31 lines
1,015 B
Text
31 lines
1,015 B
Text
/-
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This is an annoyingly unhelpful error message that I see all the time.
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An exact line number would help a lot, but even so it would be great
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to replace the `⟨...⟩` with the actual term in question.
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[Leo]: The bad position is due the transition to the new elaborator.
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The new frontend produces the correct position.
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Note that, the new frontend reports an error at `⟨4⟩`. This is the correct
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position, and it is not possible to infer anything about the expected type since
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`x4` is not used anywhere. So, the error message is the best we can get.
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There is no actual term to replace. If we comment the line `let x4 := ...`,
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the new elaborator succeeds.
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-/
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structure Foo := (n : Nat)
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def Foo.sum (xs : List Foo) : Foo :=
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xs.foldl (λ s x => ⟨s.n + x.n⟩) ⟨0⟩
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#check
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let x1 := ⟨1⟩;
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let x2 := ⟨2⟩;
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let x3 := ⟨3⟩;
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let x4 := ⟨4⟩;
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let x5 := ⟨5⟩;
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let x6 := ⟨6⟩;
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Foo.sum [x1, x2, x3, x5, x6]
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/-
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error: invalid constructor ⟨...⟩, expected type is not an inductive type
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?m_1
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-/
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