[msl-out] Shadowed variables are not allowed and so need to be renamed

[superdump]

It seems in wgsl that shadowing of variables is allowed, something like:

let a: u8 = 1;
let a: f32 = 1.0;

This works fine when running with the Vulkan backend, but metal does not support this shadowing of variables and so the variables will need to be renamed.

[munrocket]

This is legal operation in WGSL?

[kvark]

No, it's not legal. Closing as dupe of #1044

[kvark]

I'm surprised MSL outputs this, actually. It uses the Namer to assign unique names 🤔
So may be a bug in msl-out.

[teoxoy]

The msl output is correct (no duplicates) as of current master. I tried to reproduce the issue with all released versions of naga without success.

@superdump do you still have this issue? There might be something else that's not working.

[teoxoy]

Let's close this for now, feel free to reopen if the issue is still present.