59a09fb4e7
This assigns priorities to the equational lemmas so that more specific ones are tried first before a possible catch-all with possible side-conditions. We assign very low priorities to match the simplifiers behavior when unfolding a definition, which happens in `simpLoop`’ `visitPreContinue` after applying rewrite rules. Definitions with more than 100 equational theorems will use priority 1 for all but the last (a heuristic, not perfect). fixes #4173, to some extent.
41 lines
1.6 KiB
Text
41 lines
1.6 KiB
Text
import Lean
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/-!
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Tests that simp applies the equational lemmas in order. In particular,
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a catch-all at the end is tried afte the others
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-/
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def foo : Bool → Nat → Nat
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| _, 0 => 0
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| .true, n+1 => foo .true n
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| _, n+1 => foo .false n
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termination_by _ n => n
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/-- info: foo.eq_1 : ∀ (x : Bool), foo x 0 = 0 -/
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#guard_msgs in
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#check foo.eq_1
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/-- info: foo.eq_2 (n : Nat) : foo true n.succ = foo true n -/
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#guard_msgs in
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#check foo.eq_2
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/-- info: foo.eq_3 : ∀ (x : Bool) (n : Nat), (x = true → False) → foo x n.succ = foo false n -/
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#guard_msgs in
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#check foo.eq_3
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-- In order to reliably check if simp is not attempting to rewrite with a certain lemma
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-- we can look at te diagnostics. But simply dumping all diangostics is too noisy for a test,
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-- so here we try to get our hands at the `Simp.Stats` and look there.
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open Lean Meta Elab Tactic in
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elab "simp_foo_with_check" : tactic =>
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withOptions (fun o => diagnostics.set o true) do withMainContext do
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let stx ← `(tactic|simp [foo])
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let { ctx, simprocs, dischargeWrapper } ← mkSimpContext stx (eraseLocal := false)
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let stats ← dischargeWrapper.with fun discharge? => do
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simpLocation ctx simprocs discharge? (expandOptLocation stx.raw[5])
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unless stats.diag.triedThmCounter.toList.any (fun (o, _n) => o.key = ``foo.eq_2) do
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throwError "Simp did not try to use foo.eq_2, is this test still working?"
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for (origin, n) in stats.diag.triedThmCounter.toList do
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if origin.key = ``foo.eq_3 then
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throwError m!"Bad: Simp used foo.eq_3 {n} times"
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example : foo true 1 = 0 := by
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simp_foo_with_check -- essentially simp [foo]
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