[clang-tidy] fix duplicate '{}' in cppcoreguidelines-pro-type-member-init

The overload of the constructor will repeatedly fix the member variables that need to be initialized.
Removed the duplicate '{}'.

```
struct A {
  A() {}
  A(int) {}
  int _var;  // int _var{}{};  <--  wrong fix
};
```

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D107641

clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp

@@ -433,17 +433,25 @@ void ProTypeMemberInitCheck::checkMissingMemberInitializer(
                [&](const FieldDecl *F) { OrderedFields.push_back(F); });
 
   // Collect all the fields we need to initialize, including indirect fields.
+  // It only includes fields that have not been fixed
   SmallPtrSet<const FieldDecl *, 16> AllFieldsToInit;
-  forEachField(ClassDecl, FieldsToInit,
-               [&](const FieldDecl *F) { AllFieldsToInit.insert(F); });
-  if (AllFieldsToInit.empty())
+  forEachField(ClassDecl, FieldsToInit, [&](const FieldDecl *F) {
+    if (!HasRecordClassMemberSet.contains(F)) {
+      AllFieldsToInit.insert(F);
+      HasRecordClassMemberSet.insert(F);
+    }
+  });
+  if (FieldsToInit.empty())
     return;
 
   DiagnosticBuilder Diag =
       diag(Ctor ? Ctor->getBeginLoc() : ClassDecl.getLocation(),
            "%select{|union }0constructor %select{does not|should}0 initialize "
            "%select{|one of }0these fields: %1")
-      << IsUnion << toCommaSeparatedString(OrderedFields, AllFieldsToInit);
+      << IsUnion << toCommaSeparatedString(OrderedFields, FieldsToInit);
+
+  if (AllFieldsToInit.empty())
+    return;
 
   // Do not propose fixes for constructors in macros since we cannot place them
   // correctly.

clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.h

@@ -10,6 +10,7 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_TYPE_MEMBER_INIT_H
 
 #include "../ClangTidyCheck.h"
+#include "llvm/ADT/DenseSet.h"
 
 namespace clang {
 namespace tidy {
@@ -72,6 +73,10 @@ private:
   // instead of brace initialization. Only effective in C++11 mode. Default is
   // false.
   bool UseAssignment;
+
+  // Record the member variables that have been initialized to prevent repeated
+  // initialization.
+  llvm::DenseSet<const FieldDecl *> HasRecordClassMemberSet;
 };
 
 } // namespace cppcoreguidelines

clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-pro-type-member-init.cpp

@@ -208,9 +208,8 @@ struct PositiveMultipleConstructors {
   PositiveMultipleConstructors(const PositiveMultipleConstructors &) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields: A, B
 
-  // FIXME: The fix-its here collide providing an erroneous fix
   int A, B;
-  // CHECK-FIXES: int A{}{}{}, B{}{}{};
+  // CHECK-FIXES: int A{}, B{};
 };
 
 typedef struct {