06ac472859
This PR extends the procedure behind `inferInstanceAs`/`def ... deriving` to continue recursion through the class graph even when a (local) instance to wrap was found in order to re-use already-wrapped instance of subclasses.
141 lines
3.3 KiB
Text
141 lines
3.3 KiB
Text
module
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class C (α : Type) where
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c : α → α
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/-! Trivial data wrapper -/
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axiom I : Type
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instance : C I where
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c x := x
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def D := I
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instance : C D := inferInstanceAs (C I)
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-- We can still use it as an `inferInstance` synonym in the old mode
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set_option backward.inferInstanceAs.wrap false in
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/-- info: «inferInstanceAs» (C D) : C D -/
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#guard_msgs in
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#check inferInstanceAs (C D)
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/--
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info: @[implicit_reducible] private def instCD : C D :=
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{ c := instCD._aux_1 }
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-/
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#guard_msgs in
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#print instCD
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/--
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info: private def instCD._aux_1 : D → D :=
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fun x => x
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-/
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#guard_msgs in
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#print instCD._aux_1
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/-! Irreducible instances are wrapped as is. -/
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axiom I2 : Type
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@[instance] opaque instCI2 : C I2 := { c := fun x => x }
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def D2 := I2
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instance : C D2 := inferInstanceAs (C I2)
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/--
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info: @[implicit_reducible] private def instCD2 : C D2 :=
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instCD2._aux_1
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-/
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#guard_msgs in
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#print instCD2
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/--
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info: private def instCD2._aux_1 : C D2 :=
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instCI2
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-/
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#guard_msgs in
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#print instCD2._aux_1
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/-! Flattened inheritance test. -/
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class Base (α : Type) where
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b : α
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class Foo (α : Type) extends Base α where
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a : α
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class Bar (α : Type) extends Base α where
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c : α
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class FooBar (α : Type) extends Foo α, Bar α
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instance : FooBar Nat where
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a := 0
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b := 1
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c := 2
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def MyNat := Nat
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deriving Foo, Bar, FooBar
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theorem zou : instFooBarMyNat.toBar = instBarMyNat := by
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with_reducible_and_instances rfl
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/-! Non-constructor instances should be used as is. -/
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@[macro_inline, implicit_reducible]
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def dite' {α : Sort u} (c : Prop) [h : Decidable c] (t : c → α) (e : Not c → α) : α :=
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h.casesOn e t
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instance Nat.decLe' (n m : @& Nat) : Decidable (LE.le n m) :=
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dite' (Eq (Nat.ble n m) true) (fun h => isTrue (Nat.le_of_ble_eq_true h)) (fun h => isFalse (Nat.not_le_of_not_ble_eq_true h))
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#guard_msgs in
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instance (x y : BitVec w) : Decidable (LE.le x y) :=
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(inferInstance : Decidable (LE.le x.toNat y.toNat))
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instance (x y : BitVec w) : Decidable (LE.le x y) :=
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inferInstanceAs (Decidable (LE.le x.toNat y.toNat))
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/-! Universes can be introduced by synth and need to be unified with the expected type properly. -/
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structure MyStruct where
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x : PUnit.{u + 1} := ⟨⟩
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y : PUnit.{v + 1} := ⟨⟩
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instance : Zero MyStruct.{u, max u v} := ⟨{}⟩
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instance : Zero MyStruct.{u, max u v} := inferInstanceAs <| Zero MyStruct.{u, max u v}
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/-! Test reusing subinstances not encountered directly. -/
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class Base2 (α : Type) where
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a : α
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class Main0 (α : Type) extends Base2 α where
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b : α
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class Main1 (α : Type) extends Base2 α where
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c : α
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class Super (α : Type) extends Main0 α, Main1 α where
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def MyCopy (α : Type) : Type := α
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instance iBase2 (α : Type) [Base2 α] : Base2 (MyCopy α) :=
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inferInstanceAs <| Base2 α
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instance iMain0 (α : Type) [Main0 α] : Main0 (MyCopy α) :=
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inferInstanceAs <| Main0 α
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instance iMain1 (α : Type) [Main1 α] : Main1 (MyCopy α) :=
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inferInstanceAs <| Main1 α
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instance iSuper (α : Type) [Super α] : Super (MyCopy α) :=
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inferInstanceAs <| Super α
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example (α : Type) [Super α] :
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(iSuper α).toMain1 = iMain1 α := by
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with_reducible_and_instances rfl
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/--
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info: @[implicit_reducible] private def iSuper : (α : Type) → [Super α] → Super (MyCopy α) :=
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fun α [Super α] => { toMain0 := iMain0 α, c := Main1.c }
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-/
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#guard_msgs in
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#print iSuper
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