Complex numbers warning (float _ComplexKB: Unexpected type: 6)

Hi,
I have defined a struct in test.h file like this

struct Measurement_results
{
        float a;
        complex float b;
};

Now I use the struct in test.c file

struct Measurement_results myResult;
myResult.a=1.0;
myResult.b=1+I;

The code is compiling Ok,But I get this warring

float _ComplexKB: Unexpected type: 6

what's wrong or what's the correct way of doing it?