diff --git a/include/libtorrent/bdecode.hpp b/include/libtorrent/bdecode.hpp
index 8150ba7f0..dc13ddbbc 100644
--- a/include/libtorrent/bdecode.hpp
+++ b/include/libtorrent/bdecode.hpp
@@ -280,7 +280,7 @@ struct TORRENT_EXPORT bdecode_node
 	type_t type() const;
 
 	// returns true if type() != none_t.
-	operator bool() const;
+	explicit operator bool() const;
 
 	// return a non-owning reference to this node. This is useful to refer to
 	// the root node without copying it in assignments.
diff --git a/include/libtorrent/copy_ptr.hpp b/include/libtorrent/copy_ptr.hpp
index 73c0d2e2b..7aa9903e6 100644
--- a/include/libtorrent/copy_ptr.hpp
+++ b/include/libtorrent/copy_ptr.hpp
@@ -59,7 +59,7 @@ namespace libtorrent
 			m_ptr = p.m_ptr;
 			p.m_ptr = tmp;
 		}
-		operator bool() const { return m_ptr != 0; }
+		explicit operator bool() const { return m_ptr != 0; }
 		~copy_ptr() { delete m_ptr; }
 	private:
 		T* m_ptr;
diff --git a/include/libtorrent/error_code.hpp b/include/libtorrent/error_code.hpp
index 8ff7af16c..bd3a3e248 100644
--- a/include/libtorrent/error_code.hpp
+++ b/include/libtorrent/error_code.hpp
@@ -502,7 +502,7 @@ namespace libtorrent
 		storage_error(): file(-1), operation(0) {}
 		explicit storage_error(error_code e): ec(e), file(-1), operation(0) {}
 
-		operator bool() const { return ec.value() != 0; }
+		explicit operator bool() const { return ec.value() != 0; }
 
 		// the error that occurred
 		error_code ec;
diff --git a/include/libtorrent/file.hpp b/include/libtorrent/file.hpp
index 7cab161f7..9a37d4561 100644
--- a/include/libtorrent/file.hpp
+++ b/include/libtorrent/file.hpp
@@ -219,7 +219,7 @@ namespace libtorrent
 		file const& operator*() const;
 		file* get();
 		file const* get() const;
-		operator bool() const;
+		explicit operator bool() const;
 		file_handle& reset(file* f = nullptr);
 
 		char stack[2048];
diff --git a/src/http_tracker_connection.cpp b/src/http_tracker_connection.cpp
index 46f2ec68c..a8c921de5 100644
--- a/src/http_tracker_connection.cpp
+++ b/src/http_tracker_connection.cpp
@@ -394,7 +394,7 @@ namespace libtorrent
 
 		// extract ip
 		i = info.dict_find_string("ip");
-		if (i == 0)
+		if (!i)
 		{
 			ec = errors::invalid_tracker_response;
 			return false;
@@ -403,7 +403,7 @@ namespace libtorrent
 
 		// extract port
 		i = info.dict_find_int("port");
-		if (i == 0)
+		if (!i)
 		{
 			ec = errors::invalid_tracker_response;
 			return false;
diff --git a/src/kademlia/item.cpp b/src/kademlia/item.cpp
index 429c8979c..ed70b6843 100644
--- a/src/kademlia/item.cpp
+++ b/src/kademlia/item.cpp
@@ -140,10 +140,12 @@ item::item(entry v)
 {}
 
 item::item(bdecode_node const& v)
-	: m_value(std::move(v))
-	, m_seq(0)
+	: m_seq(0)
 	, m_mutable(false)
-{}
+{
+	// TODO: implement ctor for entry from bdecode_node?
+	m_value = v;
+}
 
 item::item(entry v, span<char const> salt
 	, sequence_number const seq, public_key const& pk, secret_key const& sk)
diff --git a/src/kademlia/msg.cpp b/src/kademlia/msg.cpp
index 3affaf6ea..ed476ec67 100644
--- a/src/kademlia/msg.cpp
+++ b/src/kademlia/msg.cpp
@@ -73,7 +73,7 @@ bool verify_message_impl(bdecode_node const& message, span<key_desc_t const> des
 		// none_t means any type
 		if (ret[i] && ret[i].type() != k.type && k.type != bdecode_node::none_t)
 			ret[i].clear();
-		if (ret[i] == 0 && (k.flags & key_desc_t::optional) == 0)
+		if (!ret[i] && (k.flags & key_desc_t::optional) == 0)
 		{
 			// the key was not found, and it's not an optional key
 			std::snprintf(error.data(), error.size(), "missing '%s' key", k.name);
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index 9a8e4008a..aa0e433e2 100644
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -1336,7 +1336,7 @@ namespace libtorrent
 		}
 
 		bdecode_node info = torrent_file.dict_find_dict("info");
-		if (info == 0)
+		if (!info)
 		{
 			bdecode_node link = torrent_file.dict_find_string("magnet-uri");
 			if (link)
diff --git a/src/ut_pex.cpp b/src/ut_pex.cpp
index 58f63e3b1..d2b1fd0b6 100644
--- a/src/ut_pex.cpp
+++ b/src/ut_pex.cpp
@@ -360,7 +360,7 @@ namespace libtorrent { namespace
 #ifndef TORRENT_DISABLE_LOGGING
 			if (p6) num_dropped += p6.string_length() / 18;
 #endif
-			if (p6 != 0 && p6.type() == bdecode_node::string_t)
+			if (p6.type() == bdecode_node::string_t)
 			{
 				int const num_peers = p6.string_length() / 18;
 				char const* in = p6.string_ptr();
@@ -379,9 +379,7 @@ namespace libtorrent { namespace
 			if (p6) num_added += p6.string_length() / 18;
 #endif
 			bdecode_node p6f = pex_msg.dict_find("added6.f");
-			if (p6 != 0
-				&& p6f != 0
-				&& p6.type() == bdecode_node::string_t
+			if (p6.type() == bdecode_node::string_t
 				&& p6f.type() == bdecode_node::string_t
 				&& p6f.string_length() == p6.string_length() / 18)
 			{
diff --git a/test/test_magnet.cpp b/test/test_magnet.cpp
index c6093819a..59fe45326 100644
--- a/test/test_magnet.cpp
+++ b/test/test_magnet.cpp
@@ -199,8 +199,8 @@ TORRENT_TEST(magnet)
 	std::printf("session_state\n%s\n", print_entry(session_state2).c_str());
 
 	// make sure settings that haven't been changed from their defaults are not saved
-	TEST_CHECK(session_state2.dict_find("settings")
-		.dict_find("optimistic_disk_retry") == 0);
+	TEST_CHECK(!session_state2.dict_find("settings")
+		.dict_find("optimistic_disk_retry"));
 
 	s->load_state(session_state2);