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
@@ -59,6 +59,13 @@
   static void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &C,
                       const NamedDecl *ConstraintOwner,
                       ArrayRef<TemplateArgument> TemplateArgs);
+
+  bool HasSubstitutionFailure() {
+    for (const auto &Detail : Details)
+      if (Detail.second.dyn_cast<SubstitutionDiagnostic *>())
+        return true;
+    return false;
+  }
 };
 
 /// Pairs of unsatisfied atomic constraint expressions along with the
@@ -91,9 +98,13 @@
 
   ASTConstraintSatisfaction(const ASTContext &C,
                             const ConstraintSatisfaction &Satisfaction);
+  ASTConstraintSatisfaction(const ASTContext &C,
+                            const ASTConstraintSatisfaction &Satisfaction);
 
   static ASTConstraintSatisfaction *
   Create(const ASTContext &C, const ConstraintSatisfaction &Satisfaction);
+  static ASTConstraintSatisfaction *
+  Rebuild(const ASTContext &C, const ASTConstraintSatisfaction &Satisfaction);
 };
 
 /// \brief Common data class for constructs that reference concepts with
diff --git a/clang/include/clang/AST/ASTNodeTraverser.h b/clang/include/clang/AST/ASTNodeTraverser.h
--- a/clang/include/clang/AST/ASTNodeTraverser.h
+++ b/clang/include/clang/AST/ASTNodeTraverser.h
@@ -246,7 +246,7 @@
                     .getTypeConstraint()
                     ->getImmediatelyDeclaredConstraint());
       } else if (auto *NR = dyn_cast<concepts::NestedRequirement>(R)) {
-        if (!NR->isSubstitutionFailure())
+        if (!NR->hasInvalidConstraint())
           Visit(NR->getConstraintExpr());
       }
     });
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
@@ -24,6 +24,7 @@
 #include "clang/AST/TemplateBase.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/SourceLocation.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TrailingObjects.h"
 #include <utility>
 #include <string>
@@ -401,57 +402,61 @@
 /// \brief A requires-expression requirement which is satisfied when a general
 /// constraint expression is satisfied ('nested' requirements).
 class NestedRequirement : public Requirement {
-  llvm::PointerUnion<Expr *, SubstitutionDiagnostic *> Value;
+  Expr *Constraint = nullptr;
   const ASTConstraintSatisfaction *Satisfaction = nullptr;
+  bool HasInvalidConstraint = false;
+  StringRef InvalidConstraintEntity;
 
 public:
   friend ASTStmtReader;
   friend ASTStmtWriter;
 
-  NestedRequirement(SubstitutionDiagnostic *SubstDiag) :
-      Requirement(RK_Nested, /*IsDependent=*/false,
-                  /*ContainsUnexpandedParameterPack*/false,
-                  /*IsSatisfied=*/false), Value(SubstDiag) {}
-
-  NestedRequirement(Expr *Constraint) :
-      Requirement(RK_Nested, /*IsDependent=*/true,
-                  Constraint->containsUnexpandedParameterPack()),
-      Value(Constraint) {
+  NestedRequirement(Expr *Constraint)
+      : Requirement(RK_Nested, /*IsDependent=*/true,
+                    Constraint->containsUnexpandedParameterPack()),
+        Constraint(Constraint) {
     assert(Constraint->isInstantiationDependent() &&
            "Nested requirement with non-dependent constraint must be "
            "constructed with a ConstraintSatisfaction object");
   }
 
