The return value isn't used outside of tests, so I think it can be removed. If someone is interested in the size, they can just call .size().

auto size_before = orphanage.Size();
auto limit = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
auto n_evicted = WITH_LOCK(g_cs_orphans, return orphanage.LimitOrphans(limit));
Assert(size_before - n_evicted <= limit);
Assert(orphanage.Size() <= limit);

In most cases size_before - n_evicted == orphange.Size(), so we don't need the return value of LimitOrphans. But IMO it will not hurt to use the return value for an additional check. Actually I also think EraseForBlock can return nErased.

In most cases size_before - n_evicted == orphange.Size(), so we don't need the return value of LimitOrphans

Can you give an example where the equality wouldn't hold, assuming after the changes in this pull requests?

The equality wouldn't hold if n_evicted or n_expired is incremented but EraseTx fail to remove tx from m_orphanage. It seems this never happen since the txid passed to EraseTx is valid. So feel free to request change and I will make the function return void.

Yeah, I am thinking, either:

• the equality holds, in which case the return value is unused and redundant, also confuse the devs which is the "correct" way to get the size. Also, if the return value was used in the future, it can trivially be added back.
• the equality doesn't hold, in which case the return value is confusing, since it is wrong.

Regardless of which case holds, removing the return value is likely the correct "fix".