The workaround option is now set to none by default. Use
```
matc -Wall
```
if you want to restore the previous behavior.
Current material workarounds:
- remove MergeReturnPass (except on Metal)
- remove SimplificationPass (except on Metal)
There are reason to believe these workarounds are no longer needed,
due to changes in spirv-opt.
It's possible that older devices might still need them.
These workaround affect *all* devices, this is why it is important
to disable them if not needed.
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