Cannot take the address of complex expression

[kamphaus]

pcre_uchar s[] = "abcd";
pcre_uchar *a = &s[1];
pcre_uchar *b = &s[0];
is_eq(a + 2 - 1 - b, 2);

gives the go build errors:

cannot take the address of (*(*[1000000000]pcre_uchar)(unsafe.Pointer(uintptr(unsafe.Pointer(&(*(*[1000000000]pcre_uchar)(unsafe.Pointer(uintptr(unsafe.Pointer(&a[0])) + uintptr(int32(2)) * unsafe.Sizeof(a[0]))))[:][0])) - uintptr(int32(1)) * unsafe.Sizeof((*(*[1000000000]pcre_uchar)(unsafe.Pointer(uintptr(unsafe.Pointer(&a[0])) + uintptr(int32(2)) * unsafe.Sizeof(a[0]))))[:][0]))))[:]
cannot take the address of (*(*[1000000000]pcre_uchar)(unsafe.Pointer(uintptr(unsafe.Pointer(&(*(*[1000000000]pcre_uchar)(unsafe.Pointer(uintptr(unsafe.Pointer(&a[0])) + uintptr(int32(2)) * unsafe.Sizeof(a[0]))))[:][0])) - uintptr(int32(1)) * unsafe.Sizeof((*(*[1000000000]pcre_uchar)(unsafe.Pointer(uintptr(unsafe.Pointer(&a[0])) + uintptr(int32(2)) * unsafe.Sizeof(a[0]))))[:][0]))))[:]