ILSpy/ICSharpCode.Decompiler/CSharp/Transforms/FlattenSwitchBlocks.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ICSharpCode.Decompiler.CSharp.Syntax;

namespace ICSharpCode.Decompiler.CSharp.Transforms
{
	class FlattenSwitchBlocks : IAstTransform
	{
		public void Run(AstNode rootNode, TransformContext context)
		{
			foreach (var switchSection in rootNode.Descendants.OfType<SwitchSection>())
			{
				if (switchSection.Statements.Count != 1)
					continue;

				var blockStatement = switchSection.Statements.First() as BlockStatement;
				if (blockStatement == null || blockStatement.Statements.Any(st => st is VariableDeclarationStatement))
					continue;

				blockStatement.Remove();
				blockStatement.Statements.MoveTo(switchSection.Statements);
			}
		}
	}
}