Emit diagnostics for device lambdas

[gevtushenko]

No description provided.

[gevtushenko]

run tests

[alliepiper]

We shouldn't use CUB headers outside of thrust/system/cuda/, as CUB is only a dependency when the CUDA backend is enabled.

Let's replicate the logic from CUB in Thrust's type_traits.h and use that instead.

[jrhemstad]

All the logic is in cuda::std::invoke_result isn't it? Can't we just use cuda::std::invoke_result directly?

[gevtushenko]

All the logic is in cuda::std::invoke_result isn't it? Can't we just use cuda::std::invoke_result directly?

Invoke result is C++17 feature. CUB wrapper switches to result of for previous dialects.

[jrhemstad]

Invoke result is C++17 feature. CUB wrapper switches to result of for previous dialects.

Can't we back port cuda::std::invoke_result_t to be available prior to C++17?

It's just a library feature, and we already have back ported many Standard Library features in libcu++, e.g., NVIDIA/libcudacxx#66

[alliepiper]

Can't we back port cuda::std::invoke_result_t to be available prior to C++17?

We'd need a libcu++ release by 8/15 to do this.

[gevtushenko]

run tests