I can confirm the error submitted by zetab, I can also say that it happens for C functions and not only for C++ classes (C functions that return char* are shown as returning char), and I have found another serious flaw with return types:
As one types a simple C program like this:
#include <stdio.h>
#include <stdlib.h>
int main()
{
printf(
}
Upon typing the opening bracket of the standard function 'printf', which fires the printf declaration hint, the hint will show the function as "__MINGW_NOTHROW printf(const char*, ...)" thus omitting the return type (int) and the other declarations (_CRTIMP, __cdecl). Tested with the latest nightly (from this thread) and MinGW GCC 4.6.1.