   NestedRequirement(ASTContext &C, Expr *Constraint,
-                    const ConstraintSatisfaction &Satisfaction) :
-      Requirement(RK_Nested, Constraint->isInstantiationDependent(),
-                  Constraint->containsUnexpandedParameterPack(),
-                  Satisfaction.IsSatisfied),
-      Value(Constraint),
-      Satisfaction(ASTConstraintSatisfaction::Create(C, Satisfaction)) {}
-
-  bool isSubstitutionFailure() const {
-    return Value.is<SubstitutionDiagnostic *>();
-  }
-
-  SubstitutionDiagnostic *getSubstitutionDiagnostic() const {
-    assert(isSubstitutionFailure() &&
-           "getSubstitutionDiagnostic() may not be called when there was no "
-           "substitution failure.");
-    return Value.get<SubstitutionDiagnostic *>();
+                    const ConstraintSatisfaction &Satisfaction)
+      : Requirement(RK_Nested, Constraint->isInstantiationDependent(),
+                    Constraint->containsUnexpandedParameterPack(),
+                    Satisfaction.IsSatisfied),
+        Constraint(Constraint),
+        Satisfaction(ASTConstraintSatisfaction::Create(C, Satisfaction)) {}
+
+  NestedRequirement(StringRef InvalidConstraintEntity,
+                    const ASTConstraintSatisfaction *Satisfaction)
+      : Requirement(RK_Nested,
+                    /*IsDependent=*/false,
+                    /*ContainsUnexpandedParameterPack*/ false,
+                    Satisfaction->IsSatisfied),
+        Satisfaction(Satisfaction), HasInvalidConstraint(true),
+        InvalidConstraintEntity(InvalidConstraintEntity) {}
+
+  NestedRequirement(ASTContext &C, StringRef InvalidConstraintEntity,
+                    const ConstraintSatisfaction &Satisfaction)
+      : NestedRequirement(InvalidConstraintEntity,
+                          ASTConstraintSatisfaction::Create(C, Satisfaction)) {}
+
+  bool hasInvalidConstraint() const { return HasInvalidConstraint; }
+
+  StringRef getInvalidConstraintEntity() {
+    assert(hasInvalidConstraint());
+    return InvalidConstraintEntity;
   }
 
   Expr *getConstraintExpr() const {
-    assert(!isSubstitutionFailure() && "getConstraintExpr() may not be called "
-                                       "on nested requirements with "
-                                       "substitution failures.");
-    return Value.get<Expr *>();
+    assert(!hasInvalidConstraint() &&
+           "getConstraintExpr() may not be called "
+           "on nested requirements with invalid constraint.");
+    return Constraint;
   }
 
   const ASTConstraintSatisfaction &getConstraintSatisfaction() const {
-    assert(!isSubstitutionFailure() && "getConstraintSatisfaction() may not be "
-                                       "called on nested requirements with "
-                                       "substitution failures.");
     return *Satisfaction;
   }
 
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
@@ -600,7 +600,7 @@
 template <typename Derived>
 bool RecursiveASTVisitor<Derived>::TraverseConceptNestedRequirement(
     concepts::NestedRequirement *R) {
-  if (!R->isSubstitutionFailure())
+  if (!R->hasInvalidConstraint())
     return getDerived().TraverseStmt(R->getConstraintExpr());
   return true;
 }
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2888,7 +2888,7 @@
 def note_type_requirement_unknown_substitution_error : Note<
   "%select{and|because}0 '%1' would be invalid">;
 def note_nested_requirement_substitution_error : Note<
-  "%select{and|because}0 '%1' would be invalid: %2">;
+  "%select{and|because}0 '%1' would be invalid%2">;
 def note_nested_requirement_unknown_substitution_error : Note<
   "%select{and|because}0 '%1' would be invalid">;
 def note_ambiguous_atomic_constraints : Note<
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -8459,8 +8459,8 @@
       concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
   concepts::NestedRequirement *BuildNestedRequirement(Expr *E);
   concepts::NestedRequirement *
-  BuildNestedRequirement(
-      concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
+  BuildNestedRequirement(StringRef InvalidConstraintEntity,
+                         const ASTConstraintSatisfaction &Satisfaction);
   ExprResult ActOnRequiresExpr(SourceLocation RequiresKWLoc,
                                RequiresExprBodyDecl *Body,
                                ArrayRef<ParmVarDecl *> LocalParameters,
diff --git a/clang/lib/AST/ASTConcept.cpp b/clang/lib/AST/ASTConcept.cpp
--- a/clang/lib/AST/ASTConcept.cpp
+++ b/clang/lib/AST/ASTConcept.cpp
@@ -19,32 +19,48 @@
 #include "llvm/ADT/FoldingSet.h"
 using namespace clang;
 
