diff --git a/clang/include/clang/AST/ASTConcept.h b/clang/include/clang/AST/ASTConcept.h
--- a/clang/include/clang/AST/ASTConcept.h
+++ b/clang/include/clang/AST/ASTConcept.h
@@ -14,7 +14,9 @@
 #ifndef LLVM_CLANG_AST_ASTCONCEPT_H
 #define LLVM_CLANG_AST_ASTCONCEPT_H
 
+#include "clang/AST/Decl.h"
 #include "clang/AST/Expr.h"
+#include "clang/AST/PrettyPrinter.h"
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/SmallVector.h"
@@ -107,9 +109,13 @@
   Rebuild(const ASTContext &C, const ASTConstraintSatisfaction &Satisfaction);
 };
 
+/*
+NOTE(massberg): This will be our new AST node.
+It is a reference to a conecpt and it template arguments.
+*/
 /// \brief Common data class for constructs that reference concepts with
 /// template arguments.
-class ConceptReference {
+class ConceptLoc {
 protected:
   // \brief The optional nested name specifier used when naming the concept.
   NestedNameSpecifierLoc NestedNameSpec;
@@ -135,17 +141,26 @@
   const ASTTemplateArgumentListInfo *ArgsAsWritten;
 
 public:
-  ConceptReference(NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
-                   DeclarationNameInfo ConceptNameInfo, NamedDecl *FoundDecl,
-                   ConceptDecl *NamedConcept,
-                   const ASTTemplateArgumentListInfo *ArgsAsWritten)
+  ConceptLoc(NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
+             DeclarationNameInfo ConceptNameInfo, NamedDecl *FoundDecl,
+             ConceptDecl *NamedConcept,
+             const ASTTemplateArgumentListInfo *ArgsAsWritten)
       : NestedNameSpec(NNS), TemplateKWLoc(TemplateKWLoc),
         ConceptName(ConceptNameInfo), FoundDecl(FoundDecl),
         NamedConcept(NamedConcept), ArgsAsWritten(ArgsAsWritten) {}
 
-  ConceptReference()
+  ConceptLoc()
       : FoundDecl(nullptr), NamedConcept(nullptr), ArgsAsWritten(nullptr) {}
 
+  static ConceptLoc *Create(const ASTContext &C, NestedNameSpecifierLoc NNS,
+                            SourceLocation TemplateKWLoc,
+                            DeclarationNameInfo ConceptNameInfo,
+                            NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
+                            const ASTTemplateArgumentListInfo *ArgsAsWritten) {
+    return new (C) ConceptLoc(NNS, TemplateKWLoc, ConceptNameInfo, FoundDecl,
+                              NamedConcept, ArgsAsWritten);
+  }
+
   const NestedNameSpecifierLoc &getNestedNameSpecifierLoc() const {
     return NestedNameSpec;
   }
@@ -175,22 +190,27 @@
   bool hasExplicitTemplateArgs() const {
     return ArgsAsWritten != nullptr;
   }
+
+  void print(llvm::raw_ostream &OS, PrintingPolicy Policy) const;
 };
 
-class TypeConstraint : public ConceptReference {
+/*
+NOTE(massberg):
+A concept reference that uses abbreviated syntax to constrains a template
+type parameter:
+   template <convertible_to<string> T> void print(T object);
+
+*/
+class TypeConstraint {
   /// \brief The immediately-declared constraint expression introduced by this
   /// type-constraint.
   Expr *ImmediatelyDeclaredConstraint = nullptr;
+  ConceptLoc *Loc;
 
 public:
-  TypeConstraint(NestedNameSpecifierLoc NNS,
-                 DeclarationNameInfo ConceptNameInfo, NamedDecl *FoundDecl,
-                 ConceptDecl *NamedConcept,
-                 const ASTTemplateArgumentListInfo *ArgsAsWritten,
-                 Expr *ImmediatelyDeclaredConstraint) :
-      ConceptReference(NNS, /*TemplateKWLoc=*/SourceLocation(), ConceptNameInfo,
-                       FoundDecl, NamedConcept, ArgsAsWritten),
-      ImmediatelyDeclaredConstraint(ImmediatelyDeclaredConstraint) {}
+  TypeConstraint(ConceptLoc *Loc, Expr *ImmediatelyDeclaredConstraint)
+      : ImmediatelyDeclaredConstraint(ImmediatelyDeclaredConstraint), Loc(Loc) {
+  }
 
   /// \brief Get the immediately-declared constraint expression introduced by
   /// this type-constraint, that is - the constraint expression that is added to
@@ -199,7 +219,38 @@
     return ImmediatelyDeclaredConstraint;
   }
 
-  void print(llvm::raw_ostream &OS, PrintingPolicy Policy) const;
+  ConceptLoc *getConceptLoc() const { return Loc; }
+
+  // NOTE(massberg): For the first minimal prototype we keep the
+  // following functions to prevent. Later these functions should
+  // be accessed getConceptLoc().
+  ConceptDecl *getNamedConcept() const { return Loc->getNamedConcept(); }
+
+  SourceLocation getConceptNameLoc() const { return Loc->getConceptNameLoc(); }
+
+  bool hasExplicitTemplateArgs() const {
+    return Loc->hasExplicitTemplateArgs();
+  }
+
+  const ASTTemplateArgumentListInfo *getTemplateArgsAsWritten() const {
+    return Loc->getTemplateArgsAsWritten();
+  }
+
+  SourceLocation getTemplateKWLoc() const { return Loc->getTemplateKWLoc(); }
+
+  NamedDecl *getFoundDecl() const { return Loc->getFoundDecl(); }
+
+  const NestedNameSpecifierLoc &getNestedNameSpecifierLoc() const {
+    return Loc->getNestedNameSpecifierLoc();
+  }
+
+  const DeclarationNameInfo &getConceptNameInfo() const {
+    return Loc->getConceptNameInfo();
+  }
+
+  void print(llvm::raw_ostream &OS, PrintingPolicy Policy) const {
+    Loc->print(OS, Policy);
+  }
 };
 
 } // clang
diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -1373,11 +1373,7 @@
          nullptr;
   }
 
