5f4e6a86d5
This PR updates the formatting of, and adds explanations for, "unknown identifier" errors as well as "failed to infer type" errors for binders and definitions. It attempts to ameliorate some of the confusion encountered in #1592 by modifying the wording of the "header is elaborated before body is processed" note and adding further discussion and examples of this behavior in the corresponding error explanation.
99 lines
2.6 KiB
Text
99 lines
2.6 KiB
Text
mutual
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def f : Nat → α → α → α
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| 0, a, b => a
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| n, a, b => g a n b |>.1
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termination_by n _ _ => (n, 2)
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decreasing_by
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apply Prod.Lex.right
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decide
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def g : α → Nat → α → (α × α)
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| a, 0, b => (a, b)
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| a, n, b => (h a b n, a)
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termination_by _ n _ => (n, 1)
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decreasing_by
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apply Prod.Lex.right
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decide
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def h : α → α → Nat → α
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| a, b, 0 => b
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| a, b, n+1 => f n a b
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termination_by _ _ n => (n, 0)
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decreasing_by
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apply Prod.Lex.left
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apply Nat.lt_succ_self
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end
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/-- info: 'a' -/
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#guard_msgs in
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#eval f 5 'a' 'b'
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/-- info: @f.eq_1 : ∀ {α : Type u_1} (x x_1 : α), f 0 x x_1 = x -/
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#guard_msgs in
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#check @f.eq_1
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/--
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info: @f.eq_2 : ∀ {α : Type u_1} (x : Nat) (x_1 x_2 : α), (x = 0 → False) → f x x_1 x_2 = (g x_1 x x_2).fst
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-/
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#guard_msgs in
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#check @f.eq_2
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/--
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info: @f.eq_def : ∀ {α : Type u_1} (x : Nat) (x_1 x_2 : α),
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f x x_1 x_2 =
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match x, x_1, x_2 with
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| 0, a, b => a
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| n, a, b => (g a n b).fst
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-/
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#guard_msgs in
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#check @f.eq_def
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/-- error: Unknown identifier `f.eq_3` -/
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#guard_msgs in
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#check @f.eq_3
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/-- info: @h.eq_1 : ∀ {α : Type u_1} (x x_1 : α), h x x_1 0 = x_1 -/
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#guard_msgs in
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#check @h.eq_1
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/-- info: @h.eq_2 : ∀ {α : Type u_1} (x x_1 : α) (n : Nat), h x x_1 n.succ = f n x x_1 -/
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#guard_msgs in
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#check @h.eq_2
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/--
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info: @h.eq_def : ∀ {α : Type u_1} (x x_1 : α) (x_2 : Nat),
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h x x_1 x_2 =
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match x, x_1, x_2 with
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| a, b, 0 => b
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| a, b, n.succ => f n a b
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-/
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#guard_msgs in
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#check @h.eq_def
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/-- error: Unknown identifier `h.eq_3` -/
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#guard_msgs in
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#check @h.eq_3
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/--
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info: f._mutual.eq_def.{u_1} {α : Type u_1}
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(x✝ : (_ : Nat) ×' (_ : α) ×' α ⊕' (_ : α) ×' (_ : Nat) ×' α ⊕' (_ : α) ×' (_ : α) ×' Nat) :
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f._mutual x✝ =
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PSum.casesOn x✝
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(fun _x =>
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PSigma.casesOn _x fun a a_1 =>
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PSigma.casesOn a_1 fun a_2 a_3 =>
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match a, a_2, a_3 with
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| 0, a, b => a
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| n, a, b => (f._mutual (PSum.inr (PSum.inl ⟨a, ⟨n, b⟩⟩))).fst)
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fun _x =>
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PSum.casesOn _x
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(fun _x =>
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PSigma.casesOn _x fun a a_1 =>
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PSigma.casesOn a_1 fun a_2 a_3 =>
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match a, a_2, a_3 with
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| a, 0, b => (a, b)
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| a, n, b => (f._mutual (PSum.inr (PSum.inr ⟨a, ⟨b, n⟩⟩)), a))
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fun _x =>
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PSigma.casesOn _x fun a a_1 =>
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PSigma.casesOn a_1 fun a_2 a_3 =>
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match a, a_2, a_3 with
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| a, b, 0 => b
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| a, b, n.succ => f._mutual (PSum.inl ⟨n, ⟨a, b⟩⟩)
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-/
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#guard_msgs in
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#check f._mutual.eq_def
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