+namespace {
+void CreatUnsatisfiedConstraintRecord(
+    const ASTContext &C, const UnsatisfiedConstraintRecord &Detail,
+    UnsatisfiedConstraintRecord *TrailingObject) {
+  if (Detail.second.is<Expr *>())
+    new (TrailingObject) UnsatisfiedConstraintRecord{
+        Detail.first,
+        UnsatisfiedConstraintRecord::second_type(Detail.second.get<Expr *>())};
+  else {
+    auto &SubstitutionDiagnostic =
+        *Detail.second.get<std::pair<SourceLocation, StringRef> *>();
+    unsigned MessageSize = SubstitutionDiagnostic.second.size();
+    char *Mem = new (C) char[MessageSize];
+    memcpy(Mem, SubstitutionDiagnostic.second.data(), MessageSize);
+    auto *NewSubstDiag = new (C) std::pair<SourceLocation, StringRef>(
+        SubstitutionDiagnostic.first, StringRef(Mem, MessageSize));
+    new (TrailingObject) UnsatisfiedConstraintRecord{
+        Detail.first, UnsatisfiedConstraintRecord::second_type(NewSubstDiag)};
+  }
+}
+} // namespace
+
 ASTConstraintSatisfaction::ASTConstraintSatisfaction(
     const ASTContext &C, const ConstraintSatisfaction &Satisfaction)
     : NumRecords{Satisfaction.Details.size()},
       IsSatisfied{Satisfaction.IsSatisfied}, ContainsErrors{
                                                  Satisfaction.ContainsErrors} {
-  for (unsigned I = 0; I < NumRecords; ++I) {
-    auto &Detail = Satisfaction.Details[I];
-    if (Detail.second.is<Expr *>())
-      new (getTrailingObjects<UnsatisfiedConstraintRecord>() + I)
-         UnsatisfiedConstraintRecord{Detail.first,
-                                     UnsatisfiedConstraintRecord::second_type(
-                                         Detail.second.get<Expr *>())};
-    else {
-      auto &SubstitutionDiagnostic =
-          *Detail.second.get<std::pair<SourceLocation, StringRef> *>();
-      unsigned MessageSize = SubstitutionDiagnostic.second.size();
-      char *Mem = new (C) char[MessageSize];
-      memcpy(Mem, SubstitutionDiagnostic.second.data(), MessageSize);
-      auto *NewSubstDiag = new (C) std::pair<SourceLocation, StringRef>(
-          SubstitutionDiagnostic.first, StringRef(Mem, MessageSize));
-      new (getTrailingObjects<UnsatisfiedConstraintRecord>() + I)
-         UnsatisfiedConstraintRecord{Detail.first,
-                                     UnsatisfiedConstraintRecord::second_type(
-                                         NewSubstDiag)};
-    }
-  }
+  for (unsigned I = 0; I < NumRecords; ++I)
+    CreatUnsatisfiedConstraintRecord(
+        C, Satisfaction.Details[I],
+        getTrailingObjects<UnsatisfiedConstraintRecord>() + I);
+}
+
+ASTConstraintSatisfaction::ASTConstraintSatisfaction(
+    const ASTContext &C, const ASTConstraintSatisfaction &Satisfaction)
+    : NumRecords{Satisfaction.NumRecords},
+      IsSatisfied{Satisfaction.IsSatisfied},
+      ContainsErrors{Satisfaction.ContainsErrors} {
+  for (unsigned I = 0; I < NumRecords; ++I)
+    CreatUnsatisfiedConstraintRecord(
+        C, *(Satisfaction.begin() + I),
+        getTrailingObjects<UnsatisfiedConstraintRecord>() + I);
 }
 
 ASTConstraintSatisfaction *
@@ -57,6 +73,14 @@
   return new (Mem) ASTConstraintSatisfaction(C, Satisfaction);
 }
 