-  void setTypeConstraint(NestedNameSpecifierLoc NNS,
-                         DeclarationNameInfo NameInfo, NamedDecl *FoundDecl,
-                         ConceptDecl *CD,
-                         const ASTTemplateArgumentListInfo *ArgsAsWritten,
-                         Expr *ImmediatelyDeclaredConstraint);
+  void setTypeConstraint(ConceptLoc *Loc, Expr *ImmediatelyDeclaredConstraint);
 
   /// Determine whether this template parameter has a type-constraint.
   bool hasTypeConstraint() const {
diff --git a/clang/include/clang/AST/ExprConcepts.h b/clang/include/clang/AST/ExprConcepts.h
--- a/clang/include/clang/AST/ExprConcepts.h
+++ b/clang/include/clang/AST/ExprConcepts.h
@@ -38,7 +38,7 @@
 ///
 /// According to C++2a [expr.prim.id]p3 an id-expression that denotes the
 /// specialization of a concept results in a prvalue of type bool.
-class ConceptSpecializationExpr final : public Expr, public ConceptReference {
+class ConceptSpecializationExpr final : public Expr {
   friend class ASTReader;
   friend class ASTStmtReader;
 
@@ -46,6 +46,8 @@
   using SubstitutionDiagnostic = std::pair<SourceLocation, std::string>;
 
 protected:
+  ConceptLoc *Loc;
+
   /// \brief The Implicit Concept Specialization Decl, which holds the template
   /// arguments for this specialization.
   ImplicitConceptSpecializationDecl *SpecDecl;
@@ -55,16 +57,11 @@
   /// ignored.
   ASTConstraintSatisfaction *Satisfaction;
 
-  ConceptSpecializationExpr(const ASTContext &C, NestedNameSpecifierLoc NNS,
-                            SourceLocation TemplateKWLoc,
-                            DeclarationNameInfo ConceptNameInfo,
-                            NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
-                            const ASTTemplateArgumentListInfo *ArgsAsWritten,
+  ConceptSpecializationExpr(const ASTContext &C, ConceptLoc *Loc,
                             ImplicitConceptSpecializationDecl *SpecDecl,
                             const ConstraintSatisfaction *Satisfaction);
 
-  ConceptSpecializationExpr(const ASTContext &C, ConceptDecl *NamedConcept,
-                            const ASTTemplateArgumentListInfo *ArgsAsWritten,
+  ConceptSpecializationExpr(const ASTContext &C, ConceptLoc *Loc,
                             ImplicitConceptSpecializationDecl *SpecDecl,
                             const ConstraintSatisfaction *Satisfaction,
                             bool Dependent,
@@ -73,16 +70,12 @@
 
 public:
   static ConceptSpecializationExpr *
-  Create(const ASTContext &C, NestedNameSpecifierLoc NNS,
-         SourceLocation TemplateKWLoc, DeclarationNameInfo ConceptNameInfo,
-         NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
-         const ASTTemplateArgumentListInfo *ArgsAsWritten,
+  Create(const ASTContext &C, ConceptLoc *Loc,
          ImplicitConceptSpecializationDecl *SpecDecl,
          const ConstraintSatisfaction *Satisfaction);
 
   static ConceptSpecializationExpr *
-  Create(const ASTContext &C, ConceptDecl *NamedConcept,
-         const ASTTemplateArgumentListInfo *ArgsAsWritten,
+  Create(const ASTContext &C, ConceptLoc *Loc,
          ImplicitConceptSpecializationDecl *SpecDecl,
          const ConstraintSatisfaction *Satisfaction, bool Dependent,
          bool ContainsUnexpandedParameterPack);
@@ -91,6 +84,34 @@
     return SpecDecl->getTemplateArguments();
   }
 
+  const ConceptLoc *getConceptLoc() const { return Loc; }
+
+  // NOTE(massberg): For the first minimal prototype we keep the
+  // following functions to prevent. Later these functions should
+  // be accessed getConceptLoc().
+  ConceptDecl *getNamedConcept() const { return Loc->getNamedConcept(); }
+
+  bool hasExplicitTemplateArgs() const {
+    return Loc->hasExplicitTemplateArgs();
+  }
+
+  SourceLocation getConceptNameLoc() const { return Loc->getConceptNameLoc(); }
+  const ASTTemplateArgumentListInfo *getTemplateArgsAsWritten() const {
+    return Loc->getTemplateArgsAsWritten();
+  }
+
+  const NestedNameSpecifierLoc &getNestedNameSpecifierLoc() const {
+    return Loc->getNestedNameSpecifierLoc();
+  }
+
+  SourceLocation getTemplateKWLoc() const { return Loc->getTemplateKWLoc(); }
+
+  NamedDecl *getFoundDecl() const { return Loc->getFoundDecl(); }
+
+  const DeclarationNameInfo &getConceptNameInfo() const {
+    return Loc->getConceptNameInfo();
+  }
+
   const ImplicitConceptSpecializationDecl *getSpecializationDecl() const {
     assert(SpecDecl && "Template Argument Decl not initialized");
     return SpecDecl;
@@ -119,17 +140,19 @@
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
-    if (auto QualifierLoc = getNestedNameSpecifierLoc())
+    if (auto QualifierLoc = Loc->getNestedNameSpecifierLoc())
       return QualifierLoc.getBeginLoc();
-    return ConceptName.getBeginLoc();
+    return Loc->getConceptNameInfo().getBeginLoc();
   }
 
   SourceLocation getEndLoc() const LLVM_READONLY {
     // If the ConceptSpecializationExpr is the ImmediatelyDeclaredConstraint
     // of a TypeConstraint written syntactically as a constrained-parameter,
     // there may not be a template argument list.
-    return ArgsAsWritten->RAngleLoc.isValid() ? ArgsAsWritten->RAngleLoc
-                                              : ConceptName.getEndLoc();
+    return Loc->hasExplicitTemplateArgs() &&
+                   Loc->getTemplateArgsAsWritten()->getRAngleLoc().isValid()
+               ? Loc->getTemplateArgsAsWritten()->getRAngleLoc()
+               : Loc->getConceptNameInfo().getEndLoc();
   }
 
   // Iterators
diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -312,6 +312,10 @@
   /// \returns false if the visitation was terminated early, true otherwise.
   bool TraverseObjCProtocolLoc(ObjCProtocolLoc ProtocolLoc);
 
