C#: Add viable callable testcases for regular and checked operators.

Author: michaelnebel

csharp/ql/test/library-tests/dispatch/CallGraph.expected

@@ -238,3 +238,7 @@
 | ViableCallable.cs:458:10:458:14 | M5<> | ViableCallable.cs:444:23:444:27 | M2<> |
 | ViableCallable.cs:475:10:475:12 | Run | ViableCallable.cs:468:10:468:11 | M2 |
 | ViableCallable.cs:475:10:475:12 | Run | ViableCallable.cs:473:17:473:18 | M1 |
+| ViableCallable.cs:492:10:492:12 | Run | ViableCallable.cs:487:32:487:32 | + |
+| ViableCallable.cs:492:10:492:12 | Run | ViableCallable.cs:488:40:488:40 | checked + |
+| ViableCallable.cs:492:10:492:12 | Run | ViableCallable.cs:489:28:489:35 | explicit conversion |
+| ViableCallable.cs:492:10:492:12 | Run | ViableCallable.cs:490:28:490:35 | checked explicit conversion |

csharp/ql/test/library-tests/dispatch/GetADynamicTarget.expected

@@ -471,3 +471,7 @@
 | ViableCallable.cs:461:9:461:30 | call to method M2<T> | C17.M2<T>(Func<T>) |
 | ViableCallable.cs:478:9:478:14 | call to method M1 | C18.M1() |
 | ViableCallable.cs:481:9:481:14 | call to method M2 | I2.M2() |
+| ViableCallable.cs:495:18:495:22 | call to operator + | C19.+(C19, C19) |
+| ViableCallable.cs:498:26:498:30 | call to operator checked + | C19.checked +(C19, C19) |
+| ViableCallable.cs:501:18:501:23 | call to operator explicit conversion | C19.explicit conversion(C19) |
+| ViableCallable.cs:504:26:504:31 | call to operator checked explicit conversion | C19.checked explicit conversion(C19) |

csharp/ql/test/library-tests/dispatch/ViableCallable.cs

@@ -480,4 +480,27 @@ void Run(I2 i)
         // Viable callables: I2.M2()
         i.M2();
     }
+}
+
+class C19
+{
+    public static C19 operator +(C19 x, C19 y) => throw null;
+    public static C19 operator checked +(C19 x, C19 y) => throw null;
+    public static explicit operator int(C19 x) => throw null;
+    public static explicit operator checked int(C19 x) => throw null;
+
+    void Run(C19 c)
+    {
+        // Viable callables: C19.op_Addition()
+        var c1 = c + c;
+
+        // Viable callables: C19.op_CheckedAddition()
+        var c2 = checked(c + c);
+
+        // Viable callables: C19.op_Explicit()
+        var n1 = (int)c;
+
+        // Viable callables: C19.op_CheckedExplicit()
+        var n2 = checked((int)c);
+    }
 }

csharp/ql/test/library-tests/dispatch/viableCallable.expected

@@ -268,3 +268,7 @@
 | ViableCallable.cs:423:9:423:21 | call to method M<String> | M<> | A5 |
 | ViableCallable.cs:478:9:478:14 | call to method M1 | M1 | C18 |
 | ViableCallable.cs:481:9:481:14 | call to method M2 | M2 | I2 |
+| ViableCallable.cs:495:18:495:22 | call to operator + | + | C19 |
+| ViableCallable.cs:498:26:498:30 | call to operator checked + | checked + | C19 |
+| ViableCallable.cs:501:18:501:23 | call to operator explicit conversion | explicit conversion | C19 |
+| ViableCallable.cs:504:26:504:31 | call to operator checked explicit conversion | checked explicit conversion | C19 |