Simplify some code in SourceFile, NFC

include/swift/AST/Module.h

@@ -1073,23 +1073,22 @@ public:
   }
 
   std::vector<Token> &getTokenVector() {
-    assert(EnabledAndAllCorrectedTokens.first && "Disabled");
-    return EnabledAndAllCorrectedTokens.second;
+    assert(pAllCorrectedTokens && "Disabled");
+    return *pAllCorrectedTokens;
   }
 
   ArrayRef<Token> getAllTokens() const {
-    assert(EnabledAndAllCorrectedTokens.first && "Disabled");
-    return EnabledAndAllCorrectedTokens.second;
+    assert(pAllCorrectedTokens && "Disabled");
+    return *pAllCorrectedTokens;
   }
 
   bool shouldKeepTokens() const {
-    return EnabledAndAllCorrectedTokens.first;
+    return (bool)pAllCorrectedTokens;
   }
 
 private:
-  /// Whether the SourceFile instance opts to collect underlying tokens and
-  /// the vector containing these tokens if so.
-  std::pair<bool, std::vector<Token>> EnabledAndAllCorrectedTokens;
+  /// If not null, the pointee vector should contain tokens of this source file.
+  std::unique_ptr<std::vector<Token>> pAllCorrectedTokens;
 };
 
 

lib/AST/Module.cpp

@@ -1325,8 +1325,7 @@ SourceFile::SourceFile(ModuleDecl &M, SourceFileKind K,
                        bool KeepTokens)
   : FileUnit(FileUnitKind::Source, M),
     BufferID(bufferID ? *bufferID : -1),
-    Kind(K),
-    EnabledAndAllCorrectedTokens(KeepTokens, std::vector<Token>()) {
+    Kind(K) {
   M.getASTContext().addDestructorCleanup(*this);
   performAutoImport(*this, ModImpKind);
 
@@ -1335,6 +1334,9 @@ SourceFile::SourceFile(ModuleDecl &M, SourceFileKind K,
     assert(!problem && "multiple main files?");
     (void)problem;
   }
+  if (KeepTokens) {
+    pAllCorrectedTokens.reset(new std::vector<Token>());
+  }
 }
 
 SourceFile::~SourceFile() {}