test(overload): add test case overload_error2

unittest/negative/overload_error2.decaf

+class A
+{
+	void print ()
+	{
+		Print ( "A.print\n" );
+	}
+}
+
+class B extends A
+{
+	void print ()
+	{
+		Print ( "B.print\n" );
+	}
+}
+
+class C extends B
+{
+	void print ()
+	{
+		Print ( "C.print\n" );
+	}
+}
+
+class D extends B
+{
+	void print ()
+	{
+		Print ( "D.print\n" );
+	}
+}
+
+class F
+{
+	static void f ( class A a, class A b )
+	{
+		Print ( "F: A A\n" );
+	}
+
+	static void f ( class A a, class B b )
+	{
+		Print ( "F: A B\n" );
+	}
+}
+
+class G
+{
+	void f ( class A a, class A b )
+	{
+		Print ( "G: A A\n" );
+	}
+
+	void f ( class A a, class C b )
+	{
+		Print ( "G: A C\n" );
+	}
+
+	void f ( class A a, class B b )
+	{
+		Print ( "G: A B\n" );
+	}
+
+	void f ( class B a, class A b )
+	{
+		Print ( "G: B A\n" );
+	}
+
+	void f ( class C a, class B b )
+	{
+		Print ( "G: C B\n" );
+	}
+}
+
+class Main
+{
+	static void main ()
+	{
+		class A a;
+		a = new A ();
+		class B b;
+		b = new B ();
+		class C c;
+		c = new C ();
+		class D d;
+		d = new D ();
+
+		F.f ( a, a );
+		F.f ( a, b );
+		F.f ( a, c );
+		F.f ( b, a );
+		F.f ( b, b );
+		F.f ( b, c );
+		F.f ( c, a );
+		F.f ( c, b );
+		F.f ( c, c );
+
+		class G g;
+		g = new G ();
+		g.f ( a, a );
+		g.f ( a, b );
+		g.f ( a, c );
+		g.f ( a, d );
+		g.f ( b, a );
+		g.f ( b, b );
+		g.f ( b, c );
+		g.f ( b, d );
+		g.f ( c, a );
+		g.f ( c, b );
+		g.f ( c, c );
+		g.f ( c, d );
+		g.f ( d, a );
+		g.f ( d, b );
+		g.f ( d, c );
+		g.f ( d, d );
+	}
+}
\ No newline at end of file

unittest/negative/result/overload_error2.result

+*** Error at (104,5): call of overloaded f(class : B, class : B) is ambiguous, candidates are :
+        *** note  : candidate at (58,7) : void f(class : A, class : B)
+        *** note  : candidate at (63,7) : void f(class : B, class : A)
+*** Error at (105,5): call of overloaded f(class : B, class : C) is ambiguous, candidates are :
+        *** note  : candidate at (53,7) : void f(class : A, class : C)
+        *** note  : candidate at (63,7) : void f(class : B, class : A)
+*** Error at (106,5): call of overloaded f(class : B, class : D) is ambiguous, candidates are :
+        *** note  : candidate at (58,7) : void f(class : A, class : B)
+        *** note  : candidate at (63,7) : void f(class : B, class : A)
+*** Error at (109,5): call of overloaded f(class : C, class : C) is ambiguous, candidates are :
+        *** note  : candidate at (53,7) : void f(class : A, class : C)
+        *** note  : candidate at (68,7) : void f(class : C, class : B)
+*** Error at (112,5): call of overloaded f(class : D, class : B) is ambiguous, candidates are :
+        *** note  : candidate at (58,7) : void f(class : A, class : B)
+        *** note  : candidate at (63,7) : void f(class : B, class : A)
+*** Error at (113,5): call of overloaded f(class : D, class : C) is ambiguous, candidates are :
+        *** note  : candidate at (53,7) : void f(class : A, class : C)
+        *** note  : candidate at (63,7) : void f(class : B, class : A)
+*** Error at (114,5): call of overloaded f(class : D, class : D) is ambiguous, candidates are :
+        *** note  : candidate at (58,7) : void f(class : A, class : B)
+        *** note  : candidate at (63,7) : void f(class : B, class : A)