chore: add note

This PR fixes theory propagation issue in `grind order`.

src/Lean/Meta/Tactic/Grind/Order/Assert.lean

@@ -111,13 +111,23 @@ def propagatePending : OrderM Unit := do
         let h ← mkEqProofOfLeOfLe ue ve huv hvu
         pushEq ue ve h
 
+/--
+Returns `true` if `e` is already `True` in the `grind` core.
+Recall that `e` may be an auxiliary term created for a term `e'` (see `cnstrsMapInv`).
+-/
+private def isAlreadyTrue (e : Expr) : OrderM Bool := do
+  if let some (e', _) := (← get').cnstrsMapInv.find? { expr := e } then
+    alreadyInternalized e' <&&> isEqTrue e'
+  else
+    alreadyInternalized e <&&> isEqTrue e
+
 /--
 Given `e` represented by constraint `c` (from `u` to `v`).
 Checks whether `e = True` can be propagated using the path `u --(k)--> v`.
 If it can, adds a new entry to propagation list.
 -/
 def checkEqTrue (u v : NodeId) (k : Weight) (c : Cnstr NodeId) (e : Expr) : OrderM Bool := do
-  if (← alreadyInternalized e <&&> isEqTrue e) then return true
+  if (← isAlreadyTrue e) then return true
   let k' := c.getWeight
   trace[grind.debug.order.check_eq_true] "{← getExpr u}, {← getExpr v}, {k}, {k'}, {← c.pp}"
   if k ≤ k' then
@@ -126,13 +136,23 @@ def checkEqTrue (u v : NodeId) (k : Weight) (c : Cnstr NodeId) (e : Expr) : Orde
   else
     return false
 
+/--
+Returns `true` if `e` is already `False` in the `grind` core.
+Recall that `e` may be an auxiliary term created for a term `e'` (see `cnstrsMapInv`).
+-/
+private def isAlreadyFalse (e : Expr) : OrderM Bool := do
+  if let some (e', _) := (← get').cnstrsMapInv.find? { expr := e } then
+    alreadyInternalized e' <&&> isEqFalse e'
+  else
+    alreadyInternalized e <&&> isEqFalse e
+
 /--
 Given `e` represented by constraint `c` (from `v` to `u`).
 Checks whether `e = False` can be propagated using the path `u --(k)--> v`.
 If it can, adds a new entry to propagation list.
 -/
 def checkEqFalse (u v : NodeId) (k : Weight) (c : Cnstr NodeId) (e : Expr) : OrderM Bool := do
-  if (← alreadyInternalized e <&&> isEqFalse e) then return true
+  if (← isAlreadyFalse e) then return true
   let k' := c.getWeight
   trace[grind.debug.order.check_eq_false] "{← getExpr u}, {← getExpr v}, {k}, {k'} {← c.pp}"
   if (k + k').isNeg  then
@@ -168,8 +188,8 @@ def checkEq (u v : NodeId) (k : Weight) : OrderM Unit := do
 
 /-- Finds constrains and equalities to be propagated. -/
 def checkToPropagate (u v : NodeId) (k : Weight) : OrderM Unit := do
-  updateCnstrsOf u v fun c e => return !(← checkEqTrue u v k c e)
-  updateCnstrsOf v u fun c e => return !(← checkEqFalse u v k c e)
+  updateCnstrsOf u v fun c e => checkEqTrue u v k c e
+  updateCnstrsOf v u fun c e => checkEqFalse u v k c e
   checkEq u v k
 
 /--

tests/lean/run/grind_indexmap_trace.lean

@@ -239,7 +239,7 @@ example (m : IndexMap α β) (a a' : α) (b : β) :
 /--
 info: Try this:
   [apply] ⏎
-    instantiate only [= getElem_def, insert]
+    instantiate approx [= getElem_def, = mem_indices_of_mem, insert]
     instantiate only [= getElem?_neg, = getElem?_pos]
     cases #f590
     next =>
@@ -249,8 +249,7 @@ info: Try this:
         instantiate only [= Array.getElem_set]
       next =>
         instantiate only
-        instantiate approx [= HashMap.getElem_insert, = Array.size_push, size, = Array.getElem_push,
-          = HashMap.contains_insert, = HashMap.mem_insert, = Array.size_push]
+        instantiate only [= Array.getElem_push, size, = HashMap.getElem_insert, = HashMap.mem_insert]
     next =>
       instantiate only [= getElem_def, = mem_indices_of_mem]
       instantiate only [usr getElem_indices_lt]
@@ -272,7 +271,8 @@ example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
 example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
     (m.insert a b)[a'] = if h' : a' == a then b else m[a'] := by
   grind =>
-    instantiate only [= getElem_def, insert]
+    -- **TODO**: Check approx here
+    instantiate approx [= getElem_def, = mem_indices_of_mem, insert]
     instantiate only [= getElem?_neg, = getElem?_pos]
     cases #f590
     next =>
@@ -282,9 +282,8 @@ example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
         instantiate only [= Array.getElem_set]
       next =>
         instantiate only
-        -- **TODO**: Investigate why we need `approx` here
-        instantiate approx [= HashMap.getElem_insert, = Array.size_push, size, = Array.getElem_push,
-          = HashMap.contains_insert, = HashMap.mem_insert, = Array.size_push]
+        instantiate only [= Array.getElem_push, size, = HashMap.getElem_insert,
+          = HashMap.mem_insert]
     next =>
       instantiate only [= getElem_def, = mem_indices_of_mem]
       instantiate only [usr getElem_indices_lt]

