C#: Extract structs representing inline arrays as inline arrays.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/ElementAccess.cs

@@ -43,6 +43,9 @@ protected override void PopulateExpression(TextWriter trapFile)
 
         public sealed override Microsoft.CodeAnalysis.Location? ReportingLocation => base.ReportingLocation;
 
+        private static bool IsArray(ITypeSymbol symbol) =>
+            symbol.TypeKind == Microsoft.CodeAnalysis.TypeKind.Array || symbol.IsInlineArray();
+
         private static ExprKind GetKind(Context cx, ExpressionSyntax qualifier)
         {
             var qualifierType = cx.GetType(qualifier);
@@ -59,7 +62,7 @@ private static ExprKind GetKind(Context cx, ExpressionSyntax qualifier)
 
             return IsDynamic(cx, qualifier)
                 ? ExprKind.DYNAMIC_ELEMENT_ACCESS
-                : qualifierType.Symbol.TypeKind == Microsoft.CodeAnalysis.TypeKind.Array
+                : IsArray(qualifierType.Symbol)
                     ? ExprKind.ARRAY_ACCESS
                     : ExprKind.INDEXER_ACCESS;
         }

csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs

@@ -52,9 +52,15 @@ public Kinds.TypeKind GetTypeKind(Context cx, bool constructUnderlyingTupleType)
                     {
                         case TypeKind.Class: return Kinds.TypeKind.CLASS;
                         case TypeKind.Struct:
-                            return ((INamedTypeSymbol)Symbol).IsTupleType && !constructUnderlyingTupleType
-                                ? Kinds.TypeKind.TUPLE
-                                : Kinds.TypeKind.STRUCT;
+                            {
+                                if (((INamedTypeSymbol)Symbol).IsTupleType && !constructUnderlyingTupleType)
+                                {
+                                    return Kinds.TypeKind.TUPLE;
+                                }
+                                return Symbol.IsInlineArray() 
+                                    ? Kinds.TypeKind.INLINE_ARRAY
+                                    : Kinds.TypeKind.STRUCT;
+                            }
                         case TypeKind.Interface: return Kinds.TypeKind.INTERFACE;
                         case TypeKind.Array: return Kinds.TypeKind.ARRAY;
                         case TypeKind.Enum: return Kinds.TypeKind.ENUM;

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

@@ -524,6 +524,13 @@ public static bool IsBoundSpan(this ITypeSymbol type) =>
         public static bool IsUnboundReadOnlySpan(this ITypeSymbol type) =>
             type.ToString() == "System.ReadOnlySpan<T>";
 
+        public static bool IsInlineArray(this ITypeSymbol type)
+        {
+            var attributes = type.GetAttributes();
+            var isInline = attributes.Any(attribute => attribute.AttributeClass?.Name == "InlineArrayAttribute");
+            return isInline;
+        }
+
         /// <summary>
         /// Holds if this type is of the form <code>System.ReadOnlySpan<byte></code>.
         /// </summary>