diff --git a/include/libtorrent/torrent_peer.hpp b/include/libtorrent/torrent_peer.hpp
index cdd4f1a8e..7169aa2c7 100644
--- a/include/libtorrent/torrent_peer.hpp
+++ b/include/libtorrent/torrent_peer.hpp
@@ -52,8 +52,8 @@ namespace libtorrent
 	{
 		torrent_peer(std::uint16_t port, bool connectable, int src);
 
-		std::uint64_t total_download() const;
-		std::uint64_t total_upload() const;
+		std::int64_t total_download() const;
+		std::int64_t total_upload() const;
 
 		std::uint32_t rank(external_ip const& external, int external_port) const;
 
diff --git a/src/lazy_bdecode.cpp b/src/lazy_bdecode.cpp
index 2bd653c1c..3bed98003 100644
--- a/src/lazy_bdecode.cpp
+++ b/src/lazy_bdecode.cpp
@@ -230,9 +230,9 @@ namespace libtorrent
 		TORRENT_ASSERT(m_type == dict_t || m_type == list_t);
 		if (m_data.list == nullptr) return 0;
 		if (m_type == dict_t)
-			return m_data.dict[0].val.m_len;
+			return int(m_data.dict[0].val.m_len);
 		else
-			return m_data.list[0].m_len;
+			return int(m_data.list[0].m_len);
 	}
 
 	std::int64_t lazy_entry::int_value() const
@@ -255,14 +255,14 @@ namespace libtorrent
 		TORRENT_ASSERT(int(m_size) <= this->capacity());
 		if (m_data.dict == nullptr)
 		{
-			int capacity = lazy_entry_dict_init;
+			int const capacity = lazy_entry_dict_init;
 			m_data.dict = new (std::nothrow) lazy_dict_entry[capacity + 1];
 			if (m_data.dict == nullptr) return nullptr;
-			m_data.dict[0].val.m_len = capacity;
+			m_data.dict[0].val.m_len = std::uint32_t(capacity);
 		}
 		else if (int(m_size) == this->capacity())
 		{
-			int capacity = this->capacity() * lazy_entry_grow_factor / 100;
+			int const capacity = this->capacity() * lazy_entry_grow_factor / 100;
 			lazy_dict_entry* tmp = new (std::nothrow) lazy_dict_entry[capacity + 1];
 			if (tmp == nullptr) return nullptr;
 			std::memcpy(tmp, m_data.dict, sizeof(lazy_dict_entry) * (m_size + 1));
@@ -270,7 +270,7 @@ namespace libtorrent
 
 			delete[] m_data.dict;
 			m_data.dict = tmp;
-			m_data.dict[0].val.m_len = capacity;
+			m_data.dict[0].val.m_len = std::uint32_t(capacity);
 		}
 
 		TORRENT_ASSERT(int(m_size) < this->capacity());
@@ -303,9 +303,10 @@ namespace libtorrent
 	void lazy_entry::construct_string(char const* start, int const length)
 	{
 		TORRENT_ASSERT(m_type == none_t);
+		TORRENT_ASSERT(length >= 0);
 		m_type = string_t;
 		m_data.start = start;
-		m_size = length;
+		m_size = std::uint32_t(length);
 		m_begin = start - 1 - num_digits(length);
 		m_len = std::uint32_t(start - m_begin + length);
 	}
@@ -333,7 +334,8 @@ namespace libtorrent
 		TORRENT_ASSERT(m_type == dict_t);
 		TORRENT_ASSERT(i < int(m_size));
 		lazy_dict_entry const& e = m_data.dict[i + 1];
-		return std::make_pair(std::string(e.name, e.val.m_begin - e.name), &e.val);
+		TORRENT_ASSERT(e.val.m_begin >= e.name);
+		return std::make_pair(std::string(e.name, std::size_t(e.val.m_begin - e.name)), &e.val);
 	}
 
 	std::string lazy_entry::dict_find_string_value(char const* name) const
@@ -424,14 +426,14 @@ namespace libtorrent
 		TORRENT_ASSERT(int(m_size) <= this->capacity());
 		if (m_data.start == nullptr)
 		{
-			int capacity = lazy_entry_list_init;
+			int const capacity = lazy_entry_list_init;
 			m_data.list = new (std::nothrow) lazy_entry[capacity + 1];
 			if (m_data.list == nullptr) return nullptr;
-			m_data.list[0].m_len = capacity;
+			m_data.list[0].m_len = std::uint32_t(capacity);
 		}
 		else if (int(m_size) == this->capacity())
 		{
-			int capacity = this->capacity() * lazy_entry_grow_factor / 100;
+			int const capacity = this->capacity() * lazy_entry_grow_factor / 100;
 			lazy_entry* tmp = new (std::nothrow) lazy_entry[capacity + 1];
 			if (tmp == nullptr) return nullptr;
 			std::memcpy(tmp, m_data.list, sizeof(lazy_entry) * (m_size + 1));
@@ -439,7 +441,7 @@ namespace libtorrent
 
