diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 8c312c9d2c5a1..dff336f2ff2dd 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -18,7 +18,6 @@
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/PrettyDeclStackTrace.h"
-#include "clang/AST/TypeVisitor.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/Stack.h"
 #include "clang/Sema/DeclSpec.h"
@@ -2146,94 +2145,6 @@ void Sema::SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
   UpdateExceptionSpec(New, ESI);
 }
 
-namespace {
-
-  struct GetContainedInventedTypeParmVisitor :
-    public TypeVisitor<GetContainedInventedTypeParmVisitor,
-                       TemplateTypeParmDecl *> {
-    using TypeVisitor<GetContainedInventedTypeParmVisitor,
-                      TemplateTypeParmDecl *>::Visit;
-
-    TemplateTypeParmDecl *Visit(QualType T) {
-      if (T.isNull())
-        return nullptr;
-      return Visit(T.getTypePtr());
-    }
-    // The deduced type itself.
-    TemplateTypeParmDecl *VisitTemplateTypeParmType(
-        const TemplateTypeParmType *T) {
-      if (!T->getDecl()->isImplicit())
-        return nullptr;
-      return T->getDecl();
-    }
-
-    // Only these types can contain 'auto' types, and subsequently be replaced
-    // by references to invented parameters.
-
-    TemplateTypeParmDecl *VisitElaboratedType(const ElaboratedType *T) {
-      return Visit(T->getNamedType());
-    }
-
-    TemplateTypeParmDecl *VisitPointerType(const PointerType *T) {
-      return Visit(T->getPointeeType());
-    }
-
-    TemplateTypeParmDecl *VisitBlockPointerType(const BlockPointerType *T) {
-      return Visit(T->getPointeeType());
-    }
-
-    TemplateTypeParmDecl *VisitReferenceType(const ReferenceType *T) {
-      return Visit(T->getPointeeTypeAsWritten());
-    }
-
-    TemplateTypeParmDecl *VisitMemberPointerType(const MemberPointerType *T) {
-      return Visit(T->getPointeeType());
-    }
-
-    TemplateTypeParmDecl *VisitArrayType(const ArrayType *T) {
-      return Visit(T->getElementType());
-    }
-
-    TemplateTypeParmDecl *VisitDependentSizedExtVectorType(
-      const DependentSizedExtVectorType *T) {
-      return Visit(T->getElementType());
-    }
-
-    TemplateTypeParmDecl *VisitVectorType(const VectorType *T) {
-      return Visit(T->getElementType());
-    }
-
-    TemplateTypeParmDecl *VisitFunctionProtoType(const FunctionProtoType *T) {
-      return VisitFunctionType(T);
-    }
-
-    TemplateTypeParmDecl *VisitFunctionType(const FunctionType *T) {
-      return Visit(T->getReturnType());
-    }
-
-    TemplateTypeParmDecl *VisitParenType(const ParenType *T) {
-      return Visit(T->getInnerType());
-    }
-
-    TemplateTypeParmDecl *VisitAttributedType(const AttributedType *T) {
-      return Visit(T->getModifiedType());
-    }
-
-    TemplateTypeParmDecl *VisitMacroQualifiedType(const MacroQualifiedType *T) {
-      return Visit(T->getUnderlyingType());
-    }
-
-    TemplateTypeParmDecl *VisitAdjustedType(const AdjustedType *T) {
-      return Visit(T->getOriginalType());
-    }
-
-    TemplateTypeParmDecl *VisitPackExpansionType(const PackExpansionType *T) {
-      return Visit(T->getPattern());
-    }
-  };
-
-} // namespace
-
 ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm,
                             const MultiLevelTemplateArgumentList &TemplateArgs,
                                     int indexAdjustment,
@@ -2281,41 +2192,6 @@ ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm,
     return nullptr;
   }
 
-  // In abbreviated templates, TemplateTypeParmDecls with possible
-  // TypeConstraints are created when the parameter list is originally parsed.
-  // The TypeConstraints can therefore reference other functions parameters in
-  // the abbreviated function template, which is why we must instantiate them
-  // here, when the instantiated versions of those referenced parameters are in
-  // scope.