+  /// Recursively visit concept reference with location information.
+  ///
+  /// \returns false if the visitation was terminated early, true otherwise.
+  bool TraverseConceptLoc(const ConceptLoc *CL);
   // ---- Methods on Attrs ----
 
   // Visit an attribute.
@@ -469,9 +473,6 @@
 private:
   // These are helper methods used by more than one Traverse* method.
   bool TraverseTemplateParameterListHelper(TemplateParameterList *TPL);
-  /// Traverses the qualifier, name and template arguments of a concept
-  /// reference.
-  bool TraverseConceptReferenceHelper(const ConceptReference &C);
 
   // Traverses template parameter lists of either a DeclaratorDecl or TagDecl.
   template <typename T>
@@ -507,17 +508,17 @@
 bool RecursiveASTVisitor<Derived>::TraverseTypeConstraint(
     const TypeConstraint *C) {
   if (!getDerived().shouldVisitImplicitCode()) {
-    TRY_TO(TraverseConceptReferenceHelper(*C));
+    TRY_TO(TraverseConceptLoc(C->getConceptLoc()));
     return true;
   }
   if (Expr *IDC = C->getImmediatelyDeclaredConstraint()) {
     TRY_TO(TraverseStmt(IDC));
   } else {
-    // Avoid traversing the ConceptReference in the TypeConstraint
+    // Avoid traversing the ConceptLoc in the TypeConstraint
     // if we have an immediately-declared-constraint, otherwise
     // we'll end up visiting the concept and the arguments in
     // the TC twice.
-    TRY_TO(TraverseConceptReferenceHelper(*C));
+    TRY_TO(TraverseConceptLoc(C->getConceptLoc()));
   }
   return true;
 }
@@ -540,18 +541,6 @@
   llvm_unreachable("unexpected case");
 }
 
-template <typename Derived>
-bool RecursiveASTVisitor<Derived>::TraverseConceptReferenceHelper(
-    const ConceptReference &C) {
-  TRY_TO(TraverseNestedNameSpecifierLoc(C.getNestedNameSpecifierLoc()));
-  TRY_TO(TraverseDeclarationNameInfo(C.getConceptNameInfo()));
-  if (C.hasExplicitTemplateArgs())
-    TRY_TO(TraverseTemplateArgumentLocsHelper(
-        C.getTemplateArgsAsWritten()->getTemplateArgs(),
-        C.getTemplateArgsAsWritten()->NumTemplateArgs));
-  return true;
-}
-
 template <typename Derived>
 bool RecursiveASTVisitor<Derived>::dataTraverseNode(Stmt *S,
                                                     DataRecursionQueue *Queue) {
@@ -1356,10 +1345,7 @@
 DEF_TRAVERSE_TYPELOC(AutoType, {
   TRY_TO(TraverseType(TL.getTypePtr()->getDeducedType()));
   if (TL.isConstrained()) {
-    TRY_TO(TraverseNestedNameSpecifierLoc(TL.getNestedNameSpecifierLoc()));
-    TRY_TO(TraverseDeclarationNameInfo(TL.getConceptNameInfo()));
-    for (unsigned I = 0, E = TL.getNumArgs(); I != E; ++I)
-      TRY_TO(TraverseTemplateArgumentLoc(TL.getArgLoc(I)));
+    TRY_TO(TraverseConceptLoc(TL.getConceptLoc()));
   }
 })
 
@@ -2522,6 +2508,17 @@
   return true;
 }
 
+template <typename Derived>
+bool RecursiveASTVisitor<Derived>::TraverseConceptLoc(const ConceptLoc *CL) {
+  TRY_TO(TraverseNestedNameSpecifierLoc(CL->getNestedNameSpecifierLoc()));
+  TRY_TO(TraverseDeclarationNameInfo(CL->getConceptNameInfo()));
+  if (CL->hasExplicitTemplateArgs())
+    TRY_TO(TraverseTemplateArgumentLocsHelper(
+        CL->getTemplateArgsAsWritten()->getTemplateArgs(),
+        CL->getTemplateArgsAsWritten()->NumTemplateArgs));
+  return true;
+}
+
 // If shouldVisitImplicitCode() returns false, this method traverses only the
 // syntactic form of InitListExpr.
 // If shouldVisitImplicitCode() return true, this method is called once for
@@ -2900,7 +2897,7 @@
 })
 
 DEF_TRAVERSE_STMT(ConceptSpecializationExpr,
-                  { TRY_TO(TraverseConceptReferenceHelper(*S)); })
+                  { TRY_TO(TraverseConceptLoc(S->getConceptLoc())); })
 
 DEF_TRAVERSE_STMT(RequiresExpr, {
   TRY_TO(TraverseDecl(S->getBody()));
diff --git a/clang/include/clang/AST/TypeLoc.h b/clang/include/clang/AST/TypeLoc.h
--- a/clang/include/clang/AST/TypeLoc.h
+++ b/clang/include/clang/AST/TypeLoc.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_CLANG_AST_TYPELOC_H
 #define LLVM_CLANG_AST_TYPELOC_H
 
+#include "clang/AST/ASTConcept.h"
 #include "clang/AST/DeclarationName.h"
 #include "clang/AST/NestedNameSpecifier.h"
 #include "clang/AST/TemplateBase.h"
@@ -2104,16 +2105,14 @@
                                        DeducedType> {};
 
 struct AutoTypeLocInfo : TypeSpecLocInfo {
-  NestedNameSpecifierLoc NestedNameSpec;
-  SourceLocation TemplateKWLoc;
-  SourceLocation ConceptNameLoc;
-  NamedDecl *FoundDecl = nullptr;
   SourceLocation LAngleLoc;
   SourceLocation RAngleLoc;
 
   // For decltype(auto).
   SourceLocation RParenLoc;
 
+  SourceLocation DefaultLoc;
+  ConceptLoc *CL = nullptr;
   // Followed by a TemplateArgumentLocInfo[]
 };
 
@@ -2135,43 +2134,51 @@
     return getTypePtr()->isConstrained();
   }
 
-  const NestedNameSpecifierLoc &getNestedNameSpecifierLoc() const {
-    return getLocalData()->NestedNameSpec;
+  void setConceptLoc(ConceptLoc *Loc) {
+    getLocalData()->CL = Loc;
+    if (Loc == nullptr)
+      return;
   }
 
