gcc error - typedef is initialized (use decltype instead)

I'm compiling some C code, and I get the error

typedef 'A' is initialized (use decltype instead)

On one of my struct declarations. What could be causing this?

I am able to reproduce that with the simple program

typedef int A = 3;

typedef declares an alias to a type; it does not declare a variable. So if you want an instance of struct my_struct named A, you cannot also have typedef struct my_struct { ... } my_struct in the same declaration.