C#: Extractor- and library support for explicit interface implementations for operators.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/Conversion.cs

@@ -10,6 +10,8 @@ internal class Conversion : UserOperator
         private Conversion(Context cx, IMethodSymbol init)
             : base(cx, init) { }
 
+        protected override MethodKind ExplicitlyImplementsKind => MethodKind.Conversion;
+
         public static new Conversion Create(Context cx, IMethodSymbol symbol) =>
             ConversionFactory.Instance.CreateEntityFromSymbol(cx, symbol);
 

csharp/extractor/Semmle.Extraction.CSharp/Entities/Method.cs

@@ -83,10 +83,12 @@ public static void NumberOfLines(TextWriter trapFile, ISymbol symbol, IEntity ca
             }
         }
 
+        protected virtual MethodKind ExplicitlyImplementsKind => MethodKind.Ordinary;
+
         public void Overrides(TextWriter trapFile)
         {
             foreach (var explicitInterface in Symbol.ExplicitInterfaceImplementations
-                .Where(sym => sym.MethodKind == MethodKind.Ordinary)
+                .Where(sym => sym.MethodKind == ExplicitlyImplementsKind)
                 .Select(impl => Type.Create(Context, impl.ContainingType)))
             {
                 trapFile.explicitly_implements(this, explicitInterface.TypeRef);

csharp/extractor/Semmle.Extraction.CSharp/Entities/UserOperator.cs

@@ -11,6 +11,8 @@ internal class UserOperator : Method
         protected UserOperator(Context cx, IMethodSymbol init)
             : base(cx, init) { }
 
+        protected override MethodKind ExplicitlyImplementsKind => MethodKind.UserDefinedOperator;
+
         public override void Populate(TextWriter trapFile)
         {
             PopulateMethod(trapFile);
@@ -37,6 +39,7 @@ public override void Populate(TextWriter trapFile)
             }
 
             ContainingType.PopulateGenerics();
+            Overrides(trapFile);
         }
 
         public override bool NeedsPopulation => Context.Defines(Symbol) || IsImplicitOperator(out _);

csharp/ql/lib/semmle/code/csharp/Callable.qll

@@ -434,7 +434,7 @@ class Destructor extends DotNet::Destructor, Callable, Member, Attributable, @de
  * Either a unary operator (`UnaryOperator`), a binary operator
  * (`BinaryOperator`), or a conversion operator (`ConversionOperator`).
  */
-class Operator extends Callable, Member, Attributable, @operator {
+class Operator extends Callable, Member, Attributable, Overridable, @operator {
   /**
    * DEPRECATED: use `getFunctionName()` instead.
    *