diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
index 9c3c7cc70c18..225e867c9b24 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
@@ -474,10 +474,8 @@ void ProTypeMemberInitCheck::checkMissingMemberInitializer(
   // It only includes fields that have not been fixed
   SmallPtrSet<const FieldDecl *, 16> AllFieldsToInit;
   forEachField(ClassDecl, FieldsToInit, [&](const FieldDecl *F) {
-    if (!HasRecordClassMemberSet.contains(F)) {
+    if (HasRecordClassMemberSet.insert(F).second)
       AllFieldsToInit.insert(F);
-      HasRecordClassMemberSet.insert(F);
-    }
   });
   if (FieldsToInit.empty())
     return;