refactor: Avoid int64_t -> size_t -> int64_t conversion

Author: MarcoFalke

src/rpc/mempool.cpp

@@ -386,8 +386,8 @@ UniValue MempoolInfoToJSON(const CTxMemPool& pool)
     ret.pushKV("bytes", (int64_t)pool.GetTotalTxSize());
     ret.pushKV("usage", (int64_t)pool.DynamicMemoryUsage());
     ret.pushKV("total_fee", ValueFromAmount(pool.GetTotalFee()));
-    size_t maxmempool = gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
-    ret.pushKV("maxmempool", (int64_t) maxmempool);
+    int64_t maxmempool{gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000};
+    ret.pushKV("maxmempool", maxmempool);
     ret.pushKV("mempoolminfee", ValueFromAmount(std::max(pool.GetMinFee(maxmempool), ::minRelayTxFee).GetFeePerK()));
     ret.pushKV("minrelaytxfee", ValueFromAmount(::minRelayTxFee.GetFeePerK()));
     ret.pushKV("unbroadcastcount", uint64_t{pool.GetUnbroadcastTxs().size()});