Compiling unicode problem in MSVC with CUDA10.1

Because of this is my first posting, I do not know how to post. Please let me know, if I need to add more information.
When I compiled unicode variable, I have gotten an error. It depends on the function order.

----- CudaErrorCode.cu compile error ----------
typedef struct
{
float θmax;
}stPath;

float Equation80a(stPath* path)
{
float θmax = 1;
return θmax;
}

void UnicodeTestMain(stPath* path)
{
path->θmax = (float)1;
}
1>Compiling CUDA source file CudaErrorCode.cu…
1>
1>C:\project\ASMT\source\FunctionTest>“C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\bin\nvcc.exe” -gencode=arch=compute_70,code=“sm_70,compute_70” --use-local-env -ccbin “C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.23.28105\bin\HostX86\x64” -x cu -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\include" -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\include" -G --keep-dir x64\Debug -maxrregcount=0 --machine 64 --compile -cudart static -g -DWIN32 -DWIN64 -D_DEBUG -D_CONSOLE -D_MBCS -Xcompiler "/EHsc /W3 /nologo /Od /Fdx64\Debug\vc142.pdb /FS /Zi /RTC1 /MDd " -o x64\Debug\CudaErrorCode.cu.obj “C:\project\ASMT\source\FunctionTest\CudaErrorCode.cu”
1>C:/project/ASMT/source/FunctionTest/CudaErrorCode.cu(16): error : class “stPath” has no member “\u03b8max”
1>
1>1 error detected in the compilation of “C:/Users/PC01/AppData/Local/Temp/tmpxft_000026fc_00000000-7_CudaErrorCode.cpp1.ii”.

Only change the function order. I can compile without error as fellow:
What am I missing?

typedef struct
{
float θmax;
}stPath;

void UnicodeTestMain(stPath* path)
{
path->θmax = (float)1;
}

float Equation80a(stPath* path)
{
float θmax = 1;
return θmax;
}

1>Compiling CUDA source file CudaErrorCode.cu…
1>
1>C:\project\ASMT\source\FunctionTest>“C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\bin\nvcc.exe” -gencode=arch=compute_70,code=“sm_70,compute_70” --use-local-env -ccbin “C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.23.28105\bin\HostX86\x64” -x cu -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\include" -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\include" -G --keep-dir x64\Debug -maxrregcount=0 --machine 64 --compile -cudart static -g -DWIN32 -DWIN64 -D_DEBUG -D_CONSOLE -D_MBCS -Xcompiler "/EHsc /W3 /nologo /Od /Fdx64\Debug\vc142.pdb /FS /Zi /RTC1 /MDd " -o x64\Debug\CudaErrorCode.cu.obj “C:\project\ASMT\source\FunctionTest\CudaErrorCode.cu”
1>CudaErrorCode.cu