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).
46 lines
1.2 KiB
Text
46 lines
1.2 KiB
Text
set_option pp.mvars false
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/--
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error: type mismatch
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congrArg ?_ (congrArg ?_ ?_)
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has type
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?_ (?_ ?_) = ?_ (?_ ?_)
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but is expected to have type
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OfNat.ofNat 0 = OfNat.ofNat 1
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-/
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#guard_msgs in
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theorem ex1 : (@OfNat.ofNat Nat 0 Zero.toOfNat0) = @OfNat.ofNat Nat 1 One.toOfNat1 := by
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refine congrArg _ (congrArg _ ?_)
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rfl
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/--
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error: tactic 'apply' failed, could not unify the conclusion of `@congrArg`
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?_ ?_ = ?_ ?_
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with the goal
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OfNat.ofNat 0 = OfNat.ofNat 1
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Note: The full type of `@congrArg` is
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∀ {α : Sort _} {β : Sort _} {a₁ a₂ : α} (f : α → β), a₁ = a₂ → f a₁ = f a₂
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⊢ OfNat.ofNat 0 = OfNat.ofNat 1
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-/
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#guard_msgs in
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example : (@OfNat.ofNat Nat 0 Zero.toOfNat0) = @OfNat.ofNat Nat 1 One.toOfNat1 := by
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apply congrArg
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apply congrArg
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apply rfl
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/--
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error: tactic 'apply' failed, could not unify the conclusion of `@congrArg`
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?_ ?_ = ?_ ?_
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with the goal
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OfNat.ofNat 0 = OfNat.ofNat 1
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Note: The full type of `@congrArg` is
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∀ {α : Sort _} {β : Sort _} {a₁ a₂ : α} (f : α → β), a₁ = a₂ → f a₁ = f a₂
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⊢ OfNat.ofNat 0 = OfNat.ofNat 1
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-/
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#guard_msgs in
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theorem ex2 : (@OfNat.ofNat Nat 0 Zero.toOfNat0) = @OfNat.ofNat Nat 1 One.toOfNat1 := by
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apply congrArg
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apply congrArg
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apply rfl
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