Merge pull request #4656 from tamasvajk/feature/csharp9-not-pattern

C#: Extract unary patterns

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Patterns/Pattern.cs

@@ -20,6 +20,9 @@ namespace Semmle.Extraction.CSharp.Entities.Expressions
                 case TypePatternSyntax typePattern:
                     return Expressions.TypeAccess.Create(cx, typePattern.Type, parent, child);
 
+                case UnaryPatternSyntax unaryPattern:
+                    return new UnaryPattern(cx, unaryPattern, parent, child);
+
                 case DeclarationPatternSyntax declPattern:
                     // Creates a single local variable declaration.
                     {

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Patterns/UnaryPattern.cs

@@ -0,0 +1,15 @@
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Semmle.Extraction.Entities;
+using Semmle.Extraction.Kinds;
+
+namespace Semmle.Extraction.CSharp.Entities.Expressions
+{
+    internal class UnaryPattern : Expression
+    {
+        public UnaryPattern(Context cx, UnaryPatternSyntax syntax, IExpressionParentEntity parent, int child) :
+            base(new ExpressionInfo(cx, NullType.Create(cx), cx.Create(syntax.GetLocation()), ExprKind.NOT_PATTERN, parent, child, false, null))
+        {
+            Pattern.Create(cx, syntax.Pattern, this, 0);
+        }
+    }
+}

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

@@ -115,6 +115,7 @@ namespace Semmle.Extraction.Kinds
         SWITCH_CASE = 118,
         ASSIGN_COALESCE = 119,
         SUPPRESS_NULLABLE_WARNING = 120,
-        NAMESPACE_ACCESS = 121
+        NAMESPACE_ACCESS = 121,
+        NOT_PATTERN = 126
     }
 }