+ASTConstraintSatisfaction *ASTConstraintSatisfaction::Rebuild(
+    const ASTContext &C, const ASTConstraintSatisfaction &Satisfaction) {
+  std::size_t size =
+      totalSizeToAlloc<UnsatisfiedConstraintRecord>(Satisfaction.NumRecords);
+  void *Mem = C.Allocate(size, alignof(ASTConstraintSatisfaction));
+  return new (Mem) ASTConstraintSatisfaction(C, Satisfaction);
+}
+
 void ConstraintSatisfaction::Profile(
     llvm::FoldingSetNodeID &ID, const ASTContext &C,
     const NamedDecl *ConstraintOwner, ArrayRef<TemplateArgument> TemplateArgs) {
diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -2516,7 +2516,7 @@
     } else {
       auto *NestedReq = cast<concepts::NestedRequirement>(Req);
       OS << "requires ";
-      if (NestedReq->isSubstitutionFailure())
+      if (NestedReq->hasInvalidConstraint())
         OS << "<<error-expression>>";
       else
         PrintExpr(NestedReq->getConstraintExpr());
diff --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -1610,8 +1610,8 @@
     } else {
       ID.AddInteger(concepts::Requirement::RK_Nested);
       auto *NestedReq = cast<concepts::NestedRequirement>(Req);
-      ID.AddBoolean(NestedReq->isSubstitutionFailure());
-      if (!NestedReq->isSubstitutionFailure())
+      ID.AddBoolean(NestedReq->hasInvalidConstraint());
+      if (!NestedReq->hasInvalidConstraint())
         Visit(NestedReq->getConstraintExpr());
     }
   }
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -169,7 +169,8 @@
       //    is checked. If that is satisfied, the disjunction is satisfied.
       //    Otherwise, the disjunction is satisfied if and only if the second
       //    operand is satisfied.
-      return BO.recreateBinOp(S, LHSRes);
+      // LHS is instantiated while RHS is not. Skip creating invalid BinaryOp.
+      return LHSRes;
 
     if (BO.isAnd() && !IsLHSSatisfied)
       // [temp.constr.op] p2
@@ -178,7 +179,8 @@
       //    is checked. If that is not satisfied, the conjunction is not
       //    satisfied. Otherwise, the conjunction is satisfied if and only if
       //    the second operand is satisfied.
-      return BO.recreateBinOp(S, LHSRes);
+      // LHS is instantiated while RHS is not. Skip creating invalid BinaryOp.
+      return LHSRes;
 
     ExprResult RHSRes = calculateConstraintSatisfaction(
         S, BO.getRHS(), Satisfaction, std::forward<AtomicEvaluator>(Evaluator));
@@ -286,7 +288,8 @@
           // bool if this is the operand of an '&&' or '||'. For example, we
           // might lose an lvalue-to-rvalue conversion here. If so, put it back
           // before we try to evaluate.
-          if (!SubstitutedExpression.isInvalid())
+          if (SubstitutedExpression.isUsable() &&
+              !SubstitutedExpression.isInvalid())
             SubstitutedExpression =
                 S.PerformContextuallyConvertToBool(SubstitutedExpression.get());
           if (SubstitutedExpression.isInvalid() || Trap.hasErrorOccurred()) {
@@ -853,31 +856,28 @@
     return;
   }
 }
+static void diagnoseWellFormedUnsatisfiedConstraintExpr(Sema &S,
+                                                        Expr *SubstExpr,
+                                                        bool First = true);
 
 static void diagnoseUnsatisfiedRequirement(Sema &S,
                                            concepts::NestedRequirement *Req,
                                            bool First) {
-  if (Req->isSubstitutionFailure()) {
-    concepts::Requirement::SubstitutionDiagnostic *SubstDiag =
-        Req->getSubstitutionDiagnostic();
-    if (!SubstDiag->DiagMessage.empty())
-      S.Diag(SubstDiag->DiagLoc,
-             diag::note_nested_requirement_substitution_error)
-             << (int)First << SubstDiag->SubstitutedEntity
-             << SubstDiag->DiagMessage;
+  using SubstitutionDiagnostic = std::pair<SourceLocation, StringRef>;
+  for (auto &Pair : Req->getConstraintSatisfaction()) {
+    if (auto *SubstDiag = Pair.second.dyn_cast<SubstitutionDiagnostic *>())
+      S.Diag(SubstDiag->first, diag::note_nested_requirement_substitution_error)
+          << (int)First << Req->getInvalidConstraintEntity() << SubstDiag->second;
     else
-      S.Diag(SubstDiag->DiagLoc,
-             diag::note_nested_requirement_unknown_substitution_error)
-          << (int)First << SubstDiag->SubstitutedEntity;
-    return;
+      diagnoseWellFormedUnsatisfiedConstraintExpr(
+          S, Pair.second.dyn_cast<Expr *>(), First);
+    First = false;
   }
-  S.DiagnoseUnsatisfiedConstraint(Req->getConstraintSatisfaction(), First);
 }
 
