diff --git a/source/graphics/tests/test_ShaderManager.h b/source/graphics/tests/test_ShaderManager.h
index 73f1236a82..1feef552e9 100644
--- a/source/graphics/tests/test_ShaderManager.h
+++ b/source/graphics/tests/test_ShaderManager.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2013 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -93,7 +93,7 @@ public:
 	{
 		CShaderUniforms uniforms1;
 		CShaderUniforms uniforms2;
-		TS_ASSERT(uniforms1 == uniforms1);
+		TS_ASSERT(uniforms1 == uniforms2);
 
 		uniforms1.Add("FOO", CVector4D(1.0f, 0.0f, 0.0f, 0.0f));
 
diff --git a/source/gui/GUIRenderer.cpp b/source/gui/GUIRenderer.cpp
index 8c1016c408..84ac5f4d57 100644
--- a/source/gui/GUIRenderer.cpp
+++ b/source/gui/GUIRenderer.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2013 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -50,7 +50,7 @@ DrawCalls::DrawCalls(const DrawCalls&)
 {
 }
 
-const DrawCalls& DrawCalls::operator=(const DrawCalls&)
+DrawCalls& DrawCalls::operator=(const DrawCalls&)
 {
 	return *this;
 }
diff --git a/source/gui/GUIRenderer.h b/source/gui/GUIRenderer.h
index bb228ec1bf..a99cc2e25f 100644
--- a/source/gui/GUIRenderer.h
+++ b/source/gui/GUIRenderer.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2013 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -69,7 +69,7 @@ namespace GUIRenderer
 		DrawCalls();
 		// Copy/assignment results in an empty list, not an actual copy
 		DrawCalls(const DrawCalls&);
-		const DrawCalls& operator=(const DrawCalls&);
+		DrawCalls& operator=(const DrawCalls&);
 	};
 }
 
diff --git a/source/ps/Overlay.cpp b/source/ps/Overlay.cpp
index dae01025a3..c9b2449f07 100644
--- a/source/ps/Overlay.cpp
+++ b/source/ps/Overlay.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2009 Wildfire Games.
+/* Copyright (C) 2013 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -103,12 +103,13 @@ CRect::CRect(const float l, const float t, const float r, const float b) :
 }
 
 // =
-void CRect::operator = (const CRect& a)
+CRect& CRect::operator = (const CRect& a)
 {
 	left = a.left;
 	top = a.top;
 	right = a.right;
 	bottom = a.bottom;
+	return *this;
 }
 
 // ==
@@ -296,10 +297,11 @@ CPos::CPos(const float &_x, const float &_y) : x(_x), y(_y)
 }
 
 // =
-void CPos::operator = (const CPos& a)
+CPos& CPos::operator = (const CPos& a)
 {
 	x = a.x;
 	y = a.y;
+	return *this;
 }
 
 // ==
@@ -397,10 +399,11 @@ CSize::CSize(const float &_cx, const float &_cy) : cx(_cx), cy(_cy)
 }
 
 // =
-void CSize::operator = (const CSize& a)
+CSize& CSize::operator = (const CSize& a)
 {
 	cx = a.cx;
 	cy = a.cy;
+	return *this;
 }
 
 // ==
diff --git a/source/ps/Overlay.h b/source/ps/Overlay.h
index d4ed860ea2..e0bb1929bb 100644
--- a/source/ps/Overlay.h
+++ b/source/ps/Overlay.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2009 Wildfire Games.
+/* Copyright (C) 2013 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -79,7 +79,7 @@ public:
 	CRect(const float l, const float t, const float r, const float b);
 
 	// Operators
-	void				operator =  (const CRect& a);
+	CRect&				operator =  (const CRect& a);
 	bool				operator == (const CRect& a) const;
 	bool				operator != (const CRect& a) const;
 	CRect				operator -	(void) const;
@@ -172,7 +172,7 @@ public:
 	CPos(const float &_x, const float &_y);
 
 	// Operators
-	void				operator =  (const CPos& a);
+	CPos&				operator =  (const CPos& a);
 	bool				operator == (const CPos& a) const;
 	bool				operator != (const CPos& a) const;
 	CPos				operator -	(void) const;
@@ -211,7 +211,7 @@ public:
 	CSize(const float &_cx, const float &_cy);
 
 	// Operators
-	void				operator =  (const CSize& a);
+	CSize&				operator =  (const CSize& a);
 	bool				operator == (const CSize& a) const;
 	bool				operator != (const CSize& a) const;
 	CSize				operator -	(void) const;