by tonygarnockjones:

Before filing a bug, please check whether it has been fixed since
the latest release: run "hg pull -u" and retry what you did to
reproduce the problem.  Thanks.

What steps will reproduce the problem?

$ cat > problem.go <<EOF
package main

/*
typedef struct private_struct *private_struct_t;
private_struct_t m(void) { return (private_struct_t) 0; }
private_struct_t identity(private_struct_t arg) { return arg; }
*/
import "C"

func main() {
    s := C.m();
    s = C.identity(s);
}
EOF
$ cgo problem.go
$ tail -10 problem.cgo4.c 
void
_cgo_identity(void *v)
{
        struct {
                * p0;
                private_struct_t r;
        } *a = v;
        a->r = identity(a->p0);
}

What is the expected output? What do you see instead?

The "p0" member of the anonymous struct in _cgo_identity should be of type
"private_struct_t".

What is your $GOOS?  $GOARCH?

darwin amd64

Which revision are you using?  (hg identify)

2b13a45c7c91 tip

Please provide any additional information below.