test cuda: <fmt/core.h> checks NVCC and CUDA

The header file checks 2 things.

* __NVCC__: if the compiler is from NVIDIA
* __CUDACC__: if the source code is CUDA(.cu) file

Since we can't sure all users prefer latest, Version for
`find_pacakge(CUDA)` is downgraded to 9.0.
This is the minimum version for C++14 in CUDA

include/fmt/core.h

@@ -132,6 +132,7 @@
 #    endif
 #  endif
 #endif
+
 // Workaround broken [[deprecated]] in the Intel compiler.
 #ifdef __INTEL_COMPILER
 #  define FMT_DEPRECATED_ALIAS
@@ -139,6 +140,13 @@
 #  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
 #endif
 
+// Workaround broken [[deprecated]] for the NVCC (CUDA with C++14)
+#if defined(__NVCC__) || defined(__CUDACC__)
+#  define FMT_DEPRECATED_ALIAS
+#else
+#  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
+#endif
+
 #ifndef FMT_BEGIN_NAMESPACE
 #  if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
       FMT_MSC_VER >= 1900

test/CMakeLists.txt

@@ -227,10 +227,10 @@ if (FMT_PEDANTIC AND NOT WIN32)
 endif ()
 
 #
-# Activate CUDA related tests (Optional)
-# if and only if we can find the CUDA in current CMake run.
+# Activate CUDA related tests if we can find CUDA from CMake. This is optional.
+# For version selection, see https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#cpp14-language-features
 #
-find_package(CUDA 9.2)
+find_package(CUDA 9.0)
 if(CUDA_FOUND)
   add_test(cuda-test ${CMAKE_CTEST_COMMAND}
     -C ${CMAKE_BUILD_TYPE}

test/cuda-test/cuda-cpp14.cu

@@ -24,9 +24,11 @@ static_assert(__cplusplus >= 201402L, "expect C++ 2014 for nvcc");
 // Since we don't know the actual case in this header, checking both macro
 // will prevent possible pitfalls ...
 //
-#if defined(__NVCC__) || defined(__CUDACC__)
-#  define FMT_DEPRECATED
-#endif
+// --- this check is moved into the <fmt/core.h> ---
+//
+// #if defined(__NVCC__) || defined(__CUDACC__)
+// #  define FMT_DEPRECATED // suppress [[deprecated]] attribute
+// #endif
 #include <fmt/core.h>
 
 #include <cuda.h>