diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -6,12 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-//----------------understanding syntax of diagnostics messages--------===//
-//keyword after def represents symbolic constant for that diagnostics 
-//for %select{}num  The select operator uses num to select one of the alternatives inside the braces, which are separated by |. 
-//If you pass 0 as parameter , it will substitute the 0th alternative, which is the empty string; if you pass I, it will substitute the Ith alternative
-//%num is a placeholder for a parameter passed to the diagnostic engine where num can be 0 for first argument 1 for second argument and so on
-//===--------------------------------------------------------------------===//
 let Component = "AST" in {
 
 // Constant expression diagnostics. These (and their users) belong in Sema.
@@ -71,7 +65,7 @@
   "%select{pointer|reference}0 to a consteval declaration "
   "is not a constant expression">;
 def note_constexpr_uninitialized : Note<
-  "%select{|sub}0object of type %1 is not initialized">;
+  "%select{|sub}0object  %1 is not initialized">;
 def note_constexpr_static_local : Note<
   "control flows through the definition of a %select{static|thread_local}0 variable">;
 def note_constexpr_subobject_declared_here : Note<
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2119,7 +2119,7 @@
                                   EvalInfo &Info, SourceLocation DiagLoc,
                                   QualType Type, const APValue &Value,
                                   ConstantExprKind Kind,
-                                  SourceLocation SubobjectLoc,
+                                  const FieldDecl* SubobjectDecl,
                                   CheckedTemporaries &CheckedTemps);
 
 /// Check that this reference or pointer core constant expression is a valid
@@ -2267,7 +2267,7 @@
       assert(V && "evasluation result refers to uninitialised temporary");
       if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
                                  Info, MTE->getExprLoc(), TempType, *V,
-                                 Kind, SourceLocation(), CheckedTemps))
+                                 Kind,  /*SubobjectDecl=*/nullptr, CheckedTemps))
         return false;
     }
   }
@@ -2350,13 +2350,13 @@
                                   EvalInfo &Info, SourceLocation DiagLoc,
                                   QualType Type, const APValue &Value,
                                   ConstantExprKind Kind,
-                                  SourceLocation SubobjectLoc,
+                                  const FieldDecl* SubobjectDecl,
                                   CheckedTemporaries &CheckedTemps) {
-  if (!Value.hasValue()) {
+  if ((!Value.hasValue())&& SubobjectDecl!=nullptr) {
     Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
-      << true << Type;
-    if (SubobjectLoc.isValid())
-      Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here);
+      << true << SubobjectDecl->getName();
+    if (SubobjectDecl->getLocation().isValid())
+      Info.Note(SubobjectDecl->getLocation(), diag::note_constexpr_subobject_declared_here);
     return false;
   }
 
@@ -2372,20 +2372,20 @@
     QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
     for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
       if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
-                                 Value.getArrayInitializedElt(I), Kind,
-                                 SubobjectLoc, CheckedTemps))
+                                 Value.getArrayInitializedElt(I), Kind,SubobjectDecl
+                                 , CheckedTemps))
         return false;
     }
     if (!Value.hasArrayFiller())
       return true;
     return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
-                                 Value.getArrayFiller(), Kind, SubobjectLoc,
+                                 Value.getArrayFiller(), Kind, SubobjectDecl,
                                  CheckedTemps);
   }
   if (Value.isUnion() && Value.getUnionField()) {
     return CheckEvaluationResult(
         CERK, Info, DiagLoc, Value.getUnionField()->getType(),
-        Value.getUnionValue(), Kind, Value.getUnionField()->getLocation(),
+        Value.getUnionValue(), Kind, Value.getUnionField(),
         CheckedTemps);
   }
   if (Value.isStruct()) {
@@ -2395,7 +2395,7 @@
       for (const CXXBaseSpecifier &BS : CD->bases()) {
         if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
                                    Value.getStructBase(BaseIndex), Kind,
-                                   BS.getBeginLoc(), CheckedTemps))
+                                    /*SubobjectDecl=*/nullptr, CheckedTemps))
           return false;
         ++BaseIndex;
       }
@@ -2406,7 +2406,7 @@
 
       if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(),
                                  Value.getStructField(I->getFieldIndex()),
-                                 Kind, I->getLocation(), CheckedTemps))
+                                 Kind, I, CheckedTemps))
         return false;
     }
   }
@@ -2440,7 +2440,7 @@
   CheckedTemporaries CheckedTemps;
   return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
                                Info, DiagLoc, Type, Value, Kind,
-                               SourceLocation(), CheckedTemps);
+                               nullptr, CheckedTemps);
 }
 
 /// Check that this evaluated value is fully-initialized and can be loaded by
@@ -2450,7 +2450,7 @@
   CheckedTemporaries CheckedTemps;
   return CheckEvaluationResult(
       CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
-      ConstantExprKind::Normal, SourceLocation(), CheckedTemps);
+      ConstantExprKind::Normal,nullptr, CheckedTemps);
 }
 
 /// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
diff --git a/clang/lib/AST/Interp/Interp.cpp b/clang/lib/AST/Interp/Interp.cpp
--- a/clang/lib/AST/Interp/Interp.cpp
+++ b/clang/lib/AST/Interp/Interp.cpp
@@ -369,9 +369,9 @@
 }
 
 static void DiagnoseUninitializedSubobject(InterpState &S, const SourceInfo &SI,
-                                           QualType SubObjType,
+                                           StringRef SubObjName,
                                            SourceLocation SubObjLoc) {
-  S.FFDiag(SI, diag::note_constexpr_uninitialized) << true << SubObjType;
+  S.FFDiag(SI, diag::note_constexpr_uninitialized) << true << SubObjName;
   if (SubObjLoc.isValid())
     S.Note(SubObjLoc, diag::note_constexpr_subobject_declared_here);
 }
@@ -400,7 +400,7 @@
   } else {
     for (size_t I = 0; I != NumElems; ++I) {
       if (!BasePtr.atIndex(I).isInitialized()) {
-        DiagnoseUninitializedSubobject(S, S.Current->getSource(OpPC), ElemType,
+        DiagnoseUninitializedSubobject(S, S.Current->getSource(OpPC), BasePtr.getElemRecord()->getName(),
                                        BasePtr.getFieldDesc()->getLocation());
         Result = false;
       }
@@ -427,7 +427,7 @@
       Result &= CheckArrayInitialized(S, OpPC, FieldPtr, CAT);
     } else if (!FieldPtr.isInitialized()) {
       DiagnoseUninitializedSubobject(S, S.Current->getSource(OpPC),
-                                     F.Decl->getType(), F.Decl->getLocation());
+                                     F.Decl->getName(), F.Decl->getLocation());
       Result = false;
     }
   }