diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -472,7 +472,7 @@
     Buffer.append(CStr.first);
     StringRef Val = Options.get(Buffer, "");
     if (!Val.empty())
-      HNOption.CString[CStr.first] = Val.str();
+      HNOption.CString[CStr.second] = Val.str();
   }
 
   Buffer = {Section, "PrimitiveType."};