tests/lean/run/grind_order_issue.lean

@@ -0,0 +1,128 @@
+import Std.Data.HashMap
+set_option warn.sorry false
+macro_rules | `(tactic| get_elem_tactic_extensible) => `(tactic| grind)
+
+open Std
+
+structure IndexMap (α : Type u) (β : Type v) [BEq α] [Hashable α] where
+  private indices : HashMap α Nat
+  private keys : Array α
+  private values : Array β
+  private size_keys' : keys.size = values.size := by grind
+  private WF : ∀ (i : Nat) (a : α), keys[i]? = some a ↔ indices[a]? = some i := by grind
+
+namespace IndexMap
+
+variable {α : Type u} {β : Type v} [BEq α] [Hashable α]
+variable {m : IndexMap α β} {a : α} {b : β} {i : Nat}
+
+@[inline] def size (m : IndexMap α β) : Nat :=
+  m.values.size
+
+@[local grind =] private theorem size_keys : m.keys.size = m.size := m.size_keys'
+
+def emptyWithCapacity (capacity := 8) : IndexMap α β where
+  indices := HashMap.emptyWithCapacity capacity
+  keys := Array.emptyWithCapacity capacity
+  values := Array.emptyWithCapacity capacity
+
+instance : EmptyCollection (IndexMap α β) where
+  emptyCollection := emptyWithCapacity
+
+instance : Inhabited (IndexMap α β) where
+  default := ∅
+
+@[inline] def contains (m : IndexMap α β)
+    (a : α) : Bool :=
+  m.indices.contains a
+
+instance : Membership α (IndexMap α β) where
+  mem m a := a ∈ m.indices
+
+instance {m : IndexMap α β} {a : α} : Decidable (a ∈ m) :=
+  inferInstanceAs (Decidable (a ∈ m.indices))
+
+@[local grind =] private theorem mem_indices_of_mem {m : IndexMap α β} {a : α} :
+    a ∈ m ↔ a ∈ m.indices := Iff.rfl
+
+@[inline] def findIdx? (m : IndexMap α β) (a : α) : Option Nat := m.indices[a]?
+
+@[inline] def findIdx (m : IndexMap α β) (a : α) (h : a ∈ m := by get_elem_tactic) : Nat := m.indices[a]
+
+@[inline] def getIdx? (m : IndexMap α β) (i : Nat) : Option β := m.values[i]?
+
+@[inline] def getIdx (m : IndexMap α β) (i : Nat) (h : i < m.size := by get_elem_tactic) : β :=
+  m.values[i]
+
+variable [LawfulBEq α] [LawfulHashable α]
+
+attribute [local grind _=_] IndexMap.WF
+
+private theorem getElem_indices_lt {h : a ∈ m} : m.indices[a] < m.size := by
+  have : m.indices[a]? = some m.indices[a] := by grind
+  grind
+
+grind_pattern getElem_indices_lt => m.indices[a]
+
+attribute [local grind] size
+
+instance : GetElem? (IndexMap α β) α β (fun m a => a ∈ m) where
+  getElem m a h := m.values[m.indices[a]'h]
+  getElem? m a := m.indices[a]?.bind (fun i => (m.values[i]?))
+  getElem! m a := m.indices[a]?.bind (fun i => (m.values[i]?)) |>.getD default
+
+@[local grind =] private theorem getElem_def (m : IndexMap α β) (a : α) (h : a ∈ m) : m[a] = m.values[m.indices[a]'h] := rfl
+@[local grind =] private theorem getElem?_def (m : IndexMap α β) (a : α) :
+    m[a]? = m.indices[a]?.bind (fun i => (m.values[i]?)) := rfl
+@[local grind =] private theorem getElem!_def [Inhabited β] (m : IndexMap α β) (a : α) :
+    m[a]! = (m.indices[a]?.bind (fun i => (m.values[i]?))).getD default := rfl
+
+instance : LawfulGetElem (IndexMap α β) α β (fun m a => a ∈ m) where
+  getElem?_def := by grind
+  getElem!_def := by grind
+
+@[inline] def insert [LawfulBEq α] (m : IndexMap α β) (a : α) (b : β) :
+    IndexMap α β :=
+  match h : m.indices[a]? with
+  | some i =>
+    { indices := m.indices
+      keys := m.keys.set i a
+      values := m.values.set i b }
+  | none =>
+    { indices := m.indices.insert a m.size
+      keys := m.keys.push a
+      values := m.values.push b }
+
+/-! ### Verification theorems -/
+
+attribute [local grind] getIdx findIdx insert
+
+example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
+    (m.insert a b)[a'] = if h' : a' == a then b else m[a'] := by
+  grind -offset -ring -linarith -cutsat =>
+    instantiate only [= getElem_def, insert]
+    cases #f590
+    next =>
+      cases #ffdf
+      next => sorry
+      next =>
+        instantiate only
+        instantiate only [= HashMap.getElem_insert]
+        instantiate only [= size]
+        instantiate only [= Array.getElem_push, = mem_indices_of_mem]
+    next => sorry
+
+example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
+    (m.insert a b)[a'] = if h' : a' == a then b else m[a'] := by
+  grind -offset -ring -linarith -cutsat =>
+    instantiate only [= getElem_def, insert]
+    cases #f590
+    next =>
+      cases #ffdf
+      next => sorry
+      next =>
+        instantiate only
+        instantiate only [= HashMap.getElem_insert]
+        instantiate only [= size]
+        instantiate only [= mem_indices_of_mem, = Array.getElem_push]
+    next => sorry