unhelpful diagnostic from naga regarding missing &

[crowlKats]

wgpu version 24.0.0

While working on the reworked webgpu bindings for Deno, I attempted to run a test, which is a 1-1 copy of hello-compute but written in javascript.

So using this shader, I am getting this diagnostic:

Device::create_shader_module error: 
Shader validation error: 
   ┌─ :20:36
   │
20 │     let array_length = arrayLength(input);
   │                                    ^^^^^ naga::Expression [4]


error: GPUValidationError: 
Shader validation error: 
   ┌─ :20:36
   │
20 │     let array_length = arrayLength(input);
   │                                    ^^^^^ naga::Expression [4]

: Entry point doubleMe at Compute is invalid: Expression [4] is invalid: Loading of [3] can't be done

Apparently, thanks to @teoxoy the solution is to do arrayLength(&input). The diagnostic is not very helpful here.
Also unsure why this is happening, since the wgpu repo itself is using the shader as-is without this change, yet the example works fine.

[sagudev]

Also unsure why this is happening, since the wgpu repo itself is using the shader as-is without this change, yet the example works fine.

This example was introduced in 7fccb6b so it is not present in v24, but I tested it on trunk and it does not work (run via naga-cli). Is hello compute even tested in CI? cc @cwfitzgerald

[sagudev]

chromium reports this error:

Error while parsing WGSL: :20:24 error: no matching call to 'arrayLength(array<f32>)'

2 candidate functions:
 • 'arrayLength(ptr<storage, array<T>, R>  ✗ ) -> u32' where:
      ✗  'R' is 'read'
 • 'arrayLength(ptr<storage, array<T>, W>  ✗ ) -> u32' where:
      ✗  'W' is 'write' or 'read_write'

    let array_length = arrayLength(input);
                       ^^^^^^^^^^^^^^^^^^


 - While validating [ShaderModuleDescriptor]
 - While calling [Device].CreateShaderModule([ShaderModuleDescriptor]).

[cwfitzgerald]

Oh my goodness, did I manage to write a whole example and never acutely run it? I think I was so focused on ensuring it built when extracted from the repo I just... never ran it.

Correct that example is only ever built in CI as it's completely separate from our normal testing stack.

Very sorry @crowlKats I'll get on this right away