8424ddbb3e
This PR improves the “expected type mismatch” error message by omitting the type's types when they are defeq, and putting them into separate lines when not. I found it rather tediuos to parse the error message when the expected type is long, because I had to find the `:` in the middle of a large expression somewhere. Also, when both are of sort `Prop` or `Type` it doesn't add much value to print the sort (and it’s only one hover away anyways).
60 lines
1.2 KiB
Text
60 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
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of sort `Type 1` but is expected to have type
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Prop
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of sort `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
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of sort `Type 1` but is expected to have type
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Prop
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of sort `Type`
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-/
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#guard_msgs in #reduce elab_1eq1
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end
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