13 lines
485 B
Text
13 lines
485 B
Text
/-
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Copyright (c) 2022 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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-/
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prelude
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import Init.SimpLemmas
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instance [BEq α] [BEq β] [LawfulBEq α] [LawfulBEq β] : LawfulBEq (α × β) where
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eq_of_beq {a b} (h : a.1 == b.1 && a.2 == b.2) := by
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cases a; cases b
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refine congr (congrArg _ (eq_of_beq ?_)) (eq_of_beq ?_) <;> simp_all
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rfl {a} := by cases a; simp [BEq.beq, LawfulBEq.rfl]
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