The following assertion seems redundant. Is it a mistake? Two lines prior the same assertion is made, and the value being asserted doesn't appear to change in-between. However the next line asserts a condition on a different variable which differs by only one letter. Is the referenced line a duplicate assertion of `ret` and therefore redundant, or is it supposed to be `assert(rec)`?

https://github.com/bitcoin/bitcoin/blob/7275365c9bc7e7ebd6bbf7dcb251946aac44b5de/src/key.cpp#L247-L251
return 0;
    }
    privkey += 3;
    
    if (end - privkey < 2 || privkey[0] != 0x04u) {
        return 0;
    }
    ptrdiff_t oslen = privkey[1];
    privkey += 2;
    if (oslen > 32 || end - privkey < oslen) {
        return 0;
    }
    memcpy(out32 + (32 - oslen), privkey, oslen);
    if (!secp256k1_ec_seckey_verify(ctx, out32)) {
        memset(out32, 0, 32);
        return 0;
    }
    return 1;
}
/**
 * This serializes to a DER encoding of the ECPrivateKey type from section C.4 of SEC 1
 * <http://www.secg.org/sec1-v2.pdf>. The optional parameters and publicKey fields are
 * included.
 *
 * privkey must point to an output buffer of length at least CKey::PRIVATE_KEY_SIZE bytes.
 * privkeylen must initially be set to the size of the privkey buffer. Upon return it
 * will be set to the number of bytes used in the buffer.
 * key32 must point to a 32-byte raw private key.
 */
static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, bool compressed) {