1c1c534a03
This PR adds `solve_by_elim` as a fallback in the `try?` tactic's simple
tactics. When `rfl` and `assumption` both fail but `solve_by_elim`
succeeds (e.g., for goals requiring hypothesis chaining or
backtracking), `try?` will now suggest `solve_by_elim`.
The structure is `first | (attempt_all | rfl | assumption) |
solve_by_elim`, so `solve_by_elim` only runs when the faster tactics
fail.
This is a prerequisite for removing the "first pass" `solve_by_elim`
from `apply?`. Currently `apply?` calls `solve_by_elim` twice: once
before library search, and once after each lemma application. The first
pass can be removed once `try?` includes `solve_by_elim`.
🤖 Prepared with Claude Code
---------
Co-authored-by: Claude <noreply@anthropic.com>
78 lines
2.3 KiB
Text
78 lines
2.3 KiB
Text
/-
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Tests for heartbeat management in `try?`
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This file tests that:
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1. Each tactic execution gets a fresh heartbeat budget with the original limit
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2. Tactics that exceed heartbeat limits are filtered out from try? suggestions
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3. `attempt_all` continues past heartbeat failures to find working tactics
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-/
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module
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public import Lean
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public meta import Lean.Elab.Tactic.Try
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open Lean Meta Elab Tactic Try
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-- Define an opaque proposition that built-in tactics (including solve_by_elim) won't solve
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opaque CustomGoal : Prop
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axiom customGoalHolds : CustomGoal
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-- Create a tactic that consumes heartbeats through meta operations
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elab "expensive_meta_tactic" : tactic => do
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for _ in [:10000] do
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let mvar ← mkFreshExprMVar (some (mkConst ``Nat))
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let _ ← instantiateMVars mvar
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evalTactic (← `(tactic| exact customGoalHolds))
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-- Verify that expensive_meta_tactic actually consumes heartbeats:
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-- It times out at 100 heartbeats
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set_option maxHeartbeats 100 in
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/--
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error: (deterministic) timeout at `«tactic execution»`, maximum number of heartbeats (100) has been reached
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Note: Use `set_option maxHeartbeats <num>` to set the limit.
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Hint: Additional diagnostic information may be available using the `set_option diagnostics true` command.
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-/
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#guard_msgs in
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example : CustomGoal := by
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expensive_meta_tactic
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-- It succeeds with 500 heartbeats (establishes threshold)
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set_option maxHeartbeats 500 in
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#guard_msgs in
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example : CustomGoal := by
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expensive_meta_tactic
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-- Now register it as a try? suggestion along with a cheap alternative
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@[local try_suggestion 900]
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meta def expensiveSolver (_ : MVarId) (_ : Try.Info) : MetaM (Array (TSyntax `tactic)) := do
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return #[← `(tactic| expensive_meta_tactic)]
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@[local try_suggestion 700]
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meta def cheapSolver (_ : MVarId) (_ : Try.Info) : MetaM (Array (TSyntax `tactic)) := do
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return #[← `(tactic| exact customGoalHolds)]
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-- With 100 heartbeats
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-- expensive_meta_tactic should be filtered out from try? suggestions
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-- Only `customGoalHolds`` should appear
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set_option maxHeartbeats 100 in
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/--
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info: Try this:
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[apply] exact customGoalHolds✝
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-/
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#guard_msgs in
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example : CustomGoal := by
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try?
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-- With 500 heartbeats, both should appear.
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/--
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info: Try these:
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[apply] expensive_meta_tactic
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[apply] exact customGoalHolds✝
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-/
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#guard_msgs in
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set_option maxHeartbeats 500 in
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example : CustomGoal := by
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try?
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