diff --git a/include/Nazara/Core/Clock.hpp b/include/Nazara/Core/Clock.hpp
index b510137b7..ba39018fb 100644
--- a/include/Nazara/Core/Clock.hpp
+++ b/include/Nazara/Core/Clock.hpp
@@ -19,6 +19,7 @@ class NAZARA_API NzClock
 {
 	public:
 		NzClock(nzUInt64 startingValue = 0, bool paused = false);
+		NzClock(const NzClock& clock) = default;
 
 		float GetSeconds() const;
 		nzUInt64 GetMicroseconds() const;
@@ -30,6 +31,8 @@ class NAZARA_API NzClock
 		void Restart();
 		void Unpause();
 
+		NzClock& operator=(const NzClock& clock) = default;
+
 	private:
 		NazaraMutexAttrib(m_mutex, mutable)
 
diff --git a/include/Nazara/Core/Directory.hpp b/include/Nazara/Core/Directory.hpp
index 1a7ae5905..393914473 100644
--- a/include/Nazara/Core/Directory.hpp
+++ b/include/Nazara/Core/Directory.hpp
@@ -8,6 +8,7 @@
 #define NAZARA_DIRECTORY_HPP
 
 #include <Nazara/Prerequesites.hpp>
+#include <Nazara/Core/NonCopyable.hpp>
 #include <Nazara/Core/String.hpp>
 
 #if defined(NAZARA_PLATFORM_WINDOWS)
@@ -27,7 +28,7 @@
 
 class NzDirectoryImpl;
 
-class NAZARA_API NzDirectory
+class NAZARA_API NzDirectory : NzNonCopyable
 {
 	public:
 		NzDirectory();
diff --git a/src/Nazara/Core/ByteArray.cpp b/src/Nazara/Core/ByteArray.cpp
index 94903dd4d..4636b826e 100644
--- a/src/Nazara/Core/ByteArray.cpp
+++ b/src/Nazara/Core/ByteArray.cpp
@@ -404,11 +404,14 @@ nzUInt8 NzByteArray::operator[](unsigned int pos) const
 
 NzByteArray& NzByteArray::operator=(const NzByteArray& array)
 {
-	ReleaseArray();
+	if (this != &array)
+	{
+		ReleaseArray();
 
-	m_sharedArray = array.m_sharedArray;
-	if (m_sharedArray != &emptyArray)
-		m_sharedArray->refCount++;
+		m_sharedArray = array.m_sharedArray;
+		if (m_sharedArray != &emptyArray)
+			m_sharedArray->refCount++;
+	}
 
 	return *this;
 }
diff --git a/src/Nazara/Core/String.cpp b/src/Nazara/Core/String.cpp
index 54e5b3eb7..cac71d221 100644
--- a/src/Nazara/Core/String.cpp
+++ b/src/Nazara/Core/String.cpp
@@ -2785,35 +2785,19 @@ NzString& NzString::Set(const char* string, unsigned int length)
 
 NzString& NzString::Set(const std::string& string)
 {
-	if (string.size() > 0)
-	{
-		if (m_sharedString->capacity >= string.size())
-			EnsureOwnership(true);
-		else
-		{
-			ReleaseString();
-
-			m_sharedString = new SharedString;
-			m_sharedString->capacity = string.size();
-			m_sharedString->string = new char[string.size()+1];
-		}
-
-		m_sharedString->size = string.size();
-		std::memcpy(m_sharedString->string, string.c_str(), string.size()+1);
-	}
-	else
-		ReleaseString();
-
-	return *this;
+	return Set(string.data(), string.size());
 }
 
 NzString& NzString::Set(const NzString& string)
 {
-	ReleaseString();
+	if (this != &string)
+	{
+		ReleaseString();
 
-	m_sharedString = string.m_sharedString;
-	if (m_sharedString != &emptyString)
-		m_sharedString->refCount++;
+		m_sharedString = string.m_sharedString;
+		if (m_sharedString != &emptyString)
+			m_sharedString->refCount++;
+	}
 
 	return *this;
 }