isPureData

static assert(  isPureData!int );
static assert(  isPureData!float );
static assert(  isPureData!creal );

static struct Vec { float x,y,z; }
static assert(  isPureData!Vec );

static struct Arr { int[3] data; }
static assert(  isPureData!Arr );

static struct Some { float f; Vec v; Arr a; }
static assert(  isPureData!Some );

static assert( !isPureData!string );

static struct Bad { int[] data; }
static assert( !isPureData!Bad );