diff --git a/include/libtorrent/alert_manager.hpp b/include/libtorrent/alert_manager.hpp
index 6aefdece5..587c42d39 100644
--- a/include/libtorrent/alert_manager.hpp
+++ b/include/libtorrent/alert_manager.hpp
@@ -57,7 +57,7 @@ namespace libtorrent {
 	class TORRENT_EXTRA_EXPORT alert_manager
 	{
 	public:
-		alert_manager(int queue_limit
+		explicit alert_manager(int queue_limit
 			, alert_category_t alert_mask = alert::error_notification);
 
 		alert_manager(alert_manager const&) = delete;
diff --git a/src/block_cache.cpp b/src/block_cache.cpp
index 3196f0315..185b5a4e0 100644
--- a/src/block_cache.cpp
+++ b/src/block_cache.cpp
@@ -322,8 +322,8 @@ cached_piece_entry::cached_piece_entry()
 cached_piece_entry::~cached_piece_entry()
 {
 	TORRENT_ASSERT(piece_refcount == 0);
-	TORRENT_ASSERT(jobs.size() == 0);
-	TORRENT_ASSERT(read_jobs.size() == 0);
+	TORRENT_ASSERT(jobs.empty());
+	TORRENT_ASSERT(read_jobs.empty());
 #if TORRENT_USE_ASSERTS
 	if (blocks)
 	{
@@ -766,7 +766,7 @@ cached_piece_entry* block_cache::add_dirty_block(disk_io_job* j)
 // (since these blocks now are part of the read cache) the refcounts of the
 // blocks are also decremented by this function. They are expected to have been
 // incremented by the caller.
-bool block_cache::blocks_flushed(cached_piece_entry* pe, int const* flushed, int num_flushed)
+bool block_cache::blocks_flushed(cached_piece_entry* pe, int const* flushed, int const num_flushed)
 {
 	TORRENT_PIECE_ASSERT(pe->in_use, pe);
 
@@ -883,7 +883,7 @@ bool block_cache::evict_piece(cached_piece_entry* pe, tailqueue<disk_io_job>& jo
 
 		// append will move the items from pe->jobs onto the end of jobs
 		jobs.append(pe->jobs);
-		TORRENT_ASSERT(pe->jobs.size() == 0);
+		TORRENT_ASSERT(pe->jobs.empty());
 
 		if (mode == allow_ghost
 			&& (pe->cache_state == cached_piece_entry::read_lru1_ghost
@@ -1005,7 +1005,7 @@ int block_cache::try_evict_blocks(int num, cached_piece_entry* ignore)
 		// to iterate over this linked list. Presumably because of the random
 		// access of memory. It would be nice if pieces with no evictable blocks
 		// weren't in this list
-		for (list_iterator<cached_piece_entry> i = lru_list[end]->iterate(); i.get() && num > 0;)
+		for (auto i = lru_list[end]->iterate(); i.get() && num > 0;)
 		{
 			cached_piece_entry* pe = i.get();
 			TORRENT_PIECE_ASSERT(pe->in_use, pe);
@@ -1077,7 +1077,7 @@ int block_cache::try_evict_blocks(int num, cached_piece_entry* ignore)
 	{
 		for (int pass = 0; pass < 2 && num > 0; ++pass)
 		{
-			for (list_iterator<cached_piece_entry> i = m_lru[cached_piece_entry::write_lru].iterate(); i.get() && num > 0;)
+			for (auto i = m_lru[cached_piece_entry::write_lru].iterate(); i.get() && num > 0;)
 			{
 				cached_piece_entry* pe = i.get();
 				TORRENT_PIECE_ASSERT(pe->in_use, pe);
@@ -1263,7 +1263,7 @@ void block_cache::insert_blocks(cached_piece_entry* pe, int block, span<iovec_t
 
 	TORRENT_ASSERT(pe);
 	TORRENT_ASSERT(pe->in_use);
-	TORRENT_PIECE_ASSERT(iov.size() > 0, pe);
+	TORRENT_PIECE_ASSERT(!iov.empty(), pe);
 
 	cache_hit(pe, j->d.io.offset / default_block_size, bool(j->flags & disk_interface::volatile_read));
 
@@ -1349,7 +1349,7 @@ bool block_cache::inc_block_refcount(cached_piece_entry* pe, int block, int reas
 	return true;
 }
 
-void block_cache::dec_block_refcount(cached_piece_entry* pe, int block, int reason)
+void block_cache::dec_block_refcount(cached_piece_entry* pe, int const block, int const reason)
 {
 	TORRENT_PIECE_ASSERT(pe->in_use, pe);
 	TORRENT_PIECE_ASSERT(block < pe->blocks_in_piece, pe);
@@ -1762,12 +1762,12 @@ cached_piece_entry* block_cache::find_piece(disk_io_job const* j)
 	return find_piece(j->storage.get(), j->piece);
 }
 
-cached_piece_entry* block_cache::find_piece(storage_interface* st, piece_index_t piece)
+cached_piece_entry* block_cache::find_piece(storage_interface* st, piece_index_t const piece)
 {
 	cached_piece_entry model;
 	model.storage = st->shared_from_this();
 	model.piece = piece;
-	auto i = m_pieces.find(model);
+	auto const i = m_pieces.find(model);
 	TORRENT_ASSERT(i == m_pieces.end() || (i->storage.get() == st && i->piece == piece));
 	if (i == m_pieces.end()) return nullptr;
 	TORRENT_PIECE_ASSERT(i->in_use, &*i);
diff --git a/src/bt_peer_connection.cpp b/src/bt_peer_connection.cpp
index 7307fd562..800de5d31 100644
--- a/src/bt_peer_connection.cpp
+++ b/src/bt_peer_connection.cpp
@@ -738,7 +738,7 @@ namespace {
 		std::memcpy(ptr, ih.data(), ih.size());
 		ptr += 20;
 
-		std::memcpy(ptr, &m_our_peer_id[0], 20);
+		std::memcpy(ptr, m_our_peer_id.data(), 20);
 		ptr += 20;
 
 #ifndef TORRENT_DISABLE_LOGGING
diff --git a/src/pe_crypto.cpp b/src/pe_crypto.cpp
index e55a4b800..46238fed4 100644
--- a/src/pe_crypto.cpp
+++ b/src/pe_crypto.cpp
@@ -308,7 +308,7 @@ namespace libtorrent {
 	{
 		span<span<char const>> empty;
 		if (!m_encrypt) return std::make_tuple(0, empty);
-		if (bufs.size() == 0) return std::make_tuple(0, empty);
+		if (bufs.empty()) return std::make_tuple(0, empty);
 
 		int bytes_processed = 0;
 		for (auto& buf : bufs)