ac9a1cb415
This PR introduces stricter inference for the `@[defeq]` attribute and a companion `@[backward_defeq]` attribute that preserves the pre-PR behavior as an opt-in. ### What changed * `@[defeq]` is now inferred only when the equation holds at `.instances` transparency (the transparency `dsimp` operates at). * `@[backward_defeq]` is the old set: every theorem whose `rfl` proof the legacy inference would have accepted is tagged `@[backward_defeq]`, so `defeq ⊆ backward_defeq` holds by construction. * The option `backward.defeqAttrib.useBackward` (default `false`) makes `dsimp` also use `@[backward_defeq]` theorems, restoring the pre-PR behavior for a specific proof or file. * The option is eqn-affecting: its value at the point of a function's definition is recorded so that the equation lemmas later generated for that function use the same value, regardless of the ambient option at the use site. ### Mathlib adaption A companion adaption branch (`lean-pr-testing-backward-defeq-attrib` on mathlib4) builds cleanly against this PR and passes `lake test` without warnings. Most adaption changes are scoped `set_option backward.defeqAttrib.useBackward true in` additions on the failing declarations; a small number of files needed proof-level edits where the stored form of a `dsimp%`/`@[reassoc]`/`@[elementwise]` /`@[simps]`/`@[to_app]`-generated lemma had drifted under the stricter regime. --------- Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
84 lines
2.5 KiB
Text
84 lines
2.5 KiB
Text
import Module.Basic
|
|
import Lean
|
|
|
|
/-- info: @[backward_defeq] theorem f.eq_def : f = 1 -/
|
|
#guard_msgs in #print sig f.eq_def
|
|
|
|
/-- info: @[backward_defeq] theorem f.eq_unfold : f = 1 -/
|
|
#guard_msgs in #print sig f.eq_unfold
|
|
|
|
/-- info: @[backward_defeq] theorem f_struct.eq_1 : f_struct 0 = 0 -/
|
|
#guard_msgs in #print sig f_struct.eq_1
|
|
/--
|
|
info: theorem f_struct.eq_def : ∀ (x : Nat),
|
|
f_struct x =
|
|
match x with
|
|
| 0 => 0
|
|
| n.succ => f_struct n
|
|
-/
|
|
#guard_msgs in #print sig f_struct.eq_def
|
|
|
|
/--
|
|
info: theorem f_struct.eq_unfold : f_struct = fun x =>
|
|
match x with
|
|
| 0 => 0
|
|
| n.succ => f_struct n
|
|
-/
|
|
#guard_msgs in #print sig f_struct.eq_unfold
|
|
|
|
/-- info: theorem f_wfrec.eq_1 : ∀ (x : Nat), f_wfrec 0 x = x -/
|
|
#guard_msgs(pass trace, all) in #print sig f_wfrec.eq_1
|
|
|
|
/--
|
|
info: theorem f_wfrec.eq_def : ∀ (x x_1 : Nat),
|
|
f_wfrec x x_1 =
|
|
match x, x_1 with
|
|
| 0, acc => acc
|
|
| n.succ, acc => f_wfrec n (acc + 1)
|
|
-/
|
|
#guard_msgs(pass trace, all) in #print sig f_wfrec.eq_def
|
|
|
|
/--
|
|
info: theorem f_wfrec.eq_unfold : f_wfrec = fun x x_1 =>
|
|
match x, x_1 with
|
|
| 0, acc => acc
|
|
| n.succ, acc => f_wfrec n (acc + 1)
|
|
-/
|
|
#guard_msgs(pass trace, all) in #print sig f_wfrec.eq_unfold
|
|
|
|
/--
|
|
info: theorem f_wfrec.induct_unfolding : ∀ (motive : Nat → Nat → Nat → Prop),
|
|
(∀ (acc : Nat), motive 0 acc acc) →
|
|
(∀ (n acc : Nat), motive n (acc + 1) (f_wfrec n (acc + 1)) → motive n.succ acc (f_wfrec n (acc + 1))) →
|
|
∀ (a a_1 : Nat), motive a a_1 (f_wfrec a a_1)
|
|
-/
|
|
#guard_msgs(pass trace, all) in #print sig f_wfrec.induct_unfolding
|
|
|
|
/-- info: theorem f_exp_wfrec.eq_1 : ∀ (x : Nat), f_exp_wfrec 0 x = x -/
|
|
#guard_msgs(pass trace, all) in
|
|
#print sig f_exp_wfrec.eq_1
|
|
|
|
/--
|
|
info: theorem f_exp_wfrec.eq_def : ∀ (x x_1 : Nat),
|
|
f_exp_wfrec x x_1 =
|
|
match x, x_1 with
|
|
| 0, acc => acc
|
|
| n.succ, acc => f_exp_wfrec n (acc + 1)
|
|
-/
|
|
#guard_msgs in #print sig f_exp_wfrec.eq_def
|
|
|
|
/--
|
|
info: theorem f_exp_wfrec.eq_unfold : f_exp_wfrec = fun x x_1 =>
|
|
match x, x_1 with
|
|
| 0, acc => acc
|
|
| n.succ, acc => f_exp_wfrec n (acc + 1)
|
|
-/
|
|
#guard_msgs(pass trace, all) in #print sig f_exp_wfrec.eq_unfold
|
|
|
|
/--
|
|
info: theorem f_exp_wfrec.induct_unfolding : ∀ (motive : Nat → Nat → Nat → Prop),
|
|
(∀ (acc : Nat), motive 0 acc acc) →
|
|
(∀ (n acc : Nat), motive n (acc + 1) (f_exp_wfrec n (acc + 1)) → motive n.succ acc (f_exp_wfrec n (acc + 1))) →
|
|
∀ (a a_1 : Nat), motive a a_1 (f_exp_wfrec a a_1)
|
|
-/
|
|
#guard_msgs(pass trace, all) in #print sig f_exp_wfrec.induct_unfolding
|