-  void setNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS) {
-    getLocalData()->NestedNameSpec = NNS;
-  }
+  ConceptLoc *getConceptLoc() const { return getLocalData()->CL; }
 
-  SourceLocation getTemplateKWLoc() const {
-    return getLocalData()->TemplateKWLoc;
-  }
+  void setDefaultLoc(SourceLocation Loc) { getLocalData()->DefaultLoc = Loc; }
 
-  void setTemplateKWLoc(SourceLocation Loc) {
-    getLocalData()->TemplateKWLoc = Loc;
-  }
+  SourceLocation getDefaultLoc() const { return getLocalData()->DefaultLoc; }
 
-  SourceLocation getConceptNameLoc() const {
-    return getLocalData()->ConceptNameLoc;
+  const NestedNameSpecifierLoc getNestedNameSpecifierLoc() const {
+    if (getConceptLoc())
+      return getConceptLoc()->getNestedNameSpecifierLoc();
+    return NestedNameSpecifierLoc();
   }
 
-  void setConceptNameLoc(SourceLocation Loc) {
-    getLocalData()->ConceptNameLoc = Loc;
+  SourceLocation getTemplateKWLoc() const {
+    if (getConceptLoc())
+      return getConceptLoc()->getTemplateKWLoc();
+    return getDefaultLoc();
   }
 
-  NamedDecl *getFoundDecl() const {
-    return getLocalData()->FoundDecl;
+  SourceLocation getConceptNameLoc() const {
+    if (getConceptLoc())
+      return getConceptLoc()->getConceptNameLoc();
+    return getDefaultLoc();
   }
 
-  void setFoundDecl(NamedDecl *D) {
-    getLocalData()->FoundDecl = D;
+  NamedDecl *getFoundDecl() const {
+    if (getConceptLoc())
+      return getConceptLoc()->getFoundDecl();
+    return nullptr;
   }
 
   ConceptDecl *getNamedConcept() const {
-    return getTypePtr()->getTypeConstraintConcept();
+    if (getConceptLoc())
+      return getConceptLoc()->getNamedConcept();
+    return nullptr;
   }
 
-  DeclarationNameInfo getConceptNameInfo() const;
+  DeclarationNameInfo getConceptNameInfo() const {
+    return getConceptLoc()->getConceptNameInfo();
+  }
 
   bool hasExplicitTemplateArgs() const {
     return getLocalData()->LAngleLoc.isValid();
@@ -2197,17 +2204,13 @@
     return getTypePtr()->getTypeConstraintArguments().size();
   }
 
-  void setArgLocInfo(unsigned i, TemplateArgumentLocInfo AI) {
-    getArgInfos()[i] = AI;
-  }
-
-  TemplateArgumentLocInfo getArgLocInfo(unsigned i) const {
-    return getArgInfos()[i];
-  }
-
   TemplateArgumentLoc getArgLoc(unsigned i) const {
+    if (getConceptLoc())
+      return getConceptLoc()->getTemplateArgsAsWritten()->getTemplateArgs()[i];
+    // FIXME: Check why we still need this fallback in case that there is no
+    // ConceptLoc.
     return TemplateArgumentLoc(getTypePtr()->getTypeConstraintArguments()[i],
-                               getArgLocInfo(i));
+                               getArgInfos()[i]);
   }
 
   SourceRange getLocalSourceRange() const {
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -6345,11 +6345,12 @@
   auto *NCY = YTC->getNamedConcept();
   if (!NCX || !NCY || !isSameEntity(NCX, NCY))
     return false;
-  if (XTC->hasExplicitTemplateArgs() != YTC->hasExplicitTemplateArgs())
+  if (XTC->getConceptLoc()->hasExplicitTemplateArgs() !=
+      YTC->getConceptLoc()->hasExplicitTemplateArgs())
     return false;
-  if (XTC->hasExplicitTemplateArgs())
-    if (XTC->getTemplateArgsAsWritten()->NumTemplateArgs !=
-        YTC->getTemplateArgsAsWritten()->NumTemplateArgs)
+  if (XTC->getConceptLoc()->hasExplicitTemplateArgs())
+    if (XTC->getConceptLoc()->getTemplateArgsAsWritten()->NumTemplateArgs !=
+        YTC->getConceptLoc()->getTemplateArgsAsWritten()->NumTemplateArgs)
       return false;
 
   // Compare slowly by profiling.
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -5652,13 +5652,14 @@
       if (Error Err = ImportTemplateArgumentListInfo(*ASTTemplateArgs,
                                                      ToTAInfo))
         return std::move(Err);
-
-    ToD->setTypeConstraint(ToNNS, DeclarationNameInfo(ToName, ToNameLoc),
-        ToFoundDecl, ToNamedConcept,
-        ASTTemplateArgs ?
-            ASTTemplateArgumentListInfo::Create(Importer.getToContext(),
-                                                ToTAInfo) : nullptr,
-        ToIDC);
+    auto *CL = ConceptLoc::Create(
+        Importer.getToContext(), ToNNS,
+        ToNameLoc, // What is the right Loc here?
+        DeclarationNameInfo(ToName, ToNameLoc), ToFoundDecl, ToNamedConcept,
+        ASTTemplateArgs ? ASTTemplateArgumentListInfo::Create(
+                              Importer.getToContext(), ToTAInfo)
+                        : nullptr);
+    ToD->setTypeConstraint(CL, ToIDC);
   }
 
   if (D->hasDefaultArgument()) {
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -697,17 +697,15 @@
   return getTypeForDecl()->castAs<TemplateTypeParmType>()->isParameterPack();
 }
 
-void TemplateTypeParmDecl::setTypeConstraint(NestedNameSpecifierLoc NNS,
-    DeclarationNameInfo NameInfo, NamedDecl *FoundDecl, ConceptDecl *CD,
-    const ASTTemplateArgumentListInfo *ArgsAsWritten,
-    Expr *ImmediatelyDeclaredConstraint) {
+void TemplateTypeParmDecl::setTypeConstraint(
+    ConceptLoc *Loc, Expr *ImmediatelyDeclaredConstraint) {
   assert(HasTypeConstraint &&
          "HasTypeConstraint=true must be passed at construction in order to "
          "call setTypeConstraint");
   assert(!TypeConstraintInitialized &&
          "TypeConstraint was already initialized!");
-  new (getTrailingObjects<TypeConstraint>()) TypeConstraint(NNS, NameInfo,
-      FoundDecl, CD, ArgsAsWritten, ImmediatelyDeclaredConstraint);
+  new (getTrailingObjects<TypeConstraint>())
+      TypeConstraint(Loc, ImmediatelyDeclaredConstraint);
   TypeConstraintInitialized = true;
 }
 
