(witx
  (module $a (typename $u (union u8)))
)
(witx
  (module $a
    (typename $tag (enum (@witx tag u8) $c))
    (typename $u (union (@witx tag $tag) u8))
  )
)

(witx
  (module $a
    (typename $tag (enum $a $b))
    (typename $u (variant (@witx tag $tag) (case $a) (case $b u16)))
  )
)

(witx
  (module $a
    (typename $tag (enum $a $b))
    (typename $u (variant (@witx tag $tag) (case $a) (case $b)))
  )
)


(witx
 (module $a
  (typename $u
   (union
    u8
    u16
    u32
    u64
    s8
    s16
    s32
    s64
    f32
    f64
    (@witx usize)
    (@witx char8)
   )
  )
 )
)

(assert_invalid
  (witx (module $a (typename $u (union (@witx tag $tag) u8 u16))))
  "Unknown name `tag`"
)

(assert_invalid
  (witx
    (module $a
      (typename $tag string)
      (typename $u (union (@witx tag $tag) u8 u16))
    )
  )
  "Wrong kind of name `tag`: expected enum or builtin, got list"
)

(assert_invalid
  (witx
    (module $a
      (typename $tag (enum $c))
      (typename $u (variant (@witx tag $tag) (case $b u8)))
    )
  )
  "Invalid union field `b`: does not correspond to variant in tag `tag`"
)

(assert_invalid
  (witx
    (module $a
      (typename $tag (enum $c))
      (typename $u (union (@witx tag $tag) f32 u8))
    )
  )
  "Union expected 1 variants, found 2"
)

(assert_invalid
  (witx
    (module $a
      (typename $tag (enum $c $d))
      (typename $u (union (@witx tag $tag) f32))
    )
  )
  "Union expected 2 variants, found 1"
)

(witx
  (module $d1
    (typename $tag (enum $a $b))
    (typename $u (union (@witx tag $tag) u8 u16))
  )
)

(witx
  (module $d2
    (typename $tag (enum $a $b))
    (typename $u (variant (@witx tag $tag) (case $b u16) (case $a u8)))
  )
)

;; These two unions should be represented the same:
(assert_eq $d1 "u" $d2 "u")
(assert_eq $d2 "u" $d1 "u")

;; Tag order doesnt matter for validation, but does for equality
(witx
  (module $d3
    (typename $tag (enum $b $a))
    (typename $u (union (@witx tag $tag) u16 u8))
  )
)

(assert_ne $d3 "u" $d1 "u")