lean4-htt/tests/elab/issue10749.lean
Leonardo de Moura adc45d7c7b
feat: mark exposed match auxiliary declarations as implicit_reducible (#13281)
This PR marks any exposed (non-private) auxiliary match declaration as
`[implicit_reducible]`. This is essential when the outer declaration is
marked as `instance_reducible` — without it, reduction is blocked at the
match auxiliary. We do not inherit the attribute from the parent
declaration because match auxiliary declarations are reused across
definitions, and the reducibility setting of the parent can change
independently. This change prepares for implementing the TODO at
`ExprDefEq.lean:465`, which would otherwise cause too many failures
requiring manual `[implicit_reducible]` annotations on match
declarations whose names are not necessarily derived from the outer
function.

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-04 23:55:47 +00:00

138 lines
4.9 KiB
Text

-- set_option trace.Meta.Match.debug true
-- set_option trace.Meta.Match.match true
set_option match.ignoreUnusedAlts true in
def test (a : List Nat) : Nat :=
match a with
| _ => 3
| [] => 4
-- Should have no `casesOn`
/--
info: @[implicit_reducible] def test.match_1.{u_1} : (motive : List Nat → Sort u_1) →
(a : List Nat) → ((x : List Nat) → motive x) → (Unit → motive []) → motive a :=
fun motive a h_1 h_2 => h_1 a
-/
#guard_msgs in #print test.match_1
def test2 (a b : List Nat) : Nat :=
match a, b with
| [], _ => 3
| _, [] => 4
| _ :: _, _ :: _ => 5
-- Should have exactly two `casesOn`
/--
info: @[implicit_reducible] def test2.match_1.{u_1} : (motive : List Nat → List Nat → Sort u_1) →
(a b : List Nat) →
((x : List Nat) → motive [] x) →
((x : List Nat) → motive x []) →
((head : Nat) →
(tail : List Nat) → (head_1 : Nat) → (tail_1 : List Nat) → motive (head :: tail) (head_1 :: tail_1)) →
motive a b :=
fun motive a b h_1 h_2 h_3 =>
List.casesOn a (h_1 b) fun head tail =>
List.casesOn b (h_2 (head :: tail)) fun head_1 tail_1 => h_3 head tail head_1 tail_1
-/
#guard_msgs in #print test2.match_1
def test3 (a : List Nat) (b : Bool) : Nat :=
match a, b with
| _, true => 0
| [], _ => 1
| _, _ => 2
-- Should have exactly two `casesOn`
/--
info: @[implicit_reducible] def test3.match_1.{u_1} : (motive : List Nat → Bool → Sort u_1) →
(a : List Nat) →
(b : Bool) →
((x : List Nat) → motive x true) →
((x : Bool) → motive [] x) → ((x : List Nat) → (x_1 : Bool) → motive x x_1) → motive a b :=
fun motive a b h_1 h_2 h_3 =>
test3._sparseCasesOn_1 b (h_1 a) fun h => test3._sparseCasesOn_2 a (h_2 b) fun h => h_3 a b
-/
#guard_msgs in #print test3.match_1
set_option maxHeartbeats 100 in
example (P : Nat → Prop) (x : Nat) (h : x = 12345) (hP : P 12345) : P x :=
match x, h with | _, rfl => hP
def test4 : Bool → Bool → Bool → Bool → Bool → Bool
| _, _ , _ , _ , true => true
| _, _ , _ , true, _ => true
| _, _ , true, _ , _ => true
| _, true, _ , _ , _ => true
| true, _ , _ , _ , _ => true
| _ , _ , _ , _ , _ => false
/--
info: @[implicit_reducible] def test4.match_1.{u_1} : (motive : Bool → Bool → Bool → Bool → Bool → Sort u_1) →
(x x_1 x_2 x_3 x_4 : Bool) →
((x x_5 x_6 x_7 : Bool) → motive x x_5 x_6 x_7 true) →
((x x_5 x_6 x_7 : Bool) → motive x x_5 x_6 true x_7) →
((x x_5 x_6 x_7 : Bool) → motive x x_5 true x_6 x_7) →
((x x_5 x_6 x_7 : Bool) → motive x true x_5 x_6 x_7) →
((x x_5 x_6 x_7 : Bool) → motive true x x_5 x_6 x_7) →
((x x_5 x_6 x_7 x_8 : Bool) → motive x x_5 x_6 x_7 x_8) → motive x x_1 x_2 x_3 x_4 :=
fun motive x x_1 x_2 x_3 x_4 h_1 h_2 h_3 h_4 h_5 h_6 =>
test3._sparseCasesOn_1 x_4 (h_1 x x_1 x_2 x_3) fun h =>
test3._sparseCasesOn_1 x_3 (h_2 x x_1 x_2 x_4) fun h =>
test3._sparseCasesOn_1 x_2 (h_3 x x_1 x_3 x_4) fun h =>
test3._sparseCasesOn_1 x_1 (h_4 x x_2 x_3 x_4) fun h =>
test3._sparseCasesOn_1 x (h_5 x_1 x_2 x_3 x_4) fun h => h_6 x x_1 x_2 x_3 x_4
-/
#guard_msgs in
#print test4.match_1
def test4' : Bool → Bool → Bool → Bool → Bool → Bool
| _, _ , _ , _ , true => true
| _, _ , _ , true, _ => true
| _, _ , true, _ , _ => true
| _, true, _ , _ , _ => true
| true, _ , _ , _ , _ => true
| false, false, false, false, false => false
/--
info: @[implicit_reducible] def test4'.match_1.{u_1} : (motive : Bool → Bool → Bool → Bool → Bool → Sort u_1) →
(x x_1 x_2 x_3 x_4 : Bool) →
((x x_5 x_6 x_7 : Bool) → motive x x_5 x_6 x_7 true) →
((x x_5 x_6 x_7 : Bool) → motive x x_5 x_6 true x_7) →
((x x_5 x_6 x_7 : Bool) → motive x x_5 true x_6 x_7) →
((x x_5 x_6 x_7 : Bool) → motive x true x_5 x_6 x_7) →
((x x_5 x_6 x_7 : Bool) → motive true x x_5 x_6 x_7) →
(Unit → motive false false false false false) → motive x x_1 x_2 x_3 x_4 :=
fun motive x x_1 x_2 x_3 x_4 h_1 h_2 h_3 h_4 h_5 h_6 =>
Bool.casesOn x_4
(Bool.casesOn x_3
(Bool.casesOn x_2
(Bool.casesOn x_1 (Bool.casesOn x (h_6 ()) (h_5 false false false false)) (h_4 x false false false))
(h_3 x x_1 false false))
(h_2 x x_1 x_2 false))
(h_1 x x_1 x_2 x_3)
-/
#guard_msgs in
#print test4'.match_1
-- Just testing the backwards compatibility option
set_option match.ignoreUnusedAlts true in
set_option backward.match.rowMajor false in
def testOld (a : List Nat) : Nat :=
match a with
| _ => 3
| [] => 4
-- Has unnecessary `casesOn`
/--
info: @[implicit_reducible] def testOld.match_1.{u_1} : (motive : List Nat → Sort u_1) →
(a : List Nat) → ((x : List Nat) → motive x) → (Unit → motive []) → motive a :=
fun motive a h_1 h_2 => test3._sparseCasesOn_2 a (h_1 []) fun h => h_1 a
-/
#guard_msgs in
#print testOld.match_1