-
 static void diagnoseWellFormedUnsatisfiedConstraintExpr(Sema &S,
                                                         Expr *SubstExpr,
-                                                        bool First = true) {
+                                                        bool First) {
   SubstExpr = SubstExpr->IgnoreParenImpCasts();
   if (BinaryOperator *BO = dyn_cast<BinaryOperator>(SubstExpr)) {
     switch (BO->getOpcode()) {
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -9026,9 +9026,11 @@
 }
 
 concepts::NestedRequirement *
-Sema::BuildNestedRequirement(
-    concepts::Requirement::SubstitutionDiagnostic *SubstDiag) {
-  return new (Context) concepts::NestedRequirement(SubstDiag);
+Sema::BuildNestedRequirement(StringRef InvalidConstraintEntity,
+                       const ASTConstraintSatisfaction &Satisfaction) {
+  return new (Context) concepts::NestedRequirement(
+      InvalidConstraintEntity,
+      ASTConstraintSatisfaction::Rebuild(Context, Satisfaction));
 }
 
 RequiresExprBodyDecl *
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
@@ -19,6 +19,7 @@
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprConcepts.h"
 #include "clang/AST/PrettyDeclStackTrace.h"
+#include "clang/AST/Type.h"
 #include "clang/AST/TypeVisitor.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/Stack.h"
@@ -26,11 +27,13 @@
 #include "clang/Sema/DeclSpec.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
+#include "clang/Sema/Sema.h"
 #include "clang/Sema/SemaConcept.h"
 #include "clang/Sema/SemaInternal.h"
 #include "clang/Sema/Template.h"
 #include "clang/Sema/TemplateDeduction.h"
 #include "clang/Sema/TemplateInstCallback.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TimeProfiler.h"
 
