VB->C# convert region names in common cases - #15

Author: GrahamTheCoder

CodeConverter/Util/SyntaxNodeExtensions.cs

@@ -13,6 +13,7 @@
 using CompilationUnitSyntax = Microsoft.CodeAnalysis.CSharp.Syntax.CompilationUnitSyntax;
 using CSharpExtensions = Microsoft.CodeAnalysis.CSharp.CSharpExtensions;
 using VBSyntaxFactory = Microsoft.CodeAnalysis.VisualBasic.SyntaxFactory;
+using VBSyntax = Microsoft.CodeAnalysis.VisualBasic.Syntax;
 using VBSyntaxKind = Microsoft.CodeAnalysis.VisualBasic.SyntaxKind;
 using CSSyntaxKind = Microsoft.CodeAnalysis.CSharp.SyntaxKind;
 using FieldDeclarationSyntax = Microsoft.CodeAnalysis.CSharp.Syntax.FieldDeclarationSyntax;
@@ -369,6 +370,8 @@ public static IEnumerable<SyntaxTrivia> ConvertTrivia(this IReadOnlyCollection<S
 
         private static IEnumerable<SyntaxTrivia> ConvertVBTrivia(SyntaxTrivia t)
         {
+            var endOfLine = SyntaxFactory.EndOfLine(Environment.NewLine);
+
             if (t.IsKind(VBSyntaxKind.CommentTrivia)) {
                 yield return SyntaxFactory.SyntaxTrivia(CSSyntaxKind.SingleLineCommentTrivia, $"// {t.GetCommentText()}");
                 yield break;
@@ -394,6 +397,19 @@ private static IEnumerable<SyntaxTrivia> ConvertVBTrivia(SyntaxTrivia t)
                 yield break;
             }
 
+            if (t.HasStructure && t.GetStructure() is VBSyntax.RegionDirectiveTriviaSyntax rdts) {
+                var regionDirective = SyntaxFactory.RegionDirectiveTrivia(true);
+                var regionKeyword = regionDirective.RegionKeyword.WithTrailingTrivia(SyntaxFactory.Space);
+                var endOfDirectiveToken = regionDirective.EndOfDirectiveToken.WithLeadingTrivia(SyntaxFactory.PreprocessingMessage(rdts.Name.Text.Trim('"'))).WithTrailingTrivia(endOfLine);
+                yield return SyntaxFactory.Trivia(regionDirective.WithRegionKeyword(regionKeyword).WithEndOfDirectiveToken(endOfDirectiveToken));
+                yield break;
+            }
+
+            if (t.IsKind(VBSyntaxKind.EndRegionDirectiveTrivia)) {
+                yield return SyntaxFactory.Trivia(SyntaxFactory.EndRegionDirectiveTrivia(true).WithTrailingTrivia(endOfLine));
+                yield break;
+            }
+
             //Each of these would need its own method to recreate for C# with the right structure probably so let's just warn about them for now.
             var convertedKind = t.GetCSKind();
             yield return convertedKind.HasValue

Tests/CSharp/TriviaTests.cs

@@ -54,5 +54,48 @@ public void Deposit(int Item, bool ColaOnly, bool MonteCarloLogActive, Func<bool
     }
 }");
         }
+
+        [Fact]
+        public async Task Issue15_NestedRegionsAsync()
+        {
+            await TestConversionVisualBasicToCSharpAsync(
+@"#Region ""Whole File""
+#Region ""Nested""
+Imports System
+
+#Region ""Class""
+Module Program
+#Region ""Inside Class""
+    Sub Main(args As String())
+#Region ""Inside Method""
+        Console.WriteLine(""Hello World!"")
+#End Region
+    End Sub
+#End Region
+End Module
+#End Region
+#End Region
+#End Region
+",
+@"#region Whole File
+#region Nested
+using System;
+
+#region Class
+internal static partial class Program
+{
+    #region Inside Class
+    public static void Main(string[] args)
+    {
+        #region Inside Method
+        Console.WriteLine(""Hello World!"");
+        #endregion
+    }
+    #endregion
+}
+#endregion
+#endregion
+#endregion");
+        }
     }
 }