Fragment shader just copying values doesn't compile

Expected Behaviour

The following code snippet defines 3 fragment shaders, but the middle one does not get compiled / emit an entry point / generates a spv (with multibuilder true). Looks like it's somehow getting inlined / optimized away before monomorphization, so it's not picked up as an entry point?

#[spirv(fragment)]
pub fn fragment_works(v_color: Vec4, frag_color: &mut Vec4) {
  *frag_color = v_color +1.;
}

#[spirv(fragment)]
pub fn fragment_doesnt(v_color: Vec4, frag_color: &mut Vec4) {
  *frag_color = v_color;
}

/// causes a warning by rust-gpu about having to be inlined anyway
#[inline(never)]
#[spirv(fragment)]
pub fn fragment_works_again(v_color: Vec4, frag_color: &mut Vec4) {
  *frag_color = v_color;
}

Found while investigating an issue with hadronized on discord.

System Info

• cargo-gpu main
• I have no idea what rust-gpu version this is, cargo-gpu doesn't tell, apparently it's pointing to the git repo but it can't be main as the toolchains would mismatch.

Riprodurre i tre punti di ingresso dei fragment dall’issue usando cargo-gpu al commit main indicato, con multibuilder abilitato, e confrontarne la compilazione e l’output SPIR-V. Concentrarsi sul motivo per cui fragment_doesnt viene omesso mentre fragment_works_again viene mantenuto, nonostante entrambi copino v_color. Il lavoro è completato quando tutte e tre le funzioni compilano, emettono punti di ingresso e generano SPIR-V valido senza richiedere inline(never).