diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
index e8c1e3a610fa..83fc3727cb5c 100644
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -634,7 +634,7 @@ std::string IdentifierNamingCheck::HungarianNotation::getDataTypePrefix(
   return PrefixStr;
 }
 
-std::string IdentifierNamingCheck::HungarianNotation::getClassPrefix(
+llvm::StringRef IdentifierNamingCheck::HungarianNotation::getClassPrefix(
     const CXXRecordDecl *CRD,
     const IdentifierNamingCheck::HungarianNotationOption &HNOption) const {
   if (CRD->isUnion())
diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h
index 87735808dff3..b016556cc2ab 100644
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h
@@ -116,7 +116,7 @@ public:
         StringRef TypeName, const NamedDecl *ND,
         const IdentifierNamingCheck::HungarianNotationOption &HNOption) const;
 
-    std::string getClassPrefix(
+    llvm::StringRef getClassPrefix(
         const CXXRecordDecl *CRD,
         const IdentifierNamingCheck::HungarianNotationOption &HNOption) const;