Don't return reference to temporary object in Debug output.

src/Math/Matrix.h

@@ -232,7 +232,7 @@ template<class T> class Matrix<T, 2> {
 #endif
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T, size_t size> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Matrix<T, size>& value) {
+template<class T, size_t size> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Matrix<T, size>& value) {
     debug.setFlag(Corrade::Utility::Debug::SpaceAfterEachValue, false);
     debug << "Matrix(";
     for(size_t row = 0; row != size; ++row) {

src/Math/Matrix3.h

@@ -59,7 +59,7 @@ template<class T> class Matrix3: public Matrix<T, 3> {
 };
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Matrix3<T>& value) {
+template<class T> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Matrix3<T>& value) {
     return debug << static_cast<const Magnum::Math::Matrix<T, 3>&>(value);
 }
 #endif

src/Math/Matrix4.h

@@ -162,7 +162,7 @@ template<class T> class Matrix4: public Matrix<T, 4> {
 };
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Matrix4<T>& value) {
+template<class T> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Matrix4<T>& value) {
     return debug << static_cast<const Magnum::Math::Matrix<T, 4>&>(value);
 }
 #endif

src/Math/Vector.h

@@ -178,7 +178,7 @@ template<class T, size_t size> class Vector {
 };
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T, size_t size> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector<T, size>& value) {
+template<class T, size_t size> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector<T, size>& value) {
     debug.setFlag(Corrade::Utility::Debug::SpaceAfterEachValue, false);
     debug << "Vector(";
     for(size_t i = 0; i != size; ++i) {

src/Math/Vector2.h

@@ -76,7 +76,7 @@ template<class T> class Vector2: public Vector<T, 2> {
 };
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector2<T>& value) {
+template<class T> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector2<T>& value) {
     return debug << static_cast<const Magnum::Math::Vector<T, 2>&>(value);
 }
 #endif

src/Math/Vector3.h

@@ -112,7 +112,7 @@ template<class T> class Vector3: public Vector<T, 3> {
 };
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector3<T>& value) {
+template<class T> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector3<T>& value) {
     return debug << static_cast<const Magnum::Math::Vector<T, 3>&>(value);
 }
 #endif

src/Math/Vector4.h

@@ -119,7 +119,7 @@ template<class T> class Vector4: public Vector<T, 4> {
 };
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-template<class T> Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector4<T>& value) {
+template<class T> Corrade::Utility::Debug operator<<(Corrade::Utility::Debug debug, const Magnum::Math::Vector4<T>& value) {
     return debug << static_cast<const Magnum::Math::Vector<T, 4>&>(value);
 }
 #endif