Packed Type

WasmGC introduces packed types, which are i8 and i16. They can only exist in array and struct field types. When taking them out of fields, it's required that using special *.get_s or *.get_u instructions.

Misuse of *.get

It's invalid to use *.get instructions to take out packed types.

(module
  (type (struct (field i8)))
  (func (param (ref 0)) (result i32)
    local.get 0
    struct.get 0 0))

Quick fixes are available for replacing *.get with *.get_s or *.get_u.

Misuse of *.get_s or *.get_u

It's invalid to use *.get_s or *.get_u instructions to take out normal value types.

(module
  (type (struct (field i32)))
  (func (param (ref 0)) (result i32)
    local.get 0
    struct.get_s 0 0)
  (func (param (ref 0)) (result i32)
    local.get 0
    struct.get_u 0 0))

Quick fixes are available for replacing *.get_s or *.get_u with *.get.