 using namespace clang;
@@ -2305,10 +2308,10 @@
     concepts::NestedRequirement *Req) {
   if (!Req->isDependent() && !AlwaysRebuild())
     return Req;
-  if (Req->isSubstitutionFailure()) {
+  if (Req->hasInvalidConstraint()) {
     if (AlwaysRebuild())
-      return RebuildNestedRequirement(
-          Req->getSubstitutionDiagnostic());
+      return RebuildNestedRequirement(Req->getInvalidConstraintEntity(),
+                                      Req->getConstraintSatisfaction());
     return Req;
   }
   Sema::InstantiatingTemplate ReqInst(SemaRef,
@@ -2328,36 +2331,29 @@
         Req->getConstraintExpr()->getSourceRange());
     if (ConstrInst.isInvalid())
       return nullptr;
-    TransConstraint = TransformExpr(Req->getConstraintExpr());
-    if (!TransConstraint.isInvalid()) {
-      bool CheckSucceeded =
-          SemaRef.CheckConstraintExpression(TransConstraint.get());
-      (void)CheckSucceeded;
-      assert((CheckSucceeded || Trap.hasErrorOccurred()) &&
-                                   "CheckConstraintExpression failed, but "
-                                   "did not produce a SFINAE error");
-    }
-    // Use version of CheckConstraintSatisfaction that does no substitutions.
-    if (!TransConstraint.isInvalid() &&
-        !TransConstraint.get()->isInstantiationDependent() &&
-        !Trap.hasErrorOccurred()) {
-      bool CheckFailed = SemaRef.CheckConstraintSatisfaction(
-          TransConstraint.get(), Satisfaction);
-      (void)CheckFailed;
-      assert((!CheckFailed || Trap.hasErrorOccurred()) &&
-                                 "CheckConstraintSatisfaction failed, "
-                                 "but did not produce a SFINAE error");
-    }
-    if (TransConstraint.isInvalid() || Trap.hasErrorOccurred())
-      return RebuildNestedRequirement(createSubstDiag(SemaRef, Info,
-          [&] (llvm::raw_ostream& OS) {
-              Req->getConstraintExpr()->printPretty(OS, nullptr,
-                                                    SemaRef.getPrintingPolicy());
-          }));
+    llvm::SmallVector<Expr *> Result;
+    if (!SemaRef.CheckConstraintSatisfaction(
+            nullptr, {Req->getConstraintExpr()}, Result, TemplateArgs,
+            Req->getConstraintExpr()->getSourceRange(), Satisfaction))
+      TransConstraint = Result[0];
+    assert(!Trap.hasErrorOccurred() && "Substitution failures must be handled "
+                                       "by CheckConstraintSatisfaction.");
   }
-  if (TransConstraint.get()->isInstantiationDependent())
+  if (TransConstraint.isUsable() &&
+      TransConstraint.get()->isInstantiationDependent())
     return new (SemaRef.Context)
         concepts::NestedRequirement(TransConstraint.get());
+  if (TransConstraint.isInvalid() || !TransConstraint.get() ||
+      Satisfaction.HasSubstitutionFailure()) {
+    SmallString<128> Entity;
+    llvm::raw_svector_ostream OS(Entity);
+    Req->getConstraintExpr()->printPretty(OS, nullptr,
+                                          SemaRef.getPrintingPolicy());
+    char *EntityBuf = new (SemaRef.Context) char[Entity.size()];
+    std::copy(Entity.begin(), Entity.end(), EntityBuf);
+    return new (SemaRef.Context) concepts::NestedRequirement(
+        SemaRef.Context, StringRef(EntityBuf, Entity.size()), Satisfaction);
+  }
   return new (SemaRef.Context) concepts::NestedRequirement(
       SemaRef.Context, TransConstraint.get(), Satisfaction);
 }
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
@@ -3517,9 +3517,10 @@
   }
 
   concepts::NestedRequirement *
-  RebuildNestedRequirement(
-      concepts::Requirement::SubstitutionDiagnostic *SubstDiag) {
-    return SemaRef.BuildNestedRequirement(SubstDiag);
+  RebuildNestedRequirement(StringRef InvalidConstraintEntity,
+                           const ASTConstraintSatisfaction &Satisfaction) {
+    return SemaRef.BuildNestedRequirement(InvalidConstraintEntity,
+                                          Satisfaction);
   }
 
