Using alias for reference to anonymous structure results in error

My theory is that gcc has a bug. The following compiles in both clang and gcc:

using type = const struct {}&;

But now when I change it to an rvalue reference it compiles with clang but not with gcc:

using type = const struct {}&&;

// main.cpp:8:17: error: expected ';' after struct definition
//  typedef struct {}&& type;
//                  ^
// main.cpp:8:17: error: missing type-name in typedef-declaration
// main.cpp:8:22: error: expected constructor, destructor, or type conversion before ';' token
//  typedef const struct {}&& type;
//                                ^

It fails with the typedef version as well with the same error:

typedef const struct {}&& type;

Why does this fail to compile in gcc? Is this an issue with the standard or a bug?