.noConfusion trueEqFalse
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/-- info: 'unsound' depends on axioms: [Lean.ofReduceBool] -/
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#guard_msgs in
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#print axioms unsound
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