[Migrated] ZST's in structs cause invalid pointer casts

Issue automatically imported from old repo: https://github.com/EmbarkStudios/rust-gpu/issues/1037
Old labels: t: bug,s: qptr may fix
Originally creatd by TrueDoctor on 2023-04-18T16:53:55Z

Expected Behaviour

The code should compile

Example & Steps To Reproduce

code:

 #[spirv(fragment)] 
 pub fn main(x: (usize, ())) {
    drop(&x.1); 
 }

result:

error: Cannot cast between pointer types
  --> examples/shaders/simplest-shader/src/lib.rs:44:55
   |
44 | #[spirv(fragment)] pub fn main(x: (usize, ())) { drop(&x.1); }
   |                                                       ^^^^
   |
   = note: from: *u32
   = note: to: *u8

error: Cannot offset a pointer to an arbitrary element
  --> examples/shaders/simplest-shader/src/lib.rs:44:55
   |
44 | #[spirv(fragment)] pub fn main(x: (usize, ())) { drop(&x.1); }
   |                                                       ^^^^

error: Cannot cast between pointer types
  --> examples/shaders/simplest-shader/src/lib.rs:44:50
   |
44 | #[spirv(fragment)] pub fn main(x: (usize, ())) { drop(&x.1); }
   |                                                  ^^^^^^^^^^
   |
   = note: from: *u8
   = note: to: *struct () {  }

System Info

• Rust: [e.g. 1.49.0-nightly (1eaadebb3 2020-10-21)]
• OS: linux 6.2.9-arch1-1
• GPU: Intel Iris Plus Graphics G7

Commencez par le reproducteur dans examples/shaders/simplest-shader/src/lib.rs, en particulier la fonction #[spirv(fragment)] et la référence à x.1. Exécutez l’exemple et examinez les erreurs de conversion de pointeur et de décalage arbitraire. C’est terminé lorsque cette structure d’apparence valide contenant un champ de tuple de taille nulle se compile sans ces erreurs.