Improve generated code recognition (#911)

its/projects/AutoGeneratedFiles/autogenerated_comment.cs

@@ -3,7 +3,7 @@
 using System;
 namespace SomeNamespace
 {
-    class Class_01
+    class Class_01_1
     {
         static void Method(string[] args)
         {

its/projects/AutoGeneratedFiles/autogenerated_comment2.cs

@@ -4,7 +4,7 @@
 
 namespace SomeNamespace
 {
-    class Class_02
+    class Class_01_2
     {
         static void Method(string[] args)
         {

its/projects/AutoGeneratedFiles/autogenerated_comment3.cs

@@ -0,0 +1,15 @@
+// Generated by the protocol buffer compiler. DO NOT EDIT!
+
+using System;
+
+namespace SomeNamespace
+{
+    class Class_01_3
+    {
+        static void Method(string[] args)
+        {
+            object obj = null;
+            Console.WriteLine(obj.ToString());
+        }
+    }
+}

its/projects/AutoGeneratedFiles/autogenerated_comment4.cs

@@ -0,0 +1,21 @@
+/*
+ * No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)
+ *
+ * OpenAPI spec version: 1.0.0
+ *
+ * Generated by: https://github.com/swagger-api/swagger-codegen.git
+ */
+
+using System;
+
+namespace SomeNamespace
+{
+    class Class_01_4
+    {
+        static void Method(string[] args)
+        {
+            object obj = null;
+            Console.WriteLine(obj.ToString());
+        }
+    }
+}

sonaranalyzer-dotnet/src/SonarAnalyzer.Common/Helpers/GeneratedCodeRecognizer.cs

@@ -45,7 +45,8 @@ public virtual bool IsGenerated(SyntaxTree tree)
         private static readonly string[] AutoGeneratedCommentParts =
             {
                 "<AUTO-GENERATED",
-                "<AUTOGENERATED"
+                "<AUTOGENERATED",
+                "GENERATED BY"
             };
         private static readonly string[] GeneratedCodeAttributes =
             {
@@ -83,14 +84,13 @@ private bool HasAutoGeneratedComment(SyntaxTree tree)
                 return false;
             }
 
-            var trivia = firstToken.LeadingTrivia;
-
-            var comments = trivia.Where(IsTriviaComment);
-            return comments.Any(t =>
-            {
-                var commentText = t.ToString().ToUpperInvariant();
-                return AutoGeneratedCommentParts.Any(part => commentText.Contains(part));
-            });
+            return firstToken.LeadingTrivia
+                .Where(IsTriviaComment)
+                .Any(trivia =>
+                {
+                    var commentText = trivia.ToString().ToUpperInvariant();
+                    return AutoGeneratedCommentParts.Any(part => commentText.Contains(part));
+                });
         }
 
         private bool HasGeneratedCodeAttribute(SyntaxTree tree)

sonaranalyzer-dotnet/src/Tests/SonarAnalyzer.UnitTest/Helpers/DiagnosticAnalyzerContextHelperTest.cs

@@ -18,13 +18,13 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
+using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using SonarAnalyzer.Helpers;
-using System.Linq;
-using System.Threading.Tasks;
 using CS = SonarAnalyzer.Rules.CSharp;
 using VB = SonarAnalyzer.Rules.VisualBasic;
 
@@ -130,6 +130,19 @@ void M()
 }";
             VerifyEmpty("test.cs", sourceCs, new CS.EmptyStatement());
 
+            sourceCs =
+@"/*
+ * No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)
+ *
+ * OpenAPI spec version: 1.0.0
+ *
+ * Generated by: https://github.com/swagger-api/swagger-codegen.git
+ */";
+            VerifyEmpty("test.cs", sourceCs, new CS.EmptyStatement());
+
+            sourceCs = "// Generated by the protocol buffer compiler.  DO NOT EDIT!";
+            VerifyEmpty("test.cs", sourceCs, new CS.EmptyStatement());
+
 
             const string sourceVb =
 @"'------------------------------------------------------------------------------