995fa4766b
This PR refines the new wording of the "application type mismatch" error message to avoid ambiguity in references to the "final" argument in a subexpression that may be followed by additional arguments. It does so by replacing "final" with "last," rephrasing the message so that this adjective modifies the argument itself rather than the word "argument," and only displaying this wording when two arguments could be confused (determined by expression equality). These changes were motivated by a report that in cases where a function application `f a b c` fails to elaborate because `b` is incorrectly typed, the existing error message's reference to `b` being the "final" argument in the application `f a b` may create confusion because it is not the final argument in the full application expression.
58 lines
1.2 KiB
Text
58 lines
1.2 KiB
Text
import Lean
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/-- info: And.intro {a b : Prop} (left : a) (right : b) : a ∧ b -/
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#guard_msgs in
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#check And.intro
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/--
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info: @Or.rec : ∀ {a b : Prop} {motive : a ∨ b → Prop},
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(∀ (h : a), motive ⋯) → (∀ (h : b), motive ⋯) → ∀ (t : a ∨ b), motive t
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-/
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#guard_msgs in
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#check @Or.rec
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/-- info: Eq.{u_1} {α : Sort u_1} : α → α → Prop -/
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#guard_msgs in
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#check Eq
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/--
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info: @Eq.rec : {α : Sort u_2} →
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{a : α} → {motive : (a_1 : α) → a = a_1 → Sort u_1} → motive a ⋯ → {a_1 : α} → (t : a = a_1) → motive a_1 t
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-/
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#guard_msgs in
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#check @Eq.rec
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/-!
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The `#check` command also typechecks the result to help users debug buggy elaborators.
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-/
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section
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open Lean
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def expr_1eq1 : Expr := mkApp3 (.const ``Eq [0]) (.const ``Nat []) (mkNatLit 1) (mkNatLit 1)
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elab "elab_1eq1" : term => return expr_1eq1
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/--
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error: Application type mismatch: In the application
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@Eq Nat
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the argument
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Nat
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has type
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Type : Type 1
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but is expected to have type
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Prop : Type
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-/
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#guard_msgs in #check elab_1eq1
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/--
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error: Application type mismatch: In the application
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@Eq Nat
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the argument
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Nat
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has type
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Type : Type 1
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but is expected to have type
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Prop : Type
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-/
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#guard_msgs in #reduce elab_1eq1
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end
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