   concepts::NestedRequirement *RebuildNestedRequirement(Expr *Constraint) {
@@ -12761,12 +12762,13 @@
 concepts::NestedRequirement *
 TreeTransform<Derived>::TransformNestedRequirement(
     concepts::NestedRequirement *Req) {
-  if (Req->isSubstitutionFailure()) {
-    if (getDerived().AlwaysRebuild())
-      return getDerived().RebuildNestedRequirement(
-          Req->getSubstitutionDiagnostic());
-    return Req;
-  }
+  // if (Req->hasInvalidConstraint()) {
+  //   if (getDerived().AlwaysRebuild())
+  //     return getDerived().RebuildNestedRequirement(
+  //         Req->getSubstitutionDiagnostic());
+  //   return Req;
+  // }
+  assert(!Req->hasInvalidConstraint());
   ExprResult TransConstraint =
       getDerived().TransformExpr(Req->getConstraintExpr());
   if (TransConstraint.isInvalid())
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
@@ -895,9 +895,17 @@
                   std::move(*Req));
       } break;
       case concepts::Requirement::RK_Nested: {
-        if (/* IsSubstitutionDiagnostic */Record.readInt()) {
+        bool HasInvalidConstraint = Record.readInt();
+        if (HasInvalidConstraint) {
+          std::string InvalidConstraint = Record.readString();
+          char *InvalidConstraintBuf =
+              new (Record.getContext()) char[InvalidConstraint.size()];
+          std::copy(InvalidConstraint.begin(), InvalidConstraint.end(),
+                    InvalidConstraintBuf);
           R = new (Record.getContext()) concepts::NestedRequirement(
-              readSubstitutionDiagnostic(Record));
+              Record.getContext(),
+              StringRef(InvalidConstraintBuf, InvalidConstraint.size()),
+              readConstraintSatisfaction(Record));
           break;
         }
         Expr *E = Record.readExpr();
diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -493,12 +493,12 @@
     } else {
       auto *NestedReq = cast<concepts::NestedRequirement>(R);
       Record.push_back(concepts::Requirement::RK_Nested);
-      Record.push_back(NestedReq->isSubstitutionFailure());
-      if (NestedReq->isSubstitutionFailure()){
-        addSubstitutionDiagnostic(Record,
-                                  NestedReq->getSubstitutionDiagnostic());
+      Record.push_back(NestedReq->hasInvalidConstraint());
+      if (NestedReq->hasInvalidConstraint()) {
+        Record.AddString(NestedReq->getInvalidConstraintEntity());
+        addConstraintSatisfaction(Record, *NestedReq->Satisfaction);
       } else {
-        Record.AddStmt(NestedReq->Value.get<Expr *>());
+        Record.AddStmt(NestedReq->getConstraintExpr());
         if (!NestedReq->isDependent())
           addConstraintSatisfaction(Record, *NestedReq->Satisfaction);
       }
diff --git a/clang/test/CXX/expr/expr.prim/expr.prim.req/nested-requirement.cpp b/clang/test/CXX/expr/expr.prim/expr.prim.req/nested-requirement.cpp
--- a/clang/test/CXX/expr/expr.prim/expr.prim.req/nested-requirement.cpp
+++ b/clang/test/CXX/expr/expr.prim/expr.prim.req/nested-requirement.cpp
@@ -51,3 +51,115 @@
   X.next();
 };
 
