Random compilation errors on DistinguishUnitaries Kata

[anpaz]

Describe the bug

During our e2e and release builds, running some Katas like gives this error randomly:

CS0136 ((null):(null)): A local or parameter named '__arg1__' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter

To Reproduce

The error has been reported mainly on the notebooks in the DistinguishUnitaries Kata

[anpaz]

This has been narrowed down to microsoft/qsharp-compiler#1393

[cgranade]

Thanks for narrowing this down, @anpaz! Would you recommend mitigating on the IQ# side until microsoft/qsharp-compiler#1393 is resolved, then?

[anpaz]

Yes @cgranade. Just pushed #631 to make codegen sync.

[cgranade]

Apologies, posted right before I saw the notification for the matching PR!