Use 'ref locals' where necessary.

ICSharpCode.Decompiler/CSharp/Transforms/CustomPatterns.cs

@@ -40,7 +40,7 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 		{
 			ComposedType ct = other as ComposedType;
 			AstType o;
-			if (ct != null && !ct.HasNullableSpecifier && ct.PointerRank == 0 && !ct.ArraySpecifiers.Any()) {
+			if (ct != null && !ct.HasRefSpecifier && !ct.HasNullableSpecifier && ct.PointerRank == 0 && !ct.ArraySpecifiers.Any()) {
 				// Special case: ILSpy sometimes produces a ComposedType but then removed all array specifiers
 				// from it. In that case, we need to look at the base type for the annotations.
 				o = ct.BaseType;

ICSharpCode.Decompiler/CSharp/Transforms/DeclareVariables.cs

@@ -258,7 +258,11 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					continue;
 				
 				var boe = (v.InsertionPoint.nextNode as ExpressionStatement)?.Expression as AssignmentExpression;
-				if (boe != null && boe.Left.IsMatch(new IdentifierExpression(v.Name))) {
+				Expression expectedExpr = new IdentifierExpression(v.Name);
+				if (v.Type.Kind == TypeKind.ByReference) {
+					expectedExpr = new DirectionExpression(FieldDirection.Ref, expectedExpr);
+				}
+				if (boe != null && boe.Left.IsMatch(expectedExpr)) {
 					AstType type;
 					if (v.Type.ContainsAnonymousType()) {
 						type = new SimpleType("var");

ICSharpCode.Decompiler/Tests/RoundtripAssembly.cs

@@ -24,6 +24,7 @@ using System.Text.RegularExpressions;
 using ICSharpCode.Decompiler.CSharp;
 using ICSharpCode.Decompiler.Tests.Helpers;
 using ICSharpCode.NRefactory.Utils;
+using Microsoft.Win32;
 using Mono.Cecil;
 using NUnit.Framework;
 
@@ -32,7 +33,6 @@ namespace ICSharpCode.Decompiler.Tests
 	public class RoundtripAssembly
 	{
 		static readonly string testDir = Path.GetFullPath("../../../ILSpy-tests");
-		static readonly string msbuild = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), "msbuild", "14.0", "bin", "msbuild.exe");
 		static readonly string nunit = Path.Combine(testDir, "nunit", "nunit3-console.exe");
 		
 		[Test]
@@ -151,9 +151,26 @@ namespace ICSharpCode.Decompiler.Tests
 			}
 		}
 		
+		static string FindVS2017()
+		{
+			using (var key = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32)) {
+				using (var subkey = key.OpenSubKey(@"SOFTWARE\Microsoft\VisualStudio\SxS\VS7")) {
+					return subkey?.GetValue("15.0") as string;
+				}
+			}
+		}
+
+		static string FindMSBuild()
+		{
+			string vsPath = FindVS2017();
+			if (vsPath == null)
+				throw new InvalidOperationException("Could not find VS2017");
+			return Path.Combine(vsPath, @"MSBuild\15.0\bin\MSBuild.exe");
+		}
+
 		static void Compile(string projectFile, string outputDir)
 		{
-			var info = new ProcessStartInfo(msbuild);
+			var info = new ProcessStartInfo(FindMSBuild());
 			info.Arguments = $"/nologo /v:minimal /p:OutputPath=\"{outputDir}\" \"{projectFile}\"";
 			info.CreateNoWindow = true;
 			info.UseShellExecute = false;

NRefactory

@@ -1 +1 @@
-Subproject commit 2b10193ea20a26ae9c8db21a79c60f3be8d8cca8
+Subproject commit 3c638f6c43d77922e4a14c5af1b224e9563236f2