feat: add lemmas for DHashMap/HashMap/HashSet about emptyWithCapacity/empty (#11223)

This PR adds missing lemmas relating `emptyWithCapacity`/`empty` and
`toList`/`keys`/`values` for `DHashMap`/`HashMap`/`HashSet`.

Author: wkrozowski

src/Std/Data/DHashMap/Internal/RawLemmas.lean

@@ -75,6 +75,22 @@ theorem size_emptyWithCapacity {c} : (emptyWithCapacity c : Raw₀ α β).1.size
 theorem isEmpty_eq_size_eq_zero : m.1.isEmpty = (m.1.size == 0) := by
   simp [Raw.isEmpty]
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : Raw₀ α β).1.toList = [] := by
+  rw [Raw.toList_eq_toListModel, toListModel_buckets_emptyWithCapacity]
+
+@[simp]
+theorem Const.toList_emptyWithCapacity {c} {β : Type v} : Raw.Const.toList (emptyWithCapacity c : Raw₀ α (fun _ => β)).1 = [] := by
+  rw [Raw.Const.toList_eq_toListModel_map, toListModel_buckets_emptyWithCapacity, List.map_nil]
+
+@[simp]
+theorem keys_emptyWithCapacity {c} : (emptyWithCapacity c : Raw₀ α β).1.keys = [] := by
+  rw [Raw.keys_eq_keys_toListModel, toListModel_buckets_emptyWithCapacity, List.keys_nil]
+
+@[simp]
+theorem Const.values_emptyWithCapacity {c} {β : Type v} : (emptyWithCapacity c : Raw₀ α (fun _ => β)).1.values = [] := by
+  rw [Raw.values_eq_values_toListModel, toListModel_buckets_emptyWithCapacity, List.values_nil]
+
 variable [BEq α] [Hashable α]
 
 /-- Internal implementation detail of the hash map -/

src/Std/Data/DHashMap/Internal/WF.lean

@@ -131,6 +131,11 @@ theorem foldRev_cons_key {l : Raw α β} {acc : List α} :
       List.keys (toListModel l.buckets) ++ acc := by
   rw [foldRev_cons_apply, keys_eq_map]
 
+theorem foldRev_cons_value {β : Type v} {l : Raw α (fun _ => β)} {acc : List β} :
+    Raw.Internal.foldRev (fun acc _ v => v :: acc) acc l =
+      List.values (toListModel l.buckets) ++ acc := by
+  rw [foldRev_cons_apply, values_eq_map]
+
 theorem fold_push {l : Raw α β} {acc : Array ((a : α) × β a)} :
     Raw.fold (fun acc k v => acc.push ⟨k, v⟩) acc l = acc ++ (toListModel l.buckets).toArray := by
   simp [fold_push_apply]
@@ -207,6 +212,10 @@ theorem keys_eq_keys_toListModel {m : Raw α β} :
     m.keys = List.keys (toListModel m.buckets) := by
   simp [Raw.keys, foldRev_cons_key, keys_eq_map]
 
+theorem values_eq_values_toListModel {β : Type v}  {m : Raw α (fun _ => β)} :
+    m.values = List.values (toListModel m.buckets) := by
+  simp [Raw.values, foldRev_cons_value, values_eq_map]
+
 theorem keysArray_eq_toArray_keys_toListModel {m : Raw α β} :
     m.keysArray = (List.keys (toListModel m.buckets)).toArray := by
   simp [Raw.keysArray, fold_push_key]

