[Localization] Correct namings and improve comment

Author: HassanElDesouky

include/swift/AST/DiagnosticEngine.h

@@ -1043,7 +1043,7 @@ namespace swift {
 
   public:
     llvm::StringRef diagnosticStringFor(const DiagID id,
-                                        bool printDiagnosticName);
+                                        bool printDiagnosticNames);
 
     /// If there is no clear .dia file for a diagnostic, put it in the one
     /// corresponding to the SourceLoc given here.

include/swift/Localization/LocalizationFormat.h

@@ -156,16 +156,17 @@ class SerializedLocalizationWriter {
 
 class LocalizationProducer {
   /// This allocator will retain localized diagnostic strings containing the
-  /// diagnostic's message and identifier for the duration of compiler
-  /// invocation
+  /// diagnostic's message and identifier as `message [id]` for the duration of
+  /// compiler invocation. This will be used when the frontend flag
+  /// `-debug-diagnostic-names` is used.
   llvm::BumpPtrAllocator localizationAllocator;
   llvm::StringSaver localizationSaver;
-  bool printDiagnosticName;
+  bool printDiagnosticNames;
 
 public:
-  LocalizationProducer(bool printDiagnosticName = false)
+  LocalizationProducer(bool printDiagnosticNames = false)
       : localizationSaver(localizationAllocator),
-        printDiagnosticName(printDiagnosticName) {}
+        printDiagnosticNames(printDiagnosticNames) {}
 
   /// If the  message isn't available/localized in current context
   /// return the fallback default message.
@@ -186,9 +187,8 @@ class YAMLLocalizationProducer final : public LocalizationProducer {
 public:
   /// The diagnostics IDs that are no longer available in `.def`
   std::vector<std::string> unknownIDs;
-  explicit YAMLLocalizationProducer(
-      llvm::StringRef filePath,
-      bool printDiagnosticName = false);
+  explicit YAMLLocalizationProducer(llvm::StringRef filePath,
+                                    bool printDiagnosticNames = false);
 
   /// Iterate over all of the available (non-empty) translations
   /// maintained by this producer, callback gets each translation
@@ -210,7 +210,7 @@ class SerializedLocalizationProducer final : public LocalizationProducer {
 public:
   explicit SerializedLocalizationProducer(
       std::unique_ptr<llvm::MemoryBuffer> buffer,
-      bool printDiagnosticName = false);
+      bool printDiagnosticNames = false);
 
 protected:
   llvm::StringRef getMessage(swift::DiagID id) const override;

lib/AST/DiagnosticEngine.cpp

@@ -1113,8 +1113,8 @@ void DiagnosticEngine::emitDiagnostic(const Diagnostic &diagnostic) {
 
 llvm::StringRef
 DiagnosticEngine::diagnosticStringFor(const DiagID id,
-                                      bool printDiagnosticName) {
-  auto defaultMessage = printDiagnosticName
+                                      bool printDiagnosticNames) {
+  auto defaultMessage = printDiagnosticNames
                             ? debugDiagnosticStrings[(unsigned)id]
                             : diagnosticStrings[(unsigned)id];
   if (localization) {

lib/Localization/LocalizationFormat.cpp

@@ -97,8 +97,8 @@ LocalizationProducer::getMessageOr(swift::DiagID id,
   auto localizedMessage = getMessage(id);
   if (localizedMessage.empty())
     return defaultMessage;
-  llvm::StringRef diagnosticName(diagnosticNameStrings[(unsigned)id]);
-  if (printDiagnosticName) {
+  if (printDiagnosticNames) {
+    llvm::StringRef diagnosticName(diagnosticNameStrings[(unsigned)id]);
     auto localizedDebugDiagnosticMessage =
         localizationSaver.save(localizedMessage.str() + diagnosticName.str());
     return localizedDebugDiagnosticMessage;
@@ -107,8 +107,8 @@ LocalizationProducer::getMessageOr(swift::DiagID id,
 }
 
 SerializedLocalizationProducer::SerializedLocalizationProducer(
-    std::unique_ptr<llvm::MemoryBuffer> buffer, bool printDiagnosticName)
-    : LocalizationProducer(printDiagnosticName), Buffer(std::move(buffer)) {
+    std::unique_ptr<llvm::MemoryBuffer> buffer, bool printDiagnosticNames)
+    : LocalizationProducer(printDiagnosticNames), Buffer(std::move(buffer)) {
   auto base =
       reinterpret_cast<const unsigned char *>(Buffer.get()->getBufferStart());
   auto tableOffset = endian::read<offset_type>(base, little);
@@ -125,8 +125,8 @@ SerializedLocalizationProducer::getMessage(swift::DiagID id) const {
 }
 
 YAMLLocalizationProducer::YAMLLocalizationProducer(llvm::StringRef filePath,
-                                                   bool printDiagnosticName)
-    : LocalizationProducer(printDiagnosticName) {
+                                                   bool printDiagnosticNames)
+    : LocalizationProducer(printDiagnosticNames) {
   auto FileBufOrErr = llvm::MemoryBuffer::getFileOrSTDIN(filePath);
   llvm::MemoryBuffer *document = FileBufOrErr->get();
   diag::LocalizationInput yin(document->getBuffer());