One suggestion

Hello.

I think it would be better if the compiler gives a specific runtime error message for using a stream identifier in kernel or API call which is not created yet.

In my version (15.10), compiler just gives segmentation fault without any useful information.

That might be hard. Depending on where the stream is declared, it could be initialized to zero, or contain garbage, which may look like a valid stream value. The PGI runtime doesn’t keep a list of valid streams, and I’m not sure the underlying CUDA does either. I’ll open an RFE and see what our engineers think.