@@ -1554,7 +1552,7 @@
                    createBuiltinTemplateParameterList(C, DC, BTK)),
       BTK(BTK) {}
 
-void TypeConstraint::print(llvm::raw_ostream &OS, PrintingPolicy Policy) const {
+void ConceptLoc::print(llvm::raw_ostream &OS, PrintingPolicy Policy) const {
   if (NestedNameSpec)
     NestedNameSpec.getNestedNameSpecifier()->print(OS, Policy);
   ConceptName.printName(OS, Policy);
diff --git a/clang/lib/AST/ExprConcepts.cpp b/clang/lib/AST/ExprConcepts.cpp
--- a/clang/lib/AST/ExprConcepts.cpp
+++ b/clang/lib/AST/ExprConcepts.cpp
@@ -31,26 +31,24 @@
 using namespace clang;
 
 ConceptSpecializationExpr::ConceptSpecializationExpr(
-    const ASTContext &C, NestedNameSpecifierLoc NNS,
-    SourceLocation TemplateKWLoc, DeclarationNameInfo ConceptNameInfo,
-    NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
-    const ASTTemplateArgumentListInfo *ArgsAsWritten,
+    const ASTContext &C, ConceptLoc *Loc,
     ImplicitConceptSpecializationDecl *SpecDecl,
     const ConstraintSatisfaction *Satisfaction)
     : Expr(ConceptSpecializationExprClass, C.BoolTy, VK_PRValue, OK_Ordinary),
-      ConceptReference(NNS, TemplateKWLoc, ConceptNameInfo, FoundDecl,
-                       NamedConcept, ArgsAsWritten),
-      SpecDecl(SpecDecl),
+      Loc(Loc), SpecDecl(SpecDecl),
       Satisfaction(Satisfaction
                        ? ASTConstraintSatisfaction::Create(C, *Satisfaction)
                        : nullptr) {
   setDependence(computeDependence(this, /*ValueDependent=*/!Satisfaction));
 
   // Currently guaranteed by the fact concepts can only be at namespace-scope.
-  assert(!NestedNameSpec ||
-         (!NestedNameSpec.getNestedNameSpecifier()->isInstantiationDependent() &&
-          !NestedNameSpec.getNestedNameSpecifier()
-              ->containsUnexpandedParameterPack()));
+  assert(!Loc->getNestedNameSpecifierLoc() ||
+         (!Loc->getNestedNameSpecifierLoc()
+               .getNestedNameSpecifier()
+               ->isInstantiationDependent() &&
+          !Loc->getNestedNameSpecifierLoc()
+               .getNestedNameSpecifier()
+               ->containsUnexpandedParameterPack()));
   assert((!isValueDependent() || isInstantiationDependent()) &&
          "should not be value-dependent");
 }
@@ -58,29 +56,20 @@
 ConceptSpecializationExpr::ConceptSpecializationExpr(EmptyShell Empty)
     : Expr(ConceptSpecializationExprClass, Empty) {}
 
-ConceptSpecializationExpr *ConceptSpecializationExpr::Create(
-    const ASTContext &C, NestedNameSpecifierLoc NNS,
-    SourceLocation TemplateKWLoc, DeclarationNameInfo ConceptNameInfo,
-    NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
-    const ASTTemplateArgumentListInfo *ArgsAsWritten,
-    ImplicitConceptSpecializationDecl *SpecDecl,
-    const ConstraintSatisfaction *Satisfaction) {
-  return new (C) ConceptSpecializationExpr(
-      C, NNS, TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
-      ArgsAsWritten, SpecDecl, Satisfaction);
+ConceptSpecializationExpr *
+ConceptSpecializationExpr::Create(const ASTContext &C, ConceptLoc *Loc,
+                                  ImplicitConceptSpecializationDecl *SpecDecl,
+                                  const ConstraintSatisfaction *Satisfaction) {
+  return new (C) ConceptSpecializationExpr(C, Loc, SpecDecl, Satisfaction);
 }
 
 ConceptSpecializationExpr::ConceptSpecializationExpr(
-    const ASTContext &C, ConceptDecl *NamedConcept,
-    const ASTTemplateArgumentListInfo *ArgsAsWritten,
+    const ASTContext &C, ConceptLoc *Loc,
     ImplicitConceptSpecializationDecl *SpecDecl,
     const ConstraintSatisfaction *Satisfaction, bool Dependent,
     bool ContainsUnexpandedParameterPack)
     : Expr(ConceptSpecializationExprClass, C.BoolTy, VK_PRValue, OK_Ordinary),
-      ConceptReference(NestedNameSpecifierLoc(), SourceLocation(),
-                       DeclarationNameInfo(), NamedConcept, NamedConcept,
-                       ArgsAsWritten),
-      SpecDecl(SpecDecl),
+      Loc(Loc), SpecDecl(SpecDecl),
       Satisfaction(Satisfaction
                        ? ASTConstraintSatisfaction::Create(C, *Satisfaction)
                        : nullptr) {
@@ -94,15 +83,15 @@
   setDependence(D);
 }
 
-ConceptSpecializationExpr *ConceptSpecializationExpr::Create(
-    const ASTContext &C, ConceptDecl *NamedConcept,
-    const ASTTemplateArgumentListInfo *ArgsAsWritten,
-    ImplicitConceptSpecializationDecl *SpecDecl,
-    const ConstraintSatisfaction *Satisfaction, bool Dependent,
-    bool ContainsUnexpandedParameterPack) {
-  return new (C) ConceptSpecializationExpr(C, NamedConcept, ArgsAsWritten,
-                                           SpecDecl, Satisfaction, Dependent,
-                                           ContainsUnexpandedParameterPack);
+ConceptSpecializationExpr *
+ConceptSpecializationExpr::Create(const ASTContext &C, ConceptLoc *Loc,
+                                  ImplicitConceptSpecializationDecl *SpecDecl,
+                                  const ConstraintSatisfaction *Satisfaction,
+                                  bool Dependent,
+                                  bool ContainsUnexpandedParameterPack) {
+  return new (C)
+      ConceptSpecializationExpr(C, Loc, SpecDecl, Satisfaction, Dependent,
+                                ContainsUnexpandedParameterPack);
 }
 
 const TypeConstraint *
diff --git a/clang/lib/AST/TypeLoc.cpp b/clang/lib/AST/TypeLoc.cpp
--- a/clang/lib/AST/TypeLoc.cpp
+++ b/clang/lib/AST/TypeLoc.cpp
@@ -621,25 +621,17 @@
   }
 }
 
