Can't compile wgsl shaders that use the "modf" function

[sadmac7000]

Bevy version

0.15.0

[Optional] Relevant system information

AdapterInfo { name: "AMD Radeon RX 6600 (RADV NAVI23)", vendor: 4098, device: 29695, device_type: DiscreteGpu, driver: "radv", driver_info: "Mesa 24.2.8", backend: Vulkan }

What you did

I tried to use the following shader:

#import bevy_pbr::forward_io::VertexOutput

@fragment
fn fragment(
    mesh: VertexOutput
) -> @location(0) vec4<f32> {
    let uv = mesh.uv * 40;
    let u_fract = modf(uv.x).fract;
    let v_fract = modf(uv.y).fract;
    let u = step(0.99, u_fract);
    let v = step(0.99, v_fract);
    return vec4(0.0, 0.0, 0.0, max(u, v));
}

What went wrong

2024-12-29T07:41:28.067671Z ERROR bevy_render::render_resource::pipeline_cache: failed to process shader:
error: failed to build a valid final module: Entry point fragment at Fragment is invalid
  ┌─ grid_material.wgsl:9:19
  │
9 │     let v_fract = modf(uv.y).fract;
  │                   ^^^^ naga::Expression [7]
  │
  = Expression [7] is invalid
  = Type resolution failed
  = Special type is not registered within the module

[JMS55]

Issue with naga oil - it's not handling special types between modules. Same as what happens with ray query types.