src/Std/Data/DHashMap/Lemmas.lean

@@ -148,6 +148,38 @@ theorem size_empty : (∅ : DHashMap α β).size = 0 :=
 
 theorem isEmpty_eq_size_eq_zero : m.isEmpty = (m.size == 0) := (rfl)
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : DHashMap α β).toList = [] :=
+  Raw₀.toList_emptyWithCapacity
+
+@[simp]
+theorem toList_empty : (∅ : DHashMap α β).toList = [] :=
+  toList_emptyWithCapacity
+
+@[simp]
+theorem Const.toList_emptyWithCapacity {c} {β : Type v}: Const.toList (emptyWithCapacity c : DHashMap α (fun _ => β)) = [] :=
+  Raw₀.Const.toList_emptyWithCapacity
+
+@[simp]
+theorem Const.toList_empty {β : Type v} : Const.toList (∅ : DHashMap α (fun _ => β)) = [] :=
+  Const.toList_emptyWithCapacity
+
+@[simp]
+theorem keys_emptyWithCapacity {c} : (emptyWithCapacity c : DHashMap α β).keys = [] :=
+  Raw₀.keys_emptyWithCapacity
+
+@[simp]
+theorem keys_empty : (∅ : DHashMap α β).keys = [] :=
+  keys_emptyWithCapacity
+
+@[simp]
+theorem Const.values_emptyWithCapacity {c} {β : Type v} : (emptyWithCapacity c : DHashMap α (fun _ => β)).values = [] :=
+  Raw₀.Const.values_emptyWithCapacity
+
+@[simp]
+theorem Const.values_empty {β : Type v} : (∅ : DHashMap α (fun _ => β)).values = [] :=
+  Const.values_emptyWithCapacity
+
 @[grind =] theorem size_insert [EquivBEq α] [LawfulHashable α] {k : α} {v : β k} :
     (m.insert k v).size = if k ∈ m then m.size else m.size + 1 :=
   Raw₀.size_insert ⟨m.1, _⟩ m.2

src/Std/Data/DHashMap/RawLemmas.lean

@@ -81,6 +81,38 @@ theorem size_empty : (∅ : Raw α β).size = 0 :=
 theorem isEmpty_eq_size_eq_zero : m.isEmpty = (m.size == 0) := by
   simp [isEmpty]
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : Raw α β).toList = [] := by
+  simp_to_raw using Raw₀.toList_emptyWithCapacity
+
+@[simp]
+theorem Const.toList_emptyWithCapacity {β : Type v} {c} : Const.toList (emptyWithCapacity c : Raw α (fun _ => β)) = [] := by
+  simp_to_raw using Raw₀.Const.toList_emptyWithCapacity
+
+@[simp]
+theorem toList_empty : (∅ : Raw α β).toList = [] :=
+  toList_emptyWithCapacity
+
+@[simp]
+theorem Const.toList_empty {β : Type v} : Const.toList (∅ : Raw α (fun _ => β)) = [] :=
+  Const.toList_emptyWithCapacity
+
+@[simp]
+theorem keys_emptyWithCapacity {c} : (emptyWithCapacity c : Raw α β).keys = [] := by
+    simp_to_raw using Raw₀.keys_emptyWithCapacity
+
+@[simp]
+theorem keys_empty : (∅ : Raw α β).keys = [] :=
+  keys_emptyWithCapacity
+
+@[simp]
+theorem Const.values_emptyWithCapacity {c} {β : Type v} : (emptyWithCapacity c : Raw α (fun _ => β)).values = [] := by
+  simp_to_raw using Raw₀.Const.values_emptyWithCapacity
+
+@[simp]
+theorem Const.values_empty {β : Type v} : (∅ : Raw α (fun _ => β)).values = [] :=
+  Const.values_emptyWithCapacity
+
 variable [BEq α] [Hashable α]
 
 @[simp, grind =]

src/Std/Data/HashMap/Lemmas.lean

@@ -147,6 +147,30 @@ theorem size_empty : (∅ : HashMap α β).size = 0 :=
 theorem isEmpty_eq_size_eq_zero : m.isEmpty = (m.size == 0) :=
   DHashMap.isEmpty_eq_size_eq_zero
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : HashMap α β).toList = [] :=
+  DHashMap.Const.toList_emptyWithCapacity
+
+@[simp]
+theorem toList_empty : (∅ : HashMap α β).toList = [] :=
+  toList_emptyWithCapacity
+
+@[simp]
+theorem keys_emptyWithCapacity {c} : (emptyWithCapacity c : HashMap α β).keys = [] :=
+  DHashMap.keys_emptyWithCapacity
+
+@[simp]
+theorem keys_empty : (∅ : HashMap α β).keys = [] :=
+  keys_emptyWithCapacity
+
+@[simp]
+theorem values_emptyWithCapacity {c} {β : Type v} : (emptyWithCapacity c : HashMap α β).values = [] :=
+  DHashMap.Const.values_emptyWithCapacity
+
+@[simp]
+theorem values_empty {β : Type v} : (∅ : HashMap α β).values = [] :=
+  values_emptyWithCapacity
+
 @[grind =] theorem size_insert [EquivBEq α] [LawfulHashable α] {k : α} {v : β} :
     (m.insert k v).size = if k ∈ m then m.size else m.size + 1 :=
   DHashMap.size_insert