-DeclarationNameInfo AutoTypeLoc::getConceptNameInfo() const {
-  return DeclarationNameInfo(getNamedConcept()->getDeclName(),
-                             getLocalData()->ConceptNameLoc);
-}
-
 void AutoTypeLoc::initializeLocal(ASTContext &Context, SourceLocation Loc) {
-  setNestedNameSpecifierLoc(NestedNameSpecifierLoc());
-  setTemplateKWLoc(Loc);
-  setConceptNameLoc(Loc);
-  setFoundDecl(nullptr);
   setRAngleLoc(Loc);
   setLAngleLoc(Loc);
   setRParenLoc(Loc);
   TemplateSpecializationTypeLoc::initializeArgLocs(
       Context, getTypePtr()->getTypeConstraintArguments(), getArgInfos(), Loc);
   setNameLoc(Loc);
+  setConceptLoc(nullptr);
+  setDefaultLoc(Loc);
 }
 
-
 namespace {
 
   class GetContainedAutoTypeLocVisitor :
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -23,6 +23,7 @@
 #include "clang/Basic/DiagnosticSema.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/PartialDiagnostic.h"
+#include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Stack.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Sema/DeclSpec.h"
@@ -1256,9 +1257,13 @@
   if (ImmediatelyDeclaredConstraint.isInvalid())
     return true;
 
-  ConstrainedParameter->setTypeConstraint(NS, NameInfo,
-                                          /*FoundDecl=*/NamedConcept,
-                                          NamedConcept, ArgsAsWritten,
+  auto *CL = ConceptLoc::Create(Context, /*NNS=*/NS,
+                                /*TemplateKWLoc=*/SourceLocation{},
+                                /*ConceptNameInfo=*/NameInfo,
+                                /*FoundDecl=*/NamedConcept,
+                                /*NamedConcept=*/NamedConcept,
+                                /*ArgsWritten=*/ArgsAsWritten);
+  ConstrainedParameter->setTypeConstraint(CL,
                                           ImmediatelyDeclaredConstraint.get());
   return false;
 }
@@ -4941,13 +4946,13 @@
                       TemplateArgs->getRAngleLoc()),
           Satisfaction))
     return ExprError();
-
-  return ConceptSpecializationExpr::Create(
+  auto *CL = ConceptLoc::Create(
       Context,
       SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
       TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
-      ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), CSD,
-      AreArgsDependent ? nullptr : &Satisfaction);
+      ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs));
+  return ConceptSpecializationExpr::Create(
+      Context, CL, CSD, AreArgsDependent ? nullptr : &Satisfaction);
 }
 
 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -2764,11 +2764,9 @@
       TC->getTemplateArgsAsWritten();
 
   if (!EvaluateConstraints) {
-    Inst->setTypeConstraint(TC->getNestedNameSpecifierLoc(),
-                            TC->getConceptNameInfo(), TC->getNamedConcept(),
-                            TC->getNamedConcept(), TemplArgInfo,
-                            TC->getImmediatelyDeclaredConstraint());
-    return false;
+      Inst->setTypeConstraint(TC->getConceptLoc(),
+                              TC->getImmediatelyDeclaredConstraint());
+      return false;
   }
 
   TemplateArgumentListInfo InstArgs;
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -6300,24 +6300,33 @@
       TemplateIdAnnotation *TemplateId = DS.getRepAsTemplateId();
       if (!TemplateId)
         return;
-      if (DS.getTypeSpecScope().isNotEmpty())
-        TL.setNestedNameSpecifierLoc(
-            DS.getTypeSpecScope().getWithLocInContext(Context));
-      else
-        TL.setNestedNameSpecifierLoc(NestedNameSpecifierLoc());
-      TL.setTemplateKWLoc(TemplateId->TemplateKWLoc);
-      TL.setConceptNameLoc(TemplateId->TemplateNameLoc);
-      TL.setFoundDecl(nullptr);
+
+      NestedNameSpecifierLoc NNS =
+          (DS.getTypeSpecScope().isNotEmpty()
+               ? DS.getTypeSpecScope().getWithLocInContext(Context)
+               : NestedNameSpecifierLoc());
       TL.setLAngleLoc(TemplateId->LAngleLoc);
       TL.setRAngleLoc(TemplateId->RAngleLoc);
-      if (TemplateId->NumArgs == 0)
-        return;
       TemplateArgumentListInfo TemplateArgsInfo;
-      ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
-                                         TemplateId->NumArgs);
-      SemaRef.translateTemplateArguments(TemplateArgsPtr, TemplateArgsInfo);
-      for (unsigned I = 0; I < TemplateId->NumArgs; ++I)
-        TL.setArgLocInfo(I, TemplateArgsInfo.arguments()[I].getLocInfo());
+      if (TemplateId->NumArgs > 0) {
+        ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
+                                           TemplateId->NumArgs);
+        SemaRef.translateTemplateArguments(TemplateArgsPtr, TemplateArgsInfo);
+        /*for (unsigned I = 0; I < TemplateId->NumArgs; ++I)
+          TL.setArgLocInfo(I, TemplateArgsInfo.arguments()[I].getLocInfo());*/
+      }
+      // FIXME: Move to VisitConceptLoc,
+      DeclarationNameInfo DNI = DeclarationNameInfo(
+          TL.getTypePtr()->getTypeConstraintConcept()->getDeclName(),
+          TemplateId->TemplateNameLoc);
+      auto *CL = ConceptLoc::Create(
+          Context, NNS, TemplateId->TemplateKWLoc, DNI,
+          /*FoundDecl=*/nullptr,
+          /*NamedDecl=*/TL.getTypePtr()->getTypeConstraintConcept(),
+          (TemplateId->NumArgs > 0
+               ? ASTTemplateArgumentListInfo::Create(Context, TemplateArgsInfo)
+               : nullptr));
+      TL.setConceptLoc(CL);
     }
     void VisitTagTypeLoc(TagTypeLoc TL) {
       TL.setNameLoc(DS.getTypeSpecTypeNameLoc());
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -41,6 +41,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <algorithm>
+#include <llvm-15/llvm/Analysis/AssumptionCache.h>
 #include <optional>
 
 using namespace llvm::omp;
@@ -783,6 +784,8 @@
 
   StmtResult TransformOMPExecutableDirective(OMPExecutableDirective *S);
 
