[clang-tools-extra] 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

4 files changed, 8 insertions, 8 deletions

diff --git a/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h b/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h
index fc21eff35792..ac911be45de9 100644
--- a/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h
+++ b/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h
@@ -222,7 +222,7 @@ private:
       Word KeyMask = Word(1) << (Key % WordBits);
       unsigned KeyWord = Key / WordBits;
       if ((HasValue[KeyWord] & KeyMask) == 0)
-        return llvm::None;
+        return std::nullopt;
       // Count the number of values since the checkpoint.
       Word BelowKeyMask = KeyMask - 1;
       unsigned CountSinceCheckpoint =
diff --git a/clang-tools-extra/pseudo/lib/DirectiveTree.cpp b/clang-tools-extra/pseudo/lib/DirectiveTree.cpp
index c9e0198227fa..2d0199c63099 100644
--- a/clang-tools-extra/pseudo/lib/DirectiveTree.cpp
+++ b/clang-tools-extra/pseudo/lib/DirectiveTree.cpp
@@ -92,7 +92,7 @@ private:
         Tree->Chunks.push_back(std::move(Directive));
       }
     }
-    return None;
+    return std::nullopt;
   }
 
   // Parse the rest of a conditional section, after seeing the If directive.
@@ -292,7 +292,7 @@ private:
     case clang::tok::pp_else:
       return true;
     default: // #ifdef etc
-      return llvm::None;
+      return std::nullopt;
     }
 
     const auto &Tokens = Code.tokens(Dir.Tokens);
@@ -301,11 +301,11 @@ private:
     const Token &Value = Name.nextNC();
     // Does the condition consist of exactly one token?
     if (&Value >= Tokens.end() || &Value.nextNC() < Tokens.end())
-      return llvm::None;
+      return std::nullopt;
     return llvm::StringSwitch<llvm::Optional<bool>>(Value.text())
         .Cases("true", "1", true)
         .Cases("false", "0", false)
-        .Default(llvm::None);
+        .Default(std::nullopt);
   }
 
   const TokenStream &Code;
diff --git a/clang-tools-extra/pseudo/lib/Forest.cpp b/clang-tools-extra/pseudo/lib/Forest.cpp
index 131dd4dca839..d24a90fd1fe0 100644
--- a/clang-tools-extra/pseudo/lib/Forest.cpp
+++ b/clang-tools-extra/pseudo/lib/Forest.cpp
@@ -167,12 +167,12 @@ std::string ForestNode::dumpRecursive(const Grammar &G,
             LineDec.Subsequent = "│ ";
           }
           Dump(Children[I], P->kind() == Sequence ? EndOfElement(I) : End,
-               llvm::None, LineDec);
+               std::nullopt, LineDec);
         }
         LineDec.Prefix.resize(OldPrefixSize);
       };
   LineDecoration LineDec;
-  Dump(this, KEnd, llvm::None, LineDec);
+  Dump(this, KEnd, std::nullopt, LineDec);
   return Result;
 }
 
diff --git a/clang-tools-extra/pseudo/lib/grammar/Grammar.cpp b/clang-tools-extra/pseudo/lib/grammar/Grammar.cpp
index 19fefac206b7..8c1338cff037 100644
--- a/clang-tools-extra/pseudo/lib/grammar/Grammar.cpp
+++ b/clang-tools-extra/pseudo/lib/grammar/Grammar.cpp
@@ -51,7 +51,7 @@ llvm::Optional<SymbolID> Grammar::findNonterminal(llvm::StringRef Name) const {
       [&](const GrammarTable::Nonterminal &X) { return X.Name < Name; });
   if (It != T->Nonterminals.end() && It->Name == Name)
     return It - T->Nonterminals.begin();
-  return llvm::None;
+  return std::nullopt;
 }
 
 std::string Grammar::dumpRule(RuleID RID) const {