Wrong type error when validating globals with gc proposal features

[ShinWonho]

In the GC proposal, it allows using previous global value as an initializer expression.

Therefore, following wasm module is a valid module in the GC proposal.

;; global.wat
(module (global i32 (i32.const 0)) (global i32 (global.get 0)))

I run the module with the reference interpreter in the gc proposal, and it passes the validation.

$ gc/interperter/wasm global.wat
// terminates normally

As the reference interpreter also includes function references and tail call proposals, I enable all of them and run wat2wasm, but it raises type error.

$ wabt/bin/wat2wasm --enable-function-references --enable-tail-call --enable-gc global.wat
global.wat:1:60: error: initializer expression can only reference an imported global
(module (global i32 (i32.const 0)) (global i32 (global.get 0)))
                                                           ^