+  // ActionResult<ConceptLoc *> TransformConceptLoc(const ConceptLoc *L);
+
 // FIXME: We use LLVM_ATTRIBUTE_NOINLINE because inlining causes a ridiculous
 // amount of stack usage with clang.
 #define STMT(Node, Parent)                        \
@@ -3597,6 +3600,8 @@
     return Result;
   }
 
+  /* NOTE(massberg) We need probably a RebuildConceptLoc here.*/
+
   /// \brief Build a new requires expression.
   ///
   /// By default, performs semantic analysis to build the new expression.
@@ -6846,15 +6851,28 @@
 
   AutoTypeLoc NewTL = TLB.push<AutoTypeLoc>(Result);
   NewTL.setNameLoc(TL.getNameLoc());
-  NewTL.setNestedNameSpecifierLoc(NewNestedNameSpec);
-  NewTL.setTemplateKWLoc(TL.getTemplateKWLoc());
-  NewTL.setConceptNameLoc(TL.getConceptNameLoc());
-  NewTL.setFoundDecl(TL.getFoundDecl());
   NewTL.setLAngleLoc(TL.getLAngleLoc());
   NewTL.setRAngleLoc(TL.getRAngleLoc());
   NewTL.setRParenLoc(TL.getRParenLoc());
-  for (unsigned I = 0; I < NewTL.getNumArgs(); ++I)
-    NewTL.setArgLocInfo(I, NewTemplateArgs.arguments()[I].getLocInfo());
+
+  if (T->isConstrained()) {
+    // FIXME: move to TransformConceptLoc
+    DeclarationNameInfo DNI = DeclarationNameInfo();
+    DNI.setLoc(TL.getConceptNameLoc());
+    if (T->isConstrained()) {
+      DNI.setName(TL.getTypePtr()->getTypeConstraintConcept()->getDeclName());
+      DNI.setInfo(TL.getTypePtr()->getTypeConstraintConcept()->getDeclName());
+    }
+    auto *CL = ConceptLoc::Create(
+        SemaRef.Context, NewNestedNameSpec, TL.getTemplateKWLoc(), DNI,
+        TL.getFoundDecl(),
+        (T->isConstrained() ? TL.getTypePtr()->getTypeConstraintConcept()
+                            : nullptr),
+        (NewTemplateArgs.size() > 0 ? ASTTemplateArgumentListInfo::Create(
+                                          SemaRef.Context, NewTemplateArgs)
+                                    : nullptr));
+    NewTL.setConceptLoc(CL);
+  }
 
