Added a rule to remove #region/#endregion directives.

src/Microsoft.DotNet.CodeFormatting.Tests/Microsoft.DotNet.CodeFormatting.Tests.csproj

@@ -96,6 +96,7 @@
     <Compile Include="Rules\PrivateFieldNamingRuleTests.cs" />
     <Compile Include="Rules\NonAsciiCharactersAreEscapedInLiteralsRuleTests.cs" />
     <Compile Include="Rules\MarkReadonlyFieldTests.cs" />
+    <Compile Include="Rules\RemoveRegionsTests.cs" />
     <Compile Include="Rules\UsingLocationRuleTests.cs" />
   </ItemGroup>
   <ItemGroup>

src/Microsoft.DotNet.CodeFormatting.Tests/Rules/RemoveRegionsTests.cs

@@ -0,0 +1,54 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Xunit;
+
+namespace Microsoft.DotNet.CodeFormatting.Tests
+{
+	public class RemoveRegionsTests : SyntaxRuleTestBase
+	{
+		internal override ISyntaxFormattingRule Rule
+		{
+			get
+			{
+				return new Rules.RemoveRegionsRule();
+			}
+		}
+
+		[Fact]
+		public void TestRemoveRegions()
+		{
+			var text = @"
+#region Region 1
+
+//comment
+#endregion Region 1
+
+class WithRegions
+{
+	#region have region here
+	public static void DoNothing()
+	{
+		#region inside method
+
+		#endregion inside method
+	}
+#endregion   
+}
+";
+			var expected = @"
+
+//comment
+
+class WithRegions
+{
+    public static void DoNothing()
+    {
+
+    }
+}
+";
+			Verify(text, expected);
+		}
+	}
+}

src/Microsoft.DotNet.CodeFormatting/Microsoft.DotNet.CodeFormatting.csproj

@@ -72,6 +72,7 @@
     <Compile Include="NameHelper.cs" />
     <Compile Include="ResponseFileWorkspace.cs" />
     <Compile Include="Rules\MarkReadonlyFieldsRule.cs" />
+    <Compile Include="Rules\RemoveRegionsRule.cs" />
     <Compile Include="SemaphoreLock.cs" />
     <Compile Include="SyntaxUtil.cs" />
     <Compile Include="Filters\FilenameFilter.cs" />

src/Microsoft.DotNet.CodeFormatting/Rules/RemoveRegionsRule.cs

@@ -0,0 +1,52 @@
+// Copyright(c) Microsoft.All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace Microsoft.DotNet.CodeFormatting.Rules
+{
+    [SyntaxRule(RemoveRegionsRule.Name, RemoveRegionsRule.Description, SyntaxRuleOrder.RemoveRegionsRule, DefaultRule = false)]
+    internal sealed class RemoveRegionsRule : CSharpOnlyFormattingRule, ISyntaxFormattingRule
+    {
+        internal const string Name = "RemoveRegions";
+        internal const string Description = "Removes all regions";
+
+        public SyntaxNode Process(SyntaxNode targetNode, string languageName)
+        {
+            var finder = new RegionFinder();
+            finder.Visit(targetNode);
+            var results = finder.Results;
+
+            if (results.Count > 0)
+            {
+                return targetNode.ReplaceTrivia(results,
+                    (arg1, arg2) => new SyntaxTrivia());
+            }
+            return targetNode;
+        }
+
+        private class RegionFinder : CSharpSyntaxWalker
+        {
+            public List<SyntaxTrivia> Results { get; } = new List<SyntaxTrivia>();
+
+            public RegionFinder()
+                : base(SyntaxWalkerDepth.StructuredTrivia)
+            {
+            }
+
+            public override void VisitRegionDirectiveTrivia(RegionDirectiveTriviaSyntax node)
+            {
+                Results.Add(node.ParentTrivia);
+            }
+
+            public override void VisitEndRegionDirectiveTrivia(EndRegionDirectiveTriviaSyntax node)
+            {
+                Results.Add(node.ParentTrivia);
+            }
+        }
+    }
+}

src/Microsoft.DotNet.CodeFormatting/Rules/RuleOrder.cs

@@ -18,6 +18,7 @@ internal static class SyntaxRuleOrder
         public const int BraceNewLineRule = 4;
         public const int NonAsciiChractersAreEscapedInLiterals = 5;
         public const int CopyrightHeaderRule = 6;
+        public const int RemoveRegionsRule = 7;
     }
 
     // Please keep these values sorted by number, not rule name.