102e957bb5
The derive handler for `DecidableEq` does not currently support proofs in constructor arguments/structure fields. For example, deriving `DecidableEq` for `Fin n` will fail, because of the field `isLt`. This change checks whether the elements being tested are proofs, and if so, changes the equality proof to just `rfl`.
25 lines
566 B
Text
25 lines
566 B
Text
structure Fin' (n : Nat) where
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val : Nat
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isLt : val < n
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deriving DecidableEq
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#eval
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(Fin'.mk 0 (Nat.lt.step (Nat.lt.base 0)): Fin' 2)
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= (Fin'.mk 0 (Nat.lt.step (Nat.lt.base 0)) : Fin' 2)
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#eval
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(Fin'.mk 0 (Nat.lt.step (Nat.lt.base 0)): Fin' 2)
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= (Fin'.mk 1 (Nat.lt.base 1) : Fin' 2)
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inductive List' (α : Type u) where
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| nil : List' α
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| cons (head : α) (tail : List' α) (h : head = head) : List' α
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deriving DecidableEq
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#eval
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List'.nil.cons 0 rfl
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= List'.nil.cons 0 rfl
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#eval
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List'.nil.cons 0 rfl
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= (List'.nil.cons 0 rfl).cons 1 rfl
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