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
@@ -1749,30 +1749,79 @@
 
 // FIXME: size expression and attribute locations (or keyword if we
 // ever fully support altivec syntax).
-class VectorTypeLoc : public InheritingConcreteTypeLoc<TypeSpecTypeLoc,
-                                                       VectorTypeLoc,
-                                                       VectorType> {
+struct VectorTypeLocInfo {
+  SourceLocation NameLoc;
+};
+
+class VectorTypeLoc : public ConcreteTypeLoc<UnqualTypeLoc, VectorTypeLoc,
+                                             VectorType, VectorTypeLocInfo> {
+public:
+  SourceLocation getNameLoc() const { return this->getLocalData()->NameLoc; }
+
+  void setNameLoc(SourceLocation Loc) { this->getLocalData()->NameLoc = Loc; }
+
+  SourceRange getLocalSourceRange() const {
+    return SourceRange(getNameLoc(), getNameLoc());
+  }
+
+  void initializeLocal(ASTContext &Context, SourceLocation Loc) {
+    setNameLoc(Loc);
+  }
+
+  TypeLoc getElementLoc() const { return getInnerTypeLoc(); }
+
+  QualType getInnerType() const { return this->getTypePtr()->getElementType(); }
 };
 
 // FIXME: size expression and attribute locations (or keyword if we
 // ever fully support altivec syntax).
 class DependentVectorTypeLoc
-    : public InheritingConcreteTypeLoc<TypeSpecTypeLoc,
-                                       DependentVectorTypeLoc,
-                                       DependentVectorType> {};
+    : public ConcreteTypeLoc<UnqualTypeLoc, DependentVectorTypeLoc,
+                             DependentVectorType, VectorTypeLocInfo> {
+public:
+  SourceLocation getNameLoc() const { return this->getLocalData()->NameLoc; }
 
-// FIXME: size expression and attribute locations.
-class ExtVectorTypeLoc : public InheritingConcreteTypeLoc<VectorTypeLoc,
-                                                          ExtVectorTypeLoc,
-                                                          ExtVectorType> {
+  void setNameLoc(SourceLocation Loc) { this->getLocalData()->NameLoc = Loc; }
+
+  SourceRange getLocalSourceRange() const {
+    return SourceRange(getNameLoc(), getNameLoc());
+  }
+
+  void initializeLocal(ASTContext &Context, SourceLocation Loc) {
+    setNameLoc(Loc);
+  }
+
+  TypeLoc getElementLoc() const { return getInnerTypeLoc(); }
+
+  QualType getInnerType() const { return this->getTypePtr()->getElementType(); }
 };
 
+// FIXME: size expression and attribute locations.
+class ExtVectorTypeLoc
+    : public InheritingConcreteTypeLoc<VectorTypeLoc, ExtVectorTypeLoc,
+                                       ExtVectorType> {};
+
 // FIXME: attribute locations.
 // For some reason, this isn't a subtype of VectorType.
-class DependentSizedExtVectorTypeLoc :
-    public InheritingConcreteTypeLoc<TypeSpecTypeLoc,
-                                     DependentSizedExtVectorTypeLoc,
-                                     DependentSizedExtVectorType> {
+class DependentSizedExtVectorTypeLoc
+    : public ConcreteTypeLoc<UnqualTypeLoc, DependentSizedExtVectorTypeLoc,
+                             DependentSizedExtVectorType, VectorTypeLocInfo> {
+public:
+  SourceLocation getNameLoc() const { return this->getLocalData()->NameLoc; }
+
+  void setNameLoc(SourceLocation Loc) { this->getLocalData()->NameLoc = Loc; }
+
+  SourceRange getLocalSourceRange() const {
+    return SourceRange(getNameLoc(), getNameLoc());
+  }
+
+  void initializeLocal(ASTContext &Context, SourceLocation Loc) {
+    setNameLoc(Loc);
+  }
+
+  TypeLoc getElementLoc() const { return getInnerTypeLoc(); }
+
+  QualType getInnerType() const { return this->getTypePtr()->getElementType(); }
 };
 
 struct MatrixTypeLocInfo {
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
@@ -6135,6 +6135,17 @@
     void VisitMacroQualifiedTypeLoc(MacroQualifiedTypeLoc TL) {
       TL.setExpansionLoc(Chunk.Loc);
     }
+    void VisitVectorTypeLoc(VectorTypeLoc TL) { TL.setNameLoc(Chunk.Loc); }
+    void VisitDependentVectorTypeLoc(DependentVectorTypeLoc TL) {
+      TL.setNameLoc(Chunk.Loc);
+    }
+    void VisitExtVectorTypeLoc(ExtVectorTypeLoc TL) {
+      TL.setNameLoc(Chunk.Loc);
+    }
+    void
+    VisitDependentSizedExtVectorTypeLoc(DependentSizedExtVectorTypeLoc TL) {
+      TL.setNameLoc(Chunk.Loc);
+    }
 
     void VisitTypeLoc(TypeLoc TL) {
       llvm_unreachable("unsupported TypeLoc kind in declarator!");
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
@@ -5178,7 +5178,7 @@
 QualType TreeTransform<Derived>::TransformDependentVectorType(
     TypeLocBuilder &TLB, DependentVectorTypeLoc TL) {
   const DependentVectorType *T = TL.getTypePtr();
-  QualType ElementType = getDerived().TransformType(T->getElementType());
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
   if (ElementType.isNull())
     return QualType();
 
@@ -5219,7 +5219,7 @@
   const DependentSizedExtVectorType *T = TL.getTypePtr();
 
   // FIXME: ext vector locs should be nested
-  QualType ElementType = getDerived().TransformType(T->getElementType());
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
   if (ElementType.isNull())
     return QualType();
 
@@ -5386,7 +5386,7 @@
 QualType TreeTransform<Derived>::TransformVectorType(TypeLocBuilder &TLB,
                                                      VectorTypeLoc TL) {
   const VectorType *T = TL.getTypePtr();
-  QualType ElementType = getDerived().TransformType(T->getElementType());
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
   if (ElementType.isNull())
     return QualType();
 
@@ -5409,7 +5409,7 @@
 QualType TreeTransform<Derived>::TransformExtVectorType(TypeLocBuilder &TLB,
                                                         ExtVectorTypeLoc TL) {
   const VectorType *T = TL.getTypePtr();
-  QualType ElementType = getDerived().TransformType(T->getElementType());
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
   if (ElementType.isNull())
     return QualType();
 
diff --git a/clang/test/SemaCXX/vector.cpp b/clang/test/SemaCXX/vector.cpp
--- a/clang/test/SemaCXX/vector.cpp
+++ b/clang/test/SemaCXX/vector.cpp
@@ -513,3 +513,20 @@
 }
 
 } // namespace PR45780
+
+namespace PR48540 {
+// The below used to cause an OOM error, or an assert, make sure it is still
+//  valid.
+int (__attribute__((vector_size(16))) a);
+
+template <typename T, int I>
+struct S {
+  T (__attribute__((vector_size(16))) a);
+  int (__attribute__((vector_size(I))) b);
+  T (__attribute__((vector_size(I))) c);
+};
+
+void use() {
+  S<int, 16> s;
+}
+} // namespace PR48540