   return Result;
 }
@@ -12869,6 +12887,21 @@
       &TransArgs);
 }
 
+/*template <typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformConceptLoc(const ConceptLoc *CL) {
+  const ASTTemplateArgumentListInfo *Old = CL->getTemplateArgsAsWritten();
+  TemplateArgumentListInfo TransArgs(Old->LAngleLoc, Old->RAngleLoc);
+  if (getDerived().TransformTemplateArguments(Old->getTemplateArgs(),
+                                              Old->NumTemplateArgs, TransArgs))
+    return ExprError;
+
+  return getDerived().RebuildConceptLoc(
+      CL->getNestedNameSpecifierLoc(), CL->getTemplateKWLoc(),
+      CL->getConceptNameInfo(), CL->getFoundDecl(), CL->getNamedConcept(),
+      &TransArgs);
+}*/
+
 template<typename Derived>
 ExprResult
 TreeTransform<Derived>::TransformRequiresExpr(RequiresExpr *E) {
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -6809,16 +6809,24 @@
 void TypeLocReader::VisitAutoTypeLoc(AutoTypeLoc TL) {
   TL.setNameLoc(readSourceLocation());
   if (Reader.readBool()) {
-    TL.setNestedNameSpecifierLoc(ReadNestedNameSpecifierLoc());
-    TL.setTemplateKWLoc(readSourceLocation());
-    TL.setConceptNameLoc(readSourceLocation());
-    TL.setFoundDecl(Reader.readDeclAs<NamedDecl>());
     TL.setLAngleLoc(readSourceLocation());
     TL.setRAngleLoc(readSourceLocation());
-    for (unsigned i = 0, e = TL.getNumArgs(); i != e; ++i)
-      TL.setArgLocInfo(
-          i, Reader.readTemplateArgumentLocInfo(
-                 TL.getTypePtr()->getTypeConstraintArguments()[i].getKind()));
+    // FIXME: Move to VisitConceptLoc()
+    TL.setDefaultLoc(readSourceLocation());
+    if (Reader.readBool()) {
+      auto NNS = ReadNestedNameSpecifierLoc();
+      auto TemplateKWLoc = readSourceLocation();
+      auto ConceptNameLoc = Reader.readDeclarationNameInfo();
+      auto FoundDecl = Reader.readDeclAs<NamedDecl>();
+      auto NamedConcept = Reader.readDeclAs<ConceptDecl>();
+
+      auto *CL = ConceptLoc::Create(
+          Reader.getContext(), NNS, TemplateKWLoc, ConceptNameLoc, FoundDecl,
+          NamedConcept,
+          (Reader.readBool() ? Reader.readASTTemplateArgumentListInfo()
+                             : nullptr));
+      TL.setConceptLoc(CL);
+    }
   }
   if (Reader.readBool())
     TL.setRParenLoc(readSourceLocation());
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2627,8 +2627,12 @@
     if (Record.readBool())
         ArgsAsWritten = Record.readASTTemplateArgumentListInfo();
     Expr *ImmediatelyDeclaredConstraint = Record.readExpr();
-    D->setTypeConstraint(NNS, DN, /*FoundDecl=*/nullptr, NamedConcept,
-                         ArgsAsWritten, ImmediatelyDeclaredConstraint);
+    auto *CL = ConceptLoc::Create(
+        Reader.getContext(), NNS,
+        SourceLocation{}, // What is the correct value here?
+        DN, /*FoundDecl=*/nullptr, NamedConcept, ArgsAsWritten);
+
+    D->setTypeConstraint(CL, ImmediatelyDeclaredConstraint);
     if ((D->ExpandedParameterPack = Record.readInt()))
       D->NumExpanded = Record.readInt();
   }
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -795,13 +795,16 @@
 void ASTStmtReader::VisitConceptSpecializationExpr(
         ConceptSpecializationExpr *E) {
   VisitExpr(E);
-  E->NestedNameSpec = Record.readNestedNameSpecifierLoc();
-  E->TemplateKWLoc = Record.readSourceLocation();
-  E->ConceptName = Record.readDeclarationNameInfo();
-  E->NamedConcept = readDeclAs<ConceptDecl>();
-  E->FoundDecl = Record.readDeclAs<NamedDecl>();
+  auto NestedNameSpec = Record.readNestedNameSpecifierLoc();
+  auto TemplateKWLoc = Record.readSourceLocation();
+  auto ConceptName = Record.readDeclarationNameInfo();
+  auto NamedConcept = readDeclAs<ConceptDecl>();
+  auto FoundDecl = Record.readDeclAs<NamedDecl>();
   E->SpecDecl = Record.readDeclAs<ImplicitConceptSpecializationDecl>();
-  E->ArgsAsWritten = Record.readASTTemplateArgumentListInfo();
+  auto ArgsAsWritten = Record.readASTTemplateArgumentListInfo();
+  E->Loc =
+      ConceptLoc::Create(Record.getContext(), NestedNameSpec, TemplateKWLoc,
+                         ConceptName, FoundDecl, NamedConcept, ArgsAsWritten);
   E->Satisfaction = E->isValueDependent() ? nullptr :
       ASTConstraintSatisfaction::Create(Record.getContext(),
                                         readConstraintSatisfaction(Record));
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -473,16 +473,23 @@
   addSourceLocation(TL.getNameLoc());
   Record.push_back(TL.isConstrained());
   if (TL.isConstrained()) {
-    Record.AddNestedNameSpecifierLoc(TL.getNestedNameSpecifierLoc());
-    addSourceLocation(TL.getTemplateKWLoc());
-    addSourceLocation(TL.getConceptNameLoc());
-    Record.AddDeclRef(TL.getFoundDecl());
     addSourceLocation(TL.getLAngleLoc());
     addSourceLocation(TL.getRAngleLoc());
-    for (unsigned I = 0; I < TL.getNumArgs(); ++I)
-      Record.AddTemplateArgumentLocInfo(
-          TL.getTypePtr()->getTypeConstraintArguments()[I].getKind(),
-          TL.getArgLocInfo(I));
+    Record.AddSourceLocation(TL.getDefaultLoc());
+
+    // FIXME: Move to VisitConceptLoc()
+    auto *CL = TL.getConceptLoc();
+    Record.push_back(CL != nullptr);
+    if (CL) {
+      Record.AddNestedNameSpecifierLoc(CL->getNestedNameSpecifierLoc());
+      Record.AddSourceLocation(CL->getTemplateKWLoc());
+      Record.AddDeclarationNameInfo(CL->getConceptNameInfo());
+      Record.AddDeclRef(CL->getFoundDecl());
+      Record.AddDeclRef(CL->getNamedConcept());
+      Record.push_back(CL->getTemplateArgsAsWritten() != nullptr);
+      if (CL->getTemplateArgsAsWritten())
+        Record.AddASTTemplateArgumentListInfo(CL->getTemplateArgsAsWritten());
+    }
   }
   Record.push_back(TL.isDecltypeAuto());
   if (TL.isDecltypeAuto())
diff --git a/clang/unittests/Tooling/RecursiveASTVisitorTests/Concept.cpp b/clang/unittests/Tooling/RecursiveASTVisitorTests/Concept.cpp
--- a/clang/unittests/Tooling/RecursiveASTVisitorTests/Concept.cpp
+++ b/clang/unittests/Tooling/RecursiveASTVisitorTests/Concept.cpp
@@ -29,12 +29,17 @@
     ++ConceptRequirementsTraversed;
     return ExpectedLocationVisitor::TraverseConceptRequirement(R);
   }
+  bool TraverseConceptLoc(const ConceptLoc *CL) {
+    ++ConceptLocsTraversed;
+    return ExpectedLocationVisitor::TraverseConceptLoc(CL);
+  }
 
   bool shouldVisitImplicitCode() { return ShouldVisitImplicitCode; }
 
   int ConceptSpecializationExprsVisited = 0;
   int TypeConstraintsTraversed = 0;
   int ConceptRequirementsTraversed = 0;
+  int ConceptLocsTraversed = 0;
   bool ShouldVisitImplicitCode = false;
 };
 
@@ -50,6 +55,7 @@
   EXPECT_EQ(1, Visitor.ConceptSpecializationExprsVisited);
   // Also check we traversed the TypeConstraint that produced the expr.
   EXPECT_EQ(1, Visitor.TypeConstraintsTraversed);
+  EXPECT_EQ(1, Visitor.ConceptLocsTraversed);
 
   Visitor = {}; // Don't visit implicit code now.
   EXPECT_TRUE(Visitor.runOver("template <typename T> concept Fooable = true;\n"
@@ -59,6 +65,7 @@
   // generated immediately declared expression.
   EXPECT_EQ(0, Visitor.ConceptSpecializationExprsVisited);
   EXPECT_EQ(1, Visitor.TypeConstraintsTraversed);
+  EXPECT_EQ(1, Visitor.ConceptLocsTraversed);
 
   Visitor = {};
   EXPECT_TRUE(Visitor.runOver("template <class T> concept A = true;\n"
@@ -70,6 +77,7 @@
                               "};",
                               ConceptVisitor::Lang_CXX2a));
   EXPECT_EQ(3, Visitor.ConceptRequirementsTraversed);
+  EXPECT_EQ(1, Visitor.ConceptLocsTraversed);
 }
 
 struct VisitDeclOnlyOnce : ExpectedLocationVisitor<VisitDeclOnlyOnce> {