src/Std/Data/HashMap/RawLemmas.lean

@@ -44,6 +44,30 @@ theorem size_empty : (∅ : Raw α β).size = 0 :=
 theorem isEmpty_eq_size_eq_zero : m.isEmpty = (m.size == 0) :=
   DHashMap.Raw.isEmpty_eq_size_eq_zero
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : Raw α β).toList = [] :=
+  DHashMap.Raw.Const.toList_emptyWithCapacity
+
+@[simp]
+theorem toList_empty : (∅ : Raw α β).toList = [] :=
+  toList_emptyWithCapacity
+
+@[simp]
+theorem keys_emptyWithCapacity {c} : (emptyWithCapacity c : Raw α β).keys = [] :=
+  DHashMap.Raw.keys_emptyWithCapacity
+
+@[simp]
+theorem keys_empty : (∅ : Raw α β).keys = [] :=
+  keys_emptyWithCapacity
+
+@[simp]
+theorem values_emptyWithCapacity {c} {β : Type v} : (emptyWithCapacity c : Raw α β).values = [] :=
+  DHashMap.Raw.Const.values_emptyWithCapacity
+
+@[simp]
+theorem values_empty {β : Type v} : (∅ : Raw α β).values = [] :=
+  values_emptyWithCapacity
+
 private theorem ext {m m' : Raw α β} : m.inner = m'.inner → m = m' := by
   cases m; cases m'; rintro rfl; rfl
 

src/Std/Data/HashSet/Lemmas.lean

@@ -151,6 +151,14 @@ theorem size_empty : (∅ : HashSet α).size = 0 :=
 theorem isEmpty_eq_size_eq_zero : m.isEmpty = (m.size == 0) :=
   HashMap.isEmpty_eq_size_eq_zero
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : HashSet α).toList = [] :=
+  HashMap.keys_emptyWithCapacity
+
+@[simp]
+theorem toList_empty : (∅ : HashSet α).toList = [] :=
+  toList_emptyWithCapacity
+
 @[grind =] theorem size_insert [EquivBEq α] [LawfulHashable α] {k : α} :
     (m.insert k).size = if k ∈ m then m.size else m.size + 1 :=
   HashMap.size_insertIfNew

src/Std/Data/HashSet/RawLemmas.lean

@@ -46,6 +46,14 @@ theorem size_empty : (∅ : Raw α).size = 0 :=
 theorem isEmpty_eq_size_eq_zero : m.isEmpty = (m.size == 0) :=
   HashMap.Raw.isEmpty_eq_size_eq_zero
 
+@[simp]
+theorem toList_emptyWithCapacity {c} : (emptyWithCapacity c : Raw α).toList = [] :=
+  HashMap.Raw.keys_emptyWithCapacity
+
+@[simp]
+theorem toList_empty : (∅ : Raw α).toList = [] :=
+  toList_emptyWithCapacity
+
 variable [BEq α] [Hashable α]
 
 @[simp, grind =]

src/Std/Data/Internal/List/Associative.lean

@@ -162,6 +162,12 @@ theorem keys_eq_map {l : List ((a : α) × β a)} :
   | nil => rfl
   | cons => simp [keys, *]
 
+theorem values_eq_map {β : Type v} {l : List ((_ : α) × β)} :
+    values l = l.map (·.2) := by
+  induction l with
+  | nil => rfl
+  | cons => simp [values, *]
+
 theorem getEntry?_eq_some_iff [BEq α] [EquivBEq α] {l : List ((a : α) × β a)} {e} {k}
     (hd : DistinctKeys l) :
     getEntry? k l = some e ↔ k == e.1 ∧ e ∈ l := by
@@ -393,6 +399,7 @@ theorem containsKey_eq_contains_map_fst [BEq α] [PartialEquivBEq α] {l : List
     rw [BEq.comm]
 
 @[simp] theorem keys_nil : keys ([] : List ((a : α) × β a)) = [] := (rfl)
+@[simp] theorem values_nil {β : Type v} : values ([] : List ((_ : α) × β )) = [] := (rfl)
 @[simp] theorem keys_cons {l : List ((a : α) × β a)} {k : α} {v : β k} :
     keys (⟨k, v⟩ :: l) = k :: keys l := (rfl)