 			delete[] m_data.list;
 			m_data.list = tmp;
-			m_data.list[0].m_len = capacity;
+			m_data.list[0].m_len = std::uint32_t(capacity);
 		}
 
 		TORRENT_ASSERT(int(m_size) < this->capacity());
@@ -561,6 +563,7 @@ namespace libtorrent
 
 	void print_string(std::string& ret, char const* str, int const len, bool single_line)
 	{
+		TORRENT_ASSERT(len >= 0);
 		bool printable = true;
 		for (int i = 0; i < len; ++i)
 		{
@@ -579,7 +582,7 @@ namespace libtorrent
 				ret.append(str + len - 14, 14);
 			}
 			else
-				ret.append(str, len);
+				ret.append(str, std::size_t(len));
 			ret += "'";
 			return;
 		}
diff --git a/src/torrent_peer.cpp b/src/torrent_peer.cpp
index 09a92e4c7..4569ee542 100644
--- a/src/torrent_peer.cpp
+++ b/src/torrent_peer.cpp
@@ -85,10 +85,10 @@ namespace libtorrent
 				swap(e1, e2);
 			std::uint32_t p;
 #if defined BOOST_BIG_ENDIAN
-			p = e1.port() << 16;
+			p = std::uint32_t(e1.port() << 16);
 			p |= e2.port();
 #elif defined BOOST_LITTLE_ENDIAN
-			p = aux::host_to_network(e2.port()) << 16;
+			p = std::uint32_t(aux::host_to_network(e2.port()) << 16);
 			p |= aux::host_to_network(e1.port());
 #else
 #error unsupported endianness
@@ -141,7 +141,7 @@ namespace libtorrent
 		return ret;
 	}
 
-	torrent_peer::torrent_peer(std::uint16_t port_, bool conn, int src)
+	torrent_peer::torrent_peer(std::uint16_t port_, bool conn, int const src)
 		: prev_amount_upload(0)
 		, prev_amount_download(0)
 		, connection(nullptr)
@@ -156,7 +156,7 @@ namespace libtorrent
 		, seed(false)
 		, fast_reconnects(0)
 		, trust_points(0)
-		, source(src)
+		, source(aux::numeric_cast<std::uint8_t>(src))
 #if !defined(TORRENT_DISABLE_ENCRYPTION) && !defined(TORRENT_DISABLE_EXTENSIONS)
 		// assume no support in order to
 		// prefer opening non-encrypted
@@ -179,9 +179,7 @@ namespace libtorrent
 #if TORRENT_USE_ASSERTS
 		, in_use(false)
 #endif
-	{
-		TORRENT_ASSERT((src & 0xff) == src);
-	}
+	{}
 
 	std::uint32_t torrent_peer::rank(external_ip const& external, int external_port) const
 	{
@@ -204,7 +202,7 @@ namespace libtorrent
 	}
 #endif
 
-	std::uint64_t torrent_peer::total_download() const
+	std::int64_t torrent_peer::total_download() const
 	{
 		if (connection != nullptr)
 		{
@@ -213,11 +211,11 @@ namespace libtorrent
 		}
 		else
 		{
-			return std::uint64_t(prev_amount_download) << 10;
+			return std::int64_t(prev_amount_download) << 10;
 		}
 	}
 
-	std::uint64_t torrent_peer::total_upload() const
+	std::int64_t torrent_peer::total_upload() const
 	{
 		if (connection != nullptr)
 		{
@@ -226,13 +224,11 @@ namespace libtorrent
 		}
 		else
 		{
-			return std::uint64_t(prev_amount_upload) << 10;
+			return std::int64_t(prev_amount_upload) << 10;
 		}
 	}
 
-	ipv4_peer::ipv4_peer(
-		tcp::endpoint const& ep, bool c, int src
-	)
+	ipv4_peer::ipv4_peer(tcp::endpoint const& ep, bool c, int src)
 		: torrent_peer(ep.port(), c, src)
 		, addr(ep.address().to_v4())
 	{