C#: Fix named attribute argument extraction

Author: tamasvajk

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

@@ -69,11 +69,18 @@ private void ExtractArguments(TextWriter trapFile)
             var ctorArguments = attributeSyntax?.ArgumentList?.Arguments.Where(a => a.NameEquals == null).ToList();
 
             var childIndex = 0;
-            foreach (var constructorArgument in symbol.ConstructorArguments)
+            for (var i = 0; i < symbol.ConstructorArguments.Length; i++)
             {
-                var argSyntax = ctorArguments?.Count > childIndex
-                    ? ctorArguments[childIndex]
-                    : null;
+                var constructorArgument = symbol.ConstructorArguments[i];
+                var paramName = symbol.AttributeConstructor?.Parameters[i].Name;
+                var argSyntax = ctorArguments?.SingleOrDefault(a => a.NameColon != null && a.NameColon.Name.Identifier.Text == paramName);
+
+                if (argSyntax == null &&                            // couldn't find named argument
+                    ctorArguments?.Count > childIndex &&            // there're more arguments
+                    ctorArguments[childIndex].NameColon == null)    // the argument is positional
+                {
+                    argSyntax = ctorArguments[childIndex];
+                }
 
                 CreateExpressionFromArgument(
                     constructorArgument,

csharp/ql/test/library-tests/attributes/AttributeArguments.expected

@@ -47,10 +47,11 @@ arguments
 | attributes.cs:57:6:57:16 | [My(...)] | 0 | attributes.cs:57:18:57:21 | true |
 | attributes.cs:57:6:57:16 | [My(...)] | 1 | attributes.cs:57:28:57:29 | "" |
 | attributes.cs:57:6:57:16 | [My(...)] | 2 | attributes.cs:57:36:57:36 | 0 |
-| attributes.cs:58:6:58:8 | [My2(...)] | 0 | attributes.cs:58:10:58:13 | true |
-| attributes.cs:58:6:58:8 | [My2(...)] | 1 | attributes.cs:58:16:58:20 | false |
+| attributes.cs:58:6:58:8 | [My2(...)] | 0 | attributes.cs:58:28:58:32 | false |
+| attributes.cs:58:6:58:8 | [My2(...)] | 1 | attributes.cs:58:13:58:16 | true |
 | attributes.cs:58:6:58:8 | [My2(...)] | 2 | attributes.cs:58:6:58:8 | 12 |
-| attributes.cs:58:6:58:8 | [My2(...)] | 3 | attributes.cs:58:27:58:28 | 42 |
+| attributes.cs:58:6:58:8 | [My2(...)] | 3 | attributes.cs:58:22:58:22 | 1 |
+| attributes.cs:58:6:58:8 | [My2(...)] | 4 | attributes.cs:58:39:58:40 | 42 |
 | attributes.cs:77:2:77:5 | [Args(...)] | 0 | attributes.cs:77:7:77:8 | 42 |
 | attributes.cs:77:2:77:5 | [Args(...)] | 1 | attributes.cs:77:11:77:14 | null |
 | attributes.cs:77:2:77:5 | [Args(...)] | 2 | attributes.cs:77:17:77:25 | typeof(...) |
@@ -105,9 +106,10 @@ constructorArguments
 | attributes.cs:46:6:46:16 | [Conditional(...)] | 0 | attributes.cs:46:18:46:25 | "DEBUG2" |
 | attributes.cs:54:6:54:16 | [My(...)] | 0 | attributes.cs:54:18:54:22 | false |
 | attributes.cs:57:6:57:16 | [My(...)] | 0 | attributes.cs:57:18:57:21 | true |
-| attributes.cs:58:6:58:8 | [My2(...)] | 0 | attributes.cs:58:10:58:13 | true |
-| attributes.cs:58:6:58:8 | [My2(...)] | 1 | attributes.cs:58:16:58:20 | false |
+| attributes.cs:58:6:58:8 | [My2(...)] | 0 | attributes.cs:58:28:58:32 | false |
+| attributes.cs:58:6:58:8 | [My2(...)] | 1 | attributes.cs:58:13:58:16 | true |
 | attributes.cs:58:6:58:8 | [My2(...)] | 2 | attributes.cs:58:6:58:8 | 12 |
+| attributes.cs:58:6:58:8 | [My2(...)] | 3 | attributes.cs:58:22:58:22 | 1 |
 | attributes.cs:77:2:77:5 | [Args(...)] | 0 | attributes.cs:77:7:77:8 | 42 |
 | attributes.cs:77:2:77:5 | [Args(...)] | 1 | attributes.cs:77:11:77:14 | null |
 | attributes.cs:77:2:77:5 | [Args(...)] | 2 | attributes.cs:77:17:77:25 | typeof(...) |
@@ -126,6 +128,6 @@ namedArguments
 | attributes.cs:41:10:41:13 | [Args(...)] | Prop | attributes.cs:41:90:41:120 | array creation of type Object[] |
 | attributes.cs:57:6:57:16 | [My(...)] | x | attributes.cs:57:36:57:36 | 0 |
 | attributes.cs:57:6:57:16 | [My(...)] | y | attributes.cs:57:28:57:29 | "" |
-| attributes.cs:58:6:58:8 | [My2(...)] | X | attributes.cs:58:27:58:28 | 42 |
+| attributes.cs:58:6:58:8 | [My2(...)] | X | attributes.cs:58:39:58:40 | 42 |
 | attributes.cs:77:2:77:5 | [Args(...)] | Prop | attributes.cs:77:63:77:93 | array creation of type Object[] |
 | attributes.cs:80:6:80:9 | [Args(...)] | Prop | attributes.cs:80:68:80:98 | array creation of type Object[] |

csharp/ql/test/library-tests/attributes/PrintAst.expected

@@ -140,9 +140,10 @@ attributes.cs:
 #   57|         2: [IntLiteral] 0
 #   58|       2: [Attribute] [My2(...)]
 #   58|         -1: [TypeMention] My2Attribute
-#   58|         0: [BoolLiteral] true
-#   58|         1: [BoolLiteral] false
-#   58|         3: [IntLiteral] 42
+#   58|         0: [BoolLiteral] false
+#   58|         1: [BoolLiteral] true
+#   58|         3: [IntLiteral] 1
+#   58|         4: [IntLiteral] 42
 #   59|     4: [BlockStmt] {...}
 #   62| [Class] MyAttribute
 #-----|   3: (Base types)
@@ -268,4 +269,7 @@ attributes.cs:
 #   88|       2: [Parameter] i
 #   88|         -1: [TypeMention] int
 #   88|         1: [IntLiteral] 12
+#   88|       3: [Parameter] j
+#   88|         -1: [TypeMention] int
+#   88|         1: [IntLiteral] 13
 #   88|     4: [BlockStmt] {...}

csharp/ql/test/library-tests/attributes/attributes.cs

@@ -55,7 +55,7 @@ class Bar
     void M1() { }
 
     [MyAttribute(true, y = "", x = 0)]
-    [My2(true, false, X = 42)]
+    [My2(b: true, j: 1, a: false, X = 42)]
     void M2() { }
 }
 
@@ -85,5 +85,5 @@ public class X
 class My2Attribute : Attribute
 {
     public int X { get; set; }
-    public My2Attribute(bool a, bool b, int i = 12) { }
+    public My2Attribute(bool a, bool b, int i = 12, int j = 13) { }
 }