/-
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura, Jeremy Avigad

The sum type, aka disjoint union.
-/
prelude
import init.logic
set_option new_elaborator true

notation A ⊕ B := sum A B
variables {A B : Type}

attribute [instance]
protected definition is_inhabited_left [h : inhabited A] : inhabited (A ⊕ B) :=
inhabited.mk (sum.inl (default A))

attribute [instance]
protected definition is_inhabited_right [h : inhabited B] : inhabited (A ⊕ B) :=
inhabited.mk (sum.inr (default B))