C#: Introduce extractor support for scoped variables and parameters.

Author: michaelnebel

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

@@ -59,6 +59,19 @@ protected void PopulateRefKind(TextWriter trapFile, RefKind kind)
             }
         }
 
+        protected void PopulateScopedKind(TextWriter trapFile, ScopedKind kind)
+        {
+            switch (kind)
+            {
+                case ScopedKind.ScopedRef:
+                    trapFile.scoped_annotation(this, Kinds.ScopedAnnotation.ScopedRef);
+                    break;
+                case ScopedKind.ScopedValue:
+                    trapFile.scoped_annotation(this, Kinds.ScopedAnnotation.ScopedValue);
+                    break;
+            }
+        }
+
         protected void ExtractCompilerGenerated(TextWriter trapFile)
         {
             if (Symbol.IsImplicitlyDeclared)

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

@@ -32,6 +32,7 @@ public void PopulateManual(Expression parent, bool isVar)
                 trapFile.localvars(this, kind, Symbol.Name, @var, Type.Create(Context, type).TypeRef, parent);
 
                 PopulateNullability(trapFile, local.GetAnnotatedType());
+                PopulateScopedKind(trapFile, local.ScopedKind);
                 if (local.IsRef)
                     trapFile.type_annotation(this, Kinds.TypeAnnotation.Ref);
             }

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

@@ -100,6 +100,7 @@ public override void Populate(TextWriter trapFile)
             PopulateAttributes();
             PopulateNullability(trapFile, Symbol.GetAnnotatedType());
             PopulateRefKind(trapFile, Symbol.RefKind);
+            PopulateScopedKind(trapFile, Symbol.ScopedKind);
 
             if (Symbol.Name != Original.Symbol.Name)
                 Context.ModelError(Symbol, "Inconsistent parameter declaration");

csharp/extractor/Semmle.Extraction.CSharp/Kinds/ScopedAnnotation.cs

@@ -0,0 +1,8 @@
+namespace Semmle.Extraction.Kinds;
+
+public enum ScopedAnnotation
+{
+    None = 0,
+    ScopedRef = 1,
+    ScopedValue = 2
+}

csharp/extractor/Semmle.Extraction.CSharp/Tuples.cs

@@ -462,5 +462,8 @@ internal static void locations_mapped(this System.IO.TextWriter trapFile, NonGen
 
         internal static void file_extraction_mode(this System.IO.TextWriter trapFile, Entities.File file, ExtractorMode mode) =>
             trapFile.WriteTuple("file_extraction_mode", file, mode);
+
+        internal static void scoped_annotation(this TextWriter trapFile, IEntity element, ScopedAnnotation @scoped) =>
+            trapFile.WriteTuple("scoped_annotation", element, (int)@scoped);
     }
 }