lean4-htt/tests/lean/run/909.lean
Kim Morrison 3a457e6ad6
chore: use #guard_msgs in run tests (#4175)
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.)
2024-05-16 00:38:31 +00:00

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structure Date where
val : Nat
deriving Repr
instance : LE Date := ⟨InvImage (Nat.le) Date.val⟩
instance bad (a b : Date) : Decidable (a <= b) :=
if h0 : (a.val <= b.val) then isTrue h0 else isFalse (fun hf => False.elim (h0 hf))
instance : Min Date := minOfLe
/-
This implementation also fails:
instance (a b : Date) : Decidable (a <= b) :=
inferInstanceAs (Decidable (a.val <= b.val))
-/
/-
This implementation evaluates successfully:
instance (a b : Date) : Decidable (a <= b) :=
dite (a.val <= b.val) isTrue (fun nle => isFalse (fun hf => False.elim (nle hf)))
-/
instance : ToString Date where
toString d := s!"D{d.val}"
structure DateRange where
start_ : Date
finish_ : Date
h : start_ <= finish_
def r1 := (DateRange.mk (Date.mk 0) (Date.mk 10) (by decide))
-- If you change the start_ value here to `0`, it works.
def r2 := (DateRange.mk (Date.mk 1) (Date.mk 10) (by decide))
/-- info: { val := 0 } -/
#guard_msgs in
#eval min r1.start_ r2.start_