From d93a791305d7b323ad5061783ffc850f179b1c40 Mon Sep 17 00:00:00 2001
From: Tudor Bosman <tudorb@fb.com>
Date: Wed, 2 Dec 2015 08:57:22 -0800
Subject: [PATCH] Add Optional::value_type

Summary: Comes in handy, and std::experimental::optional has it.

Reviewed By: yfeldblum

Differential Revision: D2708324

fb-gh-sync-id: 87cdf2449f356d3baf9fb56a608e9c43d8fe79ae
---
 folly/Optional.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/folly/Optional.h b/folly/Optional.h
index 84f5d443..18320090 100644
--- a/folly/Optional.h
+++ b/folly/Optional.h
@@ -91,6 +91,8 @@ class OptionalEmptyException : public std::runtime_error {
 template<class Value>
 class Optional {
  public:
+  typedef Value value_type;
+
   static_assert(!std::is_reference<Value>::value,
                 "Optional may not be used with reference types");
   static_assert(!std::is_abstract<Value>::value,
-- 
2.34.1