lean4-htt/tests/lean/run/try_trace1.lean
Leonardo de Moura b01ca8ee23
feat: use expose_names in try? (#6967)
This PR ensures `try?` can suggest tactics that need to reference
inaccessible local names.
Example: 
```lean
/--
info: Try these:
• · expose_names; induction as, bs_1 using app.induct <;> grind [= app]
• · expose_names; induction as, bs_1 using app.induct <;> grind only [app]
-/
#guard_msgs (info) in
example : app (app as bs) cs = app as (app bs cs) := by
  have bs := 20 -- shadows `bs` in the target
  try?
```
2025-02-06 05:44:25 +00:00

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set_option grind.warning false
/--
info: Try these:
• simp
• simp only [ne_eq, reduceCtorEq, not_false_eq_true]
• grind
• grind only
-/
#guard_msgs (info) in
example : [1, 2] ≠ [] := by
try?
/--
info: Try these:
• simp +arith
• simp +arith only [ge_iff_le]
• grind
• grind only
-/
#guard_msgs (info) in
example : 4 + x + y ≥ 1 + x := by
try?
/--
info: Try these:
• grind
• grind only
-/
#guard_msgs (info) in
example (f : Nat → Nat) : f a = b → a = c → f c = b := by
try?
def f : Nat → Nat
| 0 => 1
| _ => 2
/--
info: Try these:
• grind [= f]
• grind only [f]
-/
#guard_msgs (info) in
example : f (f 0) > 0 := by
try?
/--
info: Try these:
• grind [= f.eq_def]
• grind only [= f.eq_def]
-/
#guard_msgs (info) in
example : f x > 0 := by
try?
def app : List α → List α → List α
| [], bs => bs
| a::as, bs => a :: app as bs
/--
info: Try these:
• rfl
• grind [= app]
• grind only [app]
-/
#guard_msgs (info) in
example : app [a, b] [c] = [a, b, c] := by
try?
/--
info: Try these:
• (induction as, bs using app.induct) <;> grind [= app]
• (induction as, bs using app.induct) <;> grind only [app]
-/
#guard_msgs (info) in
example : app (app as bs) cs = app as (app bs cs) := by
try?
/--
info: Try these:
• · expose_names; induction as, bs_1 using app.induct <;> grind [= app]
• · expose_names; induction as, bs_1 using app.induct <;> grind only [app]
-/
#guard_msgs (info) in
example : app (app as bs) cs = app as (app bs cs) := by
have bs := 20 -- shadow variable in the goal
try?
/--
info: Try these:
• · expose_names; induction as, bs using app.induct <;> grind [= app]
• · expose_names; induction as, bs using app.induct <;> grind only [app]
-/
#guard_msgs (info) in
example : app (app as bs) cs = app as (app bs cs) := by
revert as bs cs
intro _ _ _
-- `as`, `bs`, and `cs` now have inaccessible names.
try?