repro.rs

 let iad = pollster::block_on(rend3::create_iad(
        None,
        None,
        Some(RendererMode::CPUPowered),
    ))
    .unwrap();

    let vert = iad.device.create_shader_module(&ShaderModuleDescriptor {
        label: Some("vert"),
        source: ShaderSource::Wgsl(
            r#"
[[stage(vertex)]]
fn main() -> [[builtin(position)]] vec4<f32> {
    return vec4<f32>(0.0, 0.0, 0.0, 1.0);
}
"#
            .into(),
        ),
    });

    let frag = iad.device.create_shader_module(&ShaderModuleDescriptor {
        label: Some("frag"),
        source: ShaderSource::Wgsl(
            r#"
[[stage(fragment)]]
fn main() -> [[location(0)]] vec4<f32> {
    return vec4<f32>(0.0, 0.0, 0.0, 1.0);
}
"#
            .into(),
        ),
    });

    iad.device
        .create_render_pipeline(&RenderPipelineDescriptor {
            label: Some("test"),
            layout: None,
            vertex: VertexState {
                module: &vert,
                entry_point: "main",
                buffers: &[],
            },
            primitive: Default::default(),
            depth_stencil: None,
            multisample: Default::default(),
            fragment: Some(FragmentState {
                module: &frag,
                entry_point: "main",
                targets: &[ColorTargetState {
                    format: TARGET_FORMAT,
                    blend: None,
                    write_mask: ColorWrites::ALL,
                }],
            }),
        });