Bus as input in C MEX S-Function and array of structure as structure members

I want to build an sfunction with an input bus of type t_Struct2 which is defined like this :

typedef struct {

int a; int b; } t_Struct1;

typedef struct {

int c; t_Struct1 d[10]; } t_Struct2;

When I try to generate the code for the c-mex function and compile it the following error occurs :

error C2228: left of '.a' must have class/struct/union. Type is t_Struct1[10]

Is a structure containing a member of type array of structure allowed in this case ?

Both types t_Struct1 and t_Struct2 are defined in the same header.