diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -4590,7 +4590,7 @@
 
 The argument ``T`` is optional and is ignored.
 This attribute may be used by analysis tools and has no effect on code
-generation.
+generation. A ``void`` argument means that the class can own any type.
 
 See Pointer_ for an example.
 }];
@@ -4616,7 +4616,7 @@
 
 The argument ``T`` is optional and is ignored.
 This attribute may be used by analysis tools and has no effect on code
-generation.
+generation. A ``void`` argument means that the pointer can point to any type.
 
 Example:
 When constructing an instance of a class annotated like this (a Pointer) from
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
@@ -2631,7 +2631,7 @@
 def err_attributes_are_not_compatible : Error<
   "%0 and %1 attributes are not compatible">;
 def err_attribute_invalid_argument : Error<
-  "%select{'void'|a reference type|an array type|a non-vector or "
+  "%select{a reference type|an array type|a non-vector or "
   "non-vectorizable scalar type}0 is an invalid argument to attribute %1">;
 def err_attribute_wrong_number_arguments : Error<
   "%0 attribute %plural{0:takes no arguments|1:takes one argument|"
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -2913,7 +2913,7 @@
   if (!ParmType->isExtVectorType() && !ParmType->isFloatingType() &&
       (ParmType->isBooleanType() ||
        !ParmType->isIntegralType(S.getASTContext()))) {
-    S.Diag(AL.getLoc(), diag::err_attribute_invalid_argument) << 3 << AL;
+    S.Diag(AL.getLoc(), diag::err_attribute_invalid_argument) << 2 << AL;
     return;
   }
 
@@ -4454,12 +4454,10 @@
     ParmType = S.GetTypeFromParser(AL.getTypeArg(), &DerefTypeLoc);
 
     unsigned SelectIdx = ~0U;
-    if (ParmType->isVoidType())
+    if (ParmType->isReferenceType())
       SelectIdx = 0;
-    else if (ParmType->isReferenceType())
-      SelectIdx = 1;
     else if (ParmType->isArrayType())
-      SelectIdx = 2;
+      SelectIdx = 1;
 
     if (SelectIdx != ~0U) {
       S.Diag(AL.getLoc(), diag::err_attribute_invalid_argument)
diff --git a/clang/test/SemaCXX/attr-gsl-owner-pointer.cpp b/clang/test/SemaCXX/attr-gsl-owner-pointer.cpp
--- a/clang/test/SemaCXX/attr-gsl-owner-pointer.cpp
+++ b/clang/test/SemaCXX/attr-gsl-owner-pointer.cpp
@@ -31,9 +31,11 @@
 // CHECK: OwnerAttr {{.*}} int
 
 class [[gsl::Owner(void)]] OwnerVoidDerefType{};
-// expected-error@-1 {{'void' is an invalid argument to attribute 'Owner'}}
+// CHECK: CXXRecordDecl {{.*}} OwnerVoidDerefType
+// CHECK: OwnerAttr {{.*}} void
 class [[gsl::Pointer(void)]] PointerVoidDerefType{};
-// expected-error@-1 {{'void' is an invalid argument to attribute 'Pointer'}}
+// CHECK: CXXRecordDecl {{.*}} PointerVoidDerefType
+// CHECK: PointerAttr {{.*}} void
 
 class [[gsl::Pointer(int)]] AddConflictLater{};
 // CHECK: CXXRecordDecl {{.*}} AddConflictLater