Investigate RegexNeedsTimeoutAnalyzer: Identify Roslyn 3.6.0 compatibility limitation with C# 9 target-typed new expressions

Philips.CodeAnalysis.MaintainabilityAnalyzers/Maintainability/AvoidStringFormatInInterpolatedStringAnalyzer.cs

@@ -58,4 +58,4 @@ private bool ContainsStringFormatCall(ExpressionSyntax expression)
 			return false;
 		}
 	}
-}
+}

Philips.CodeAnalysis.MaintainabilityAnalyzers/Maintainability/AvoidToStringOnStringAnalyzer.cs

@@ -56,4 +56,4 @@ public override void Analyze()
 			}
 		}
 	}
-}
+}

Philips.CodeAnalysis.MaintainabilityAnalyzers/Maintainability/AvoidToStringOnStringCodeFixProvider.cs

@@ -39,4 +39,4 @@ protected override async Task<Document> ApplyFix(Document document, InvocationEx
 			return document.WithSyntaxRoot(rootNode);
 		}
 	}
-}
+}

Philips.CodeAnalysis.SecurityAnalyzers/RegexNeedsTimeoutAnalyzer.cs

@@ -39,14 +39,18 @@ private void Analyze(SyntaxNodeAnalysisContext context)
 				return;
 			}
 
-			// Bail out early.
-			TypeSyntax typeSyntax = creation.Type;
-			if (!typeSyntax.ToString().Contains("Regex"))
+			TypeInfo typeInfo = context.SemanticModel.GetTypeInfo(creation);
+			ITypeSymbol typeSymbol = typeInfo.Type;
+			var usedConvertedType = false;
+
+			// For implicit constructors like new (".*"), Type might be a tuple (?, ?) but ConvertedType has the actual type
+			// Only use ConvertedType if Type is null or appears to be an incomplete/invalid type
+			if (typeSymbol == null || typeSymbol.ToString().Contains("?"))
 			{
-				return;
+				typeSymbol = typeInfo.ConvertedType;
+				usedConvertedType = true;
 			}
 
-			ITypeSymbol typeSymbol = context.SemanticModel.GetTypeInfo(creation).Type;
 			if (typeSymbol == null)
 			{
 				return;
@@ -58,21 +62,33 @@ private void Analyze(SyntaxNodeAnalysisContext context)
 				return;
 			}
 
+			// Skip incomplete implicit constructor nodes that have no arguments but are resolved via ConvertedType
+			// These appear to be parser artifacts and the real analysis happens on the complete nodes
+			if (usedConvertedType && creation.ArgumentList?.Arguments.Count == 0)
+			{
+				return;
+			}
+
+			AnalyzeCreation(context, creation.ArgumentList);
+		}
+
+		private void AnalyzeCreation(SyntaxNodeAnalysisContext context, ArgumentListSyntax argumentList)
+		{
 			// We require to use the constructor with the Timeout argument.
-			if (creation.ArgumentList is not { Arguments.Count: not CorrectConstructorArgumentCount })
+			if (argumentList is not { Arguments.Count: not CorrectConstructorArgumentCount })
 			{
 				return;
 			}
 
 			// NET7 has RegexOptions.NonBacktracking, which we also accept.
-			if (creation.ArgumentList.ToString().Contains("NonBacktracking"))
+			if (argumentList.ToString().Contains("NonBacktracking"))
 			{
 				return;
 			}
 
-			Location location = creation.ArgumentList.GetLocation();
+			Location location = argumentList.GetLocation();
 			var diagnostic = Diagnostic.Create(Rule, location);
 			context.ReportDiagnostic(diagnostic);
 		}
 	}
-}
+}

Philips.CodeAnalysis.Test/Security/RegexNeedsTimeoutAnalyzerTest.cs

@@ -48,9 +48,8 @@ public Regex MethodA()
 		}
 
 		[DataTestMethod]
-		// NOTE: Implicit names are not currently detected by this analyzer.
-		//[DataRow(@"("".*"", RegexOptions.Compiled)")]
-		//[DataRow(@"("".*"")")]
+		[DataRow(@"("".*"", RegexOptions.Compiled)")]
+		[DataRow(@"("".*"")")]
 		[DataRow(@"Regex("".*"", RegexOptions.Compiled)")]
 		[DataRow(@"Regex("".*"")")]
 		[DataRow(@"System.Text.RegularExpressions.Regex("".*"", RegexOptions.Compiled)")]