4d697874b7
This PR refactors the way simp arguments are elaborated: Instead of changing the `SimpTheorems` structure as we go, this elaborates each argument to a more declarative description of what it does, and then apply those. This enables more interesting checks of simp arguments that need to happen in the context of the eventually constructed simp context (the checks in #8688), or after simp has run (unused argument linter #8901). The new data structure describing an elaborated simp argument isn’t the most elegant, but follows from the code. While I am at it, move handling of `[*]` into `elabSimpArgs`. Downstream adaption branches exist (but may not be fully up to date because of the permission changes). While I am at it, I cleaned up `SimpTheorems.lean` file a bit (sorting declarations, mild renaming) and added documentation.
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 after 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_3 : 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 the 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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