test/tint/shader_io/fragment_output_locations.wgsl

@fragment
fn main0() -> @location(0) i32 {
  return 1;
}

@fragment
fn main1() -> @location(1) u32 {
  return 1u;
}

@fragment
fn main2() -> @location(2) f32 {
  return 1.0;
}

@fragment
fn main3() -> @location(3) vec4<f32> {
  return vec4<f32>(1.0, 2.0, 3.0, 4.0);
}