src/test/ui/layout/issue-96158-scalarpair-payload-might-be-uninit.rs

   1 // normalize-stderr-test "pref: Align\([1-8] bytes\)" -> "pref: $$PREF_ALIGN"
   2 #![crate_type = "lib"]
   3 #![feature(rustc_attrs)]
   4
   5 use std::mem::MaybeUninit;
   6
   7 enum HasNiche {
   8     A,
   9     B,
  10     C,
  11 }
  12
  13 // This should result in ScalarPair(Initialized, Union),
  14 // since the u8 payload will be uninit for `None`.
  15 #[rustc_layout(debug)]
  16 pub enum MissingPayloadField { //~ ERROR: layout_of
  17     Some(u8),
  18     None
  19 }
  20
  21 // This should result in ScalarPair(Initialized, Initialized),
  22 // since the u8 field is present in all variants,
  23 // and hence will always be initialized.
  24 #[rustc_layout(debug)]
  25 pub enum CommonPayloadField { //~ ERROR: layout_of
  26     A(u8),
  27     B(u8),
  28 }
  29
  30 // This should result in ScalarPair(Initialized, Union),
  31 // since, though a u8-sized field is present in all variants, it might be uninit.
  32 #[rustc_layout(debug)]
  33 pub enum CommonPayloadFieldIsMaybeUninit { //~ ERROR: layout_of
  34     A(u8),
  35     B(MaybeUninit<u8>),
  36 }
  37
  38 // This should result in ScalarPair(Initialized, Union),
  39 // since only the niche field (used for the tag) is guaranteed to be initialized.
  40 #[rustc_layout(debug)]
  41 pub enum NicheFirst { //~ ERROR: layout_of
  42     A(HasNiche, u8),
  43     B,
  44     C
  45 }
  46
  47 // This should result in ScalarPair(Union, Initialized),
  48 // since only the niche field (used for the tag) is guaranteed to be initialized.
  49 #[rustc_layout(debug)]
  50 pub enum NicheSecond { //~ ERROR: layout_of
  51     A(u8, HasNiche),
  52     B,
  53     C,
  54 }