+namespace SubstitutionFailureNestedRequires {
+template<class T>  concept True = true;
+template<class T>  concept False = false;
+
+struct S { double value; };
+
+template <class T>
+concept Pipes = requires (T x) {
+   requires True<decltype(x.value)> || True<T> || False<T>;
+   requires False<T> || True<T> || True<decltype(x.value)>;
+};
+
+template <class T>
+concept Amps1 = requires (T x) {
+   requires True<decltype(x.value)> && True<T> && !False<T>; // #Amps1
+};
+template <class T>
+concept Amps2 = requires (T x) {
+   requires True<T> && True<decltype(x.value)>;
+};
+
+static_assert(Pipes<S>);
+static_assert(Pipes<double>);
+
+static_assert(Amps1<S>);
+static_assert(!Amps1<double>);
+
+static_assert(Amps2<S>);
+static_assert(!Amps2<double>);
+
+template<class T>
+void foo1() requires requires (T x) { // #foo1
+  requires
+  True<decltype(x.value)> // #foo1Value
+  && True<T>;
+} {}
+template<class T> void fooPipes() requires Pipes<T> {}
+template<class T> void fooAmps1() requires Amps1<T> {} // #fooAmps1
+void foo() {
+  foo1<S>();
+  foo1<int>(); // expected-error {{no matching function for call to 'foo1'}}
+  // expected-note@#foo1Value {{because 'True<decltype(x.value)> && True<T>' would be invalid: member reference base type 'int' is not a structure or union}}
+  // expected-note@#foo1 {{candidate template ignored: constraints not satisfied [with T = int]}}
+  fooPipes<S>();
+  fooPipes<int>();
+  fooAmps1<S>();
+  fooAmps1<int>(); // expected-error {{no matching function for call to 'fooAmps1'}}
+  // expected-note@#fooAmps1 {{candidate template ignored: constraints not satisfied [with T = int]}}
+  // expected-note@#fooAmps1 {{because 'int' does not satisfy 'Amps1'}}
+  // expected-note@#Amps1 {{because 'True<decltype(x.value)> && True<T> && !False<T>' would be invalid: member reference base type 'int' is not a structure or union}}
+}
+
+template<class T>
+concept HasNoValue = requires (T x) {
+  requires !True<decltype(x.value)> && True<T>;
+};
+// FIXME: 'int' does not satisfy 'HasNoValue' currently since `!True<decltype(x.value)>` is an invalid expression.
+// But, in principle, it should be constant-evaluated to true.
+// This happens also for requires expression and is not restricted to nested requirement.
+static_assert(!HasNoValue<int>);
+static_assert(!HasNoValue<S>);
+
+template<class T> constexpr bool NotAConceptTrue = true;
+template <class T>
+concept SFinNestedRequires = requires (T x) {
+    // SF in a non-concept specialisation should also be evaluated to false.
+   requires NotAConceptTrue<decltype(x.value)> || NotAConceptTrue<T>;
+};
+static_assert(SFinNestedRequires<int>);
+static_assert(SFinNestedRequires<S>);
+template <class T>
+void foo() requires SFinNestedRequires<T> {}
+void bar() {
+  foo<int>();
+  foo<S>();
+}
+namespace ErrorExpressions_NotSF {
+template<typename T> struct X { static constexpr bool value = T::value; }; // #X_Value
+struct True { static constexpr bool value = true; };
+struct False { static constexpr bool value = false; };
+template<typename T> concept C = true;
+template<typename T> concept F = false;
+
+template<typename T> requires requires(T) { requires C<T> || X<T>::value; } void foo();
+
+template<typename T> requires requires(T) { requires C<T> && X<T>::value; } void bar(); // #bar
+template<typename T> requires requires(T) { requires F<T> || (X<T>::value && C<T>); } void baz();
+
+void func() {
+  foo<True>();
+  foo<False>();
+  foo<int>();
+
+  bar<True>();
+  bar<False>();
+  // expected-error@-1 {{no matching function for call to 'bar'}}
+  // expected-note@#bar {{while substituting template arguments into constraint expression here}}
+  // expected-note@#bar {{while checking the satisfaction of nested requirement requested here}}
+  // expected-note@#bar {{candidate template ignored: constraints not satisfied [with T = False]}}
+  // expected-note@#bar {{because 'X<False>::value' evaluated to false}}
+
+  bar<int>();
+  // expected-note@-1 {{while checking constraint satisfaction for template 'bar<int>' required here}} \
+  // expected-note@-1 {{in instantiation of function template specialization}}
+  // expected-note@#bar {{in instantiation of static data member}}
+  // expected-note@#bar {{in instantiation of requirement here}}
+  // expected-note@#bar {{while checking the satisfaction of nested requirement requested here}}
+  // expected-note@#bar {{while substituting template arguments into constraint expression here}}
+  // expected-error@#X_Value {{type 'int' cannot be used prior to '::' because it has no members}}
+}
+}
+}
diff --git a/clang/test/PCH/cxx2a-requires-expr.cpp b/clang/test/PCH/cxx2a-requires-expr.cpp
--- a/clang/test/PCH/cxx2a-requires-expr.cpp
+++ b/clang/test/PCH/cxx2a-requires-expr.cpp
@@ -12,12 +12,13 @@
 
 template<typename T>
 bool f() {
-  // CHECK: requires (T t) { t++; { t++ } noexcept -> C; { t++ } -> C2<int>; typename T::a; requires T::val; };
+  // CHECK: requires (T t) { t++; { t++ } noexcept -> C; { t++ } -> C2<int>; typename T::a; requires T::val; requires C<typename T::val> || (C<typename T::val> || C<T>); };
   return requires (T t) {
     t++;
     { t++ } noexcept -> C;
     { t++ } -> C2<int>;
     typename T::a;
     requires T::val;
+    requires C<typename T::val> || (C<typename T::val> || C<T>);
   };
 }
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -1374,7 +1374,7 @@
   }
   case Requirement::RK_Nested: {
     const NestedRequirement &NR = cast<NestedRequirement>(R);
-    if (!NR.isSubstitutionFailure()) {
+    if (!NR.hasInvalidConstraint()) {
       if (Visit(NR.getConstraintExpr()))
         return true;
     }