From bebd010673218c252b43aede96d3fc5717519dc7 Mon Sep 17 00:00:00 2001
From: Max Moiseev <moiseev@apple.com>
Date: Tue, 27 Jun 2017 14:45:15 -0700
Subject: [PATCH] [NOT FOR MERGE][stdlib] Adding a variant of ??, with a Never
 returning closure

---
 stdlib/public/core/Optional.swift | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/stdlib/public/core/Optional.swift b/stdlib/public/core/Optional.swift
index b694cdb91ee7f..a1bd5a83535b8 100644
--- a/stdlib/public/core/Optional.swift
+++ b/stdlib/public/core/Optional.swift
@@ -675,6 +675,17 @@ public func ?? <T>(optional: T?, defaultValue: @autoclosure () throws -> T?)
   }
 }
 
+@_transparent
+public func ?? <T>(optional: T?, defaultValue: @autoclosure () throws -> Never)
+    rethrows -> T {
+  switch optional {
+  case .some(let value):
+    return value
+  case .none:
+    try defaultValue()
+  }
+}
+
 extension Optional {
 
   @available(*, unavailable, renamed: "none")