Why does the typedefed struct fail to compile with NVCC?

Question

typedef struct {
    long long int mem_0;
} Tuple1;

typedef struct {
    int tag;
    union {
        struct Tuple1 Union0Case0;
    } data;
} Union0;

C:/Users/Marko/Documents/Visual Studio 2015/Projects/Multi-armed Bandit Experiments/SpiralExample/bin/Release/cuda_kernels.cu(10): error: incomplete type is not allowed

The above does in fact compile on the GCC 5.3.0 compiler. When I change it to this, it works:

struct Tuple1 {
    long long int mem_0;
};

struct Union0 {
    int tag;
    union {
        struct Tuple1 Union0Case0;
    } data;
};

Answer 1

To summarize the comments into an answer so that this question falls off the unanswered queue for the CUDA tag.

This:

typedef struct {
    long long int mem_0;
} Tuple1;

defines a type containing an unnamed structure. There is no definition of struct Tuple1.

This, on the other hand, defines such a structure:

struct Tuple1 {
    long long int mem_0;
};

and this defines a type containing such a named structure:

typedef struct Tuple1 {
    long long int mem_0;
} Tuple1_t;

Any of the latter two would be compatible with your other code.