From c4f5a5e8637543f16d4b3b191b1aba32c650f1f3 Mon Sep 17 00:00:00 2001
From: Justin Bogner <mail@justinbogner.com>
Date: Fri, 20 Feb 2015 07:28:28 +0000
Subject: [PATCH] Disallow implicit conversions from None to integer types

This fixes an error introduced in r228934 where None was converted to
an int instead of the int being converted to an Optional as intended.
We make that sort of mistake a compile error by changing NoneType into
a scoped enum.

Finally, provide a static NoneType called None to avoid forcing all
users to spell it NoneType::None.

llvm-svn: 229980
---
 llvm/include/llvm/ADT/None.h             | 5 ++---
 llvm/lib/ProfileData/CoverageMapping.cpp | 8 ++++++--
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/ADT/None.h b/llvm/include/llvm/ADT/None.h
index 5793bd2faef4..c78db78597cc 100644
--- a/llvm/include/llvm/ADT/None.h
+++ b/llvm/include/llvm/ADT/None.h
@@ -19,9 +19,8 @@
 namespace llvm {
 /// \brief A simple null object to allow implicit construction of Optional<T>
 /// and similar types without having to spell out the specialization's name.
-enum NoneType {
-  None
-};
+enum class NoneType { None };
+static NoneType None;
 }
 
 #endif
diff --git a/llvm/lib/ProfileData/CoverageMapping.cpp b/llvm/lib/ProfileData/CoverageMapping.cpp
index a124d792e875..da619e1bf9f8 100644
--- a/llvm/lib/ProfileData/CoverageMapping.cpp
+++ b/llvm/lib/ProfileData/CoverageMapping.cpp
@@ -361,7 +361,9 @@ static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
       IsNotExpandedFile[CR.ExpandedFileID] = false;
   IsNotExpandedFile &= FilenameEquivalence;
   int I = IsNotExpandedFile.find_first();
-  return I != -1 ? I : None;
+  if (I == -1)
+    return None;
+  return I;
 }
 
 static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
@@ -370,7 +372,9 @@ static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
     if (CR.Kind == CounterMappingRegion::ExpansionRegion)
       IsNotExpandedFile[CR.ExpandedFileID] = false;
   int I = IsNotExpandedFile.find_first();
-  return I != -1 ? I : None;
+  if (I == -1)
+    return None;
+  return I;
 }
 
 /// Sort a nested sequence of regions from a single file.