-  if (TemplateTypeParmDecl *TTP =
-          GetContainedInventedTypeParmVisitor().Visit(OldDI->getType())) {
-    if (const TypeConstraint *TC = TTP->getTypeConstraint()) {
-      // TODO: Concepts: do not instantiate the constraint (delayed constraint
-      // substitution)
-      const ASTTemplateArgumentListInfo *TemplArgInfo
-        = TC->getTemplateArgsAsWritten();
-      TemplateArgumentListInfo InstArgs;
-
-      if (TemplArgInfo) {
-        InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
-        InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
-        if (Subst(TemplArgInfo->getTemplateArgs(),
-                  TemplArgInfo->NumTemplateArgs, InstArgs, TemplateArgs))
-          return nullptr;
-      }
-      auto *Inst = cast<TemplateTypeParmDecl>(
-          FindInstantiatedDecl(TTP->getLocation(), TTP, TemplateArgs));
-      if (AttachTypeConstraint(
-              TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
-              TC->getNamedConcept(), &InstArgs, Inst,
-              TTP->isParameterPack()
-                  ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
-                      ->getEllipsisLoc()
-                  : SourceLocation()))
-        return nullptr;
-    }
-  }
-
   ParmVarDecl *NewParm = CheckParameter(Context.getTranslationUnitDecl(),
                                         OldParm->getInnerLocStart(),
                                         OldParm->getLocation(),
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 0e1d5fa77c693..2637b4cb6dcab 100755
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2525,34 +2525,28 @@ Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
   Inst->setAccess(AS_public);
   Inst->setImplicit(D->isImplicit());
   if (auto *TC = D->getTypeConstraint()) {
-    if (!D->isImplicit()) {
-      // Invented template parameter type constraints will be instantiated with
-      // the corresponding auto-typed parameter as it might reference other
-      // parameters.
-
-      // TODO: Concepts: do not instantiate the constraint (delayed constraint
-      // substitution)
-      const ASTTemplateArgumentListInfo *TemplArgInfo
-        = TC->getTemplateArgsAsWritten();
-      TemplateArgumentListInfo InstArgs;
-
-      if (TemplArgInfo) {
-        InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
-        InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
-        if (SemaRef.Subst(TemplArgInfo->getTemplateArgs(),
-                          TemplArgInfo->NumTemplateArgs,
-                          InstArgs, TemplateArgs))
-          return nullptr;
-      }
-      if (SemaRef.AttachTypeConstraint(
-              TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
-              TC->getNamedConcept(), &InstArgs, Inst,
-              D->isParameterPack()
-                  ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
-                      ->getEllipsisLoc()
-                  : SourceLocation()))
+    // TODO: Concepts: do not instantiate the constraint (delayed constraint
+    // substitution)
+    const ASTTemplateArgumentListInfo *TemplArgInfo
+      = TC->getTemplateArgsAsWritten();
+    TemplateArgumentListInfo InstArgs;
+
+    if (TemplArgInfo) {
+      InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
+      InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
+      if (SemaRef.Subst(TemplArgInfo->getTemplateArgs(),
+                        TemplArgInfo->NumTemplateArgs,
+                        InstArgs, TemplateArgs))
         return nullptr;
     }
+    if (SemaRef.AttachTypeConstraint(
+            TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
+            TC->getNamedConcept(), &InstArgs, Inst,
+            D->isParameterPack()
+                ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
+                    ->getEllipsisLoc()
+                : SourceLocation()))
+      return nullptr;
   }
   if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {
     TypeSourceInfo *InstantiatedDefaultArg =
diff --git a/clang/test/SemaTemplate/instantiate-abbreviated-template.cpp b/clang/test/SemaTemplate/instantiate-abbreviated-template.cpp
deleted file mode 100644
index a73b6ce3610fa..0000000000000
--- a/clang/test/SemaTemplate/instantiate-abbreviated-template.cpp
+++ /dev/null
@@ -1,29 +0,0 @@
-// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
-// expected-no-diagnostics
-
-template<typename...>
-concept C = true;
-
-template<typename T>
-struct S {
-    template<typename U>
-    static void foo1(U a, auto b);
-    static void foo2(T a, C<T> auto b);
-    static void foo3(T a, C<decltype(a)> auto b);
-    static void foo4(T a, C<decltype(a)> auto b, const C<decltype(b)> auto &&c);
-};
-
-using sf1 = decltype(S<int>::foo1(1, 2));
-using sf2 = decltype(S<int>::foo2(1, 2));
-using sf3 = decltype(S<int>::foo3(1, 2));
-using sf4 = decltype(S<int>::foo4(1, 2, 3));
-
-
-template<typename... T>
-struct G {
-    static void foo1(auto a, const C<decltype(a)> auto &&... b);
-    static void foo2(auto a, const C<decltype(a), T> auto &&... b);
-};
-
-using gf1 = decltype(G<int, char>::foo1('a', 1, 2, 3, 4));
-using gf2 = decltype(G<int, char>::foo2('a', 1, 2));