[clang] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

1 files changed, 2 insertions, 2 deletions

diff --git a/clang/lib/Lex/HeaderMap.cpp b/clang/lib/Lex/HeaderMap.cpp
index 0001fc3..2512552 100644
--- a/clang/lib/Lex/HeaderMap.cpp
+++ b/clang/lib/Lex/HeaderMap.cpp
@@ -151,7 +151,7 @@ Optional<StringRef> HeaderMapImpl::getString(unsigned StrTabIdx) const {
 
   // Check for invalid index.
   if (StrTabIdx >= FileBuffer->getBufferSize())
-    return None;
+    return std::nullopt;
 
   const char *Data = FileBuffer->getBufferStart() + StrTabIdx;
   unsigned MaxLen = FileBuffer->getBufferSize() - StrTabIdx;
@@ -159,7 +159,7 @@ Optional<StringRef> HeaderMapImpl::getString(unsigned StrTabIdx) const {
 
   // Check whether the buffer is null-terminated.
   if (Len == MaxLen && Data[Len - 1])
-    return None;
+    return std::nullopt;
 
   return StringRef(Data, Len);
 }