1d66ff8231
Fixes a long-standing bug in the the `sorryAx` app unexpander that prevented it from applying. Now `sorry` pretty prints as `sorry`.
95 lines
2.7 KiB
Text
95 lines
2.7 KiB
Text
/-!
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# Dot notation and CoeFun
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https://github.com/leanprover/lean4/issues/1910
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-/
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set_option pp.mvars false
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/-!
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Test that dot notation resolution can see through CoeFun instances.
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-/
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structure Equiv (α β : Sort _) where
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toFun : α → β
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invFun : β → α
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infixl:25 " ≃ " => Equiv
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instance : CoeFun (α ≃ β) fun _ => α → β where
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coe := Equiv.toFun
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structure Foo where
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n : Nat
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def Foo.n' : Foo ≃ Nat := ⟨Foo.n, Foo.mk⟩
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variable (f : Foo)
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/-- info: Foo.n'.toFun f : Nat -/
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#guard_msgs in #check f.n'
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example (f : Foo) : f.n' = f.n := rfl
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/-!
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Fail dot notation if it requires using a named argument from the CoeFun instance.
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-/
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structure F where
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f : Bool → Nat → Nat
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instance : CoeFun F (fun _ => (x : Bool) → (y : Nat) → Nat) where
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coe x := fun (a : Bool) (b : Nat) => x.f a b
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-- Recall CoeFun oddity: it uses the unfolded *value* to figure out parameter names.
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-- That's why this is `a` and `b` rather than `x` and `y`.
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/-- info: fun x => (fun a b => x.f a b) true 2 : F → Nat -/
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#guard_msgs in #check fun (x : F) => x (a := true) (b := 2)
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def Nat.foo : F := { f := fun _ b => b }
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-- Ok:
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/-- info: fun n x => (fun a b => Nat.foo.f a b) x n : Nat → Bool → Nat -/
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#guard_msgs in #check fun (n : Nat) => (Nat.foo · n)
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-- Intentionally fails:
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/--
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error: invalid field notation, function 'Nat.foo' has argument with the expected type
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Nat
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but it cannot be used
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---
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info: fun n => sorry : (n : Nat) → ?_ n
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-/
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#guard_msgs in #check fun (n : Nat) => n.foo
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/-!
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Make sure that dot notation does not use the wrong CoeFun instance.
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The following instances rely on the second one having higher priority,
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so we need to fail completely when the instances would depend on argument values.
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-/
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structure Bar (b : Bool) where
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instance : CoeFun (Bar b) (fun _ => Bar b → Bool) where
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coe := fun _ _ => b
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instance : CoeFun (Bar true) (fun _ => (b : Bool) → Bar b) where
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coe := fun _ _ => {}
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def Bar.bar : Bar true := {}
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/-- info: fun f => (fun x => false) f : Bar false → Bool -/
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#guard_msgs in #check fun (f : Bar false) => Bar.bar false f
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/--
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error: invalid field notation, function 'Bar.bar' does not have argument with type (Bar ...) that can be used, it must be explicit or implicit with a unique name
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---
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info: fun f => sorry : (f : Bar false) → ?_ f
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-/
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#guard_msgs in #check fun (f : Bar false) => f.bar false
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/-- info: fun f => (fun x => false) f : Bar false → Bool -/
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#guard_msgs in #check fun (f : Bar false) => Bar.bar true false f
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/--
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error: invalid field notation, function 'Bar.bar' does not have argument with type (Bar ...) that can be used, it must be explicit or implicit with a unique name
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---
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info: fun f => sorry : (f : Bar false) → ?_ f
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-/
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#guard_msgs in #check fun (f : Bar false) => f.bar true false
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