Merge pull request #18166 from tamasvajk/fix/db-quality-query-2

C#: Fix calls with no target in DB quality query

Author: tamasvajk

csharp/ql/src/Telemetry/DatabaseQuality.qll

@@ -68,24 +68,36 @@ module CallTargetStats implements StatsSig {
     )
   }
 
-  private predicate isInitializedWithCollectionInitializer(PropertyCall c) {
+  private predicate isInitializedWithObjectOrCollectionInitializer(PropertyCall c) {
     exists(Property p, AssignExpr assign |
       p = c.getProperty() and
       assign = c.getParent() and
       assign.getLValue() = c and
-      assign.getRValue() instanceof CollectionInitializer
+      assign.getRValue() instanceof ObjectOrCollectionInitializer
     )
   }
 
+  private predicate isEventFieldAccess(EventCall c) {
+    exists(Event e | c.getEvent() = e |
+      forall(Accessor a | e.getAnAccessor() = a | a.isCompilerGenerated())
+    )
+  }
+
+  private predicate isTypeParameterInstantiation(ObjectCreation e) {
+    e.getType() instanceof TypeParameter
+  }
+
   additional predicate isNotOkCall(Call c) {
     not exists(c.getTarget()) and
     not c instanceof DelegateCall and
     not c instanceof DynamicExpr and
     not isNoSetterPropertyCallInConstructor(c) and
     not isNoSetterPropertyInitialization(c) and
     not isAnonymousObjectMemberDeclaration(c) and
-    not isInitializedWithCollectionInitializer(c) and
-    not c.getParent+() instanceof NameOfExpr
+    not isInitializedWithObjectOrCollectionInitializer(c) and
+    not c.getParent+() instanceof NameOfExpr and
+    not isEventFieldAccess(c) and
+    not isTypeParameterInstantiation(c)
   }
 
   int getNumberOfNotOk() { result = count(Call c | isNotOkCall(c)) }

csharp/ql/test/query-tests/Telemetry/DatabaseQuality/IsNotOkayCall.expected

@@ -0,0 +1,4 @@
+| Quality.cs:26:19:26:26 | access to indexer | Call without target $@. | Quality.cs:26:19:26:26 | access to indexer | access to indexer |
+| Quality.cs:29:21:29:27 | access to indexer | Call without target $@. | Quality.cs:29:21:29:27 | access to indexer | access to indexer |
+| Quality.cs:32:9:32:21 | access to indexer | Call without target $@. | Quality.cs:32:9:32:21 | access to indexer | access to indexer |
+| Quality.cs:34:21:34:25 | object creation of type null | Call without target $@. | Quality.cs:34:21:34:25 | object creation of type null | object creation of type null |

csharp/ql/test/query-tests/Telemetry/DatabaseQuality/NoTarget.expected

@@ -4,4 +4,12 @@
 | Quality.cs:15:24:15:34 | access to property MyProperty3 | Call without target $@. | Quality.cs:15:24:15:34 | access to property MyProperty3 | access to property MyProperty3 |
 | Quality.cs:15:24:15:46 | access to property MyProperty2 | Call without target $@. | Quality.cs:15:24:15:46 | access to property MyProperty2 | access to property MyProperty2 |
 | Quality.cs:19:13:19:23 | access to property MyProperty4 | Call without target $@. | Quality.cs:19:13:19:23 | access to property MyProperty4 | access to property MyProperty4 |
-| Quality.cs:24:16:24:26 | access to property MyProperty2 | Call without target $@. | Quality.cs:24:16:24:26 | access to property MyProperty2 | access to property MyProperty2 |
+| Quality.cs:20:13:20:23 | access to property MyProperty6 | Call without target $@. | Quality.cs:20:13:20:23 | access to property MyProperty6 | access to property MyProperty6 |
+| Quality.cs:23:9:23:14 | access to event Event1 | Call without target $@. | Quality.cs:23:9:23:14 | access to event Event1 | access to event Event1 |
+| Quality.cs:23:9:23:30 | delegate call | Call without target $@. | Quality.cs:23:9:23:30 | delegate call | delegate call |
+| Quality.cs:26:19:26:26 | access to indexer | Call without target $@. | Quality.cs:26:19:26:26 | access to indexer | access to indexer |
+| Quality.cs:29:21:29:27 | access to indexer | Call without target $@. | Quality.cs:29:21:29:27 | access to indexer | access to indexer |
+| Quality.cs:32:9:32:21 | access to indexer | Call without target $@. | Quality.cs:32:9:32:21 | access to indexer | access to indexer |
+| Quality.cs:34:21:34:25 | object creation of type null | Call without target $@. | Quality.cs:34:21:34:25 | object creation of type null | object creation of type null |
+| Quality.cs:38:16:38:26 | access to property MyProperty2 | Call without target $@. | Quality.cs:38:16:38:26 | access to property MyProperty2 | access to property MyProperty2 |
+| Quality.cs:50:20:50:26 | object creation of type T | Call without target $@. | Quality.cs:50:20:50:26 | object creation of type T | object creation of type T |

csharp/ql/test/query-tests/Telemetry/DatabaseQuality/Quality.cs

@@ -16,13 +16,43 @@ public Test()
 
         new Test()
         {
-            MyProperty4 = { 1, 2, 3 }
+            MyProperty4 = { 1, 2, 3 },
+            MyProperty6 = { [1] = "" }
         };
+
+        Event1.Invoke(this, 5);
+
+        var str = "abcd";
+        var sub = str[..3];         // TODO: this is not an indexer call, but rather a `str.Substring(0, 3)` call.
+
+        Span<int> sp = null;
+        var slice = sp[..3];        // TODO: this is not an indexer call, but rather a `sp.Slice(0, 3)` call.
+
+        Span<byte> guidBytes = stackalloc byte[16];
+        guidBytes[08] = 1;          // TODO: this indexer call has no target, because the target is a `ref` returning getter.
+
+        new MyList([new(), new Test()]);        // TODO: the `new()` call has no target, which is unexpected, as we know at compile time, that this is a `new Test()` call.
     }
 
     public int MyProperty1 { get; }
     public int MyProperty2 { get; } = 42;
     public Test MyProperty3 { get; set; }
     public List<int> MyProperty4 { get; }
     static int MyProperty5 { get; }
+    public Dictionary<int, string> MyProperty6 { get; }
+
+    public event EventHandler<int> Event1;
+
+    class Gen<T> where T : new()
+    {
+        public static T Factory()
+        {
+            return new T();
+        }
+    }
+
+    class MyList
+    {
+        public MyList(IEnumerable<Test> init) { }
+    }
 }