leanprover-community / leanprover-community/mathlib4

`apply_fun`: "internal exception: postpone"

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#9,303 2 comments 0 reactions 1 assignee View on GitHub

@kmill is already working on this.

Since Dec 28, 2023.

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Description

import Mathlib.Tactic.ApplyFun

example (a b : Nat) (h : a = b) : False := by
  apply_fun ((·) + 1) at h

I think this is nonsense syntax, I don't understand what the (·) syntax is parsed as, but the error message definitely shouldn't be that

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