1//===-- None.h - Simple null value for implicit construction ------*- C++ -*-=//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file provides None, an enumerator for use in implicit constructors
11// of various (usually templated) types to make such construction more
12// terse.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_ADT_NONE_H
17#define LLVM_ADT_NONE_H
18
19namespace llvm {
20/// A simple null object to allow implicit construction of Optional<T>
21/// and similar types without having to spell out the specialization's name.
22// (constant value 1 in an attempt to workaround MSVC build issue... )
23enum class NoneType { None = 1 };
24const NoneType None = NoneType::None;
25}
26
27#endif
28