[exim] Why $domain variable expands to sender domain?

Hello Exim Users.

I want to do some address rewritting based on recipent domain,
but $domain expands to sender domain.

Below is my address rewrite section:

-------------------------------------------------------------------
LOCAL_DOMAINS = myhost.mydomain.tld : mydomain.tld : localhost
[...]
domainlist local_domains = LOCAL_DOMAINS

begin rewrite
*@+local_domains  "${if inlist {$domain}{LOCAL_DOMAINS} \
        {$local_part@$domain}\
      {${lookup{${local_part@${domain}}}lsearch{CONFDIR/email-addresses}{$value}fail}}}" Ffrs
-------------------------------------------------------------------
I test address with exim user@???,
but $domain expands to myhost.mydomain.tld.
Why $domain expands to sender domain?

-- kevin