Merge branch 'master' of https://github.com/icsharpcode/ILSpy into fancy-tooltips

BuildTools/appveyor-install.ps1

@@ -4,7 +4,7 @@ $baseCommit = "d779383cb85003d6dabeb976f0845631e07bf463";
 $baseCommitRev = 1;
 
 # make sure this list matches artifacts-only branches list in appveyor.yml!
-$masterBranches = @("master", "3.2.x");
+$masterBranches = @("master", "5.0.x");
 
 $globalAssemblyInfoTemplateFile = "ILSpy/Properties/AssemblyInfo.template.cs";
 

BuildTools/pipelines-install.ps1

@@ -4,7 +4,7 @@ $baseCommit = "d779383cb85003d6dabeb976f0845631e07bf463";
 $baseCommitRev = 1;
 
 # make sure this list matches artifacts-only branches list in azure-pipelines.yml!
-$masterBranches = @("master", "3.2.x");
+$masterBranches = @("master", "5.0.x");
 
 $globalAssemblyInfoTemplateFile = "ILSpy/Properties/AssemblyInfo.template.cs";
 

BuildTools/update-assemblyinfo.ps1

@@ -4,7 +4,7 @@ $baseCommit = "d779383cb85003d6dabeb976f0845631e07bf463";
 $baseCommitRev = 1;
 
 # make sure this list matches artifacts-only branches list in appveyor.yml!
-$masterBranches = @("master", "3.2.x");
+$masterBranches = @("master", "5.0.x");
 
 $globalAssemblyInfoTemplateFile = "ILSpy/Properties/AssemblyInfo.template.cs";
 

ICSharpCode.Decompiler.Tests/CorrectnessTestRunner.cs

@@ -280,6 +280,12 @@ namespace ICSharpCode.Decompiler.Tests
 			RunCS(options: options);
 		}
 
+		[Test]
+		public void StringConcat([ValueSource("defaultOptions")] CompilerOptions options)
+		{
+			RunCS(options: options);
+		}
+
 		[Test]
 		public void MiniJSON([ValueSource("defaultOptions")] CompilerOptions options)
 		{

ICSharpCode.Decompiler.Tests/Helpers/Tester.cs

@@ -224,6 +224,7 @@ namespace ICSharpCode.Decompiler.Tests.Helpers
 				preprocessorSymbols.Add("CS71");
 				preprocessorSymbols.Add("CS72");
 				preprocessorSymbols.Add("CS73");
+				preprocessorSymbols.Add("CS80");
 				preprocessorSymbols.Add("VB11");
 				preprocessorSymbols.Add("VB14");
 				preprocessorSymbols.Add("VB15");

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -42,8 +42,8 @@
   <ItemGroup>
     <PackageReference Include="DiffLib" Version="2017.7.26.1241" />
     <PackageReference Include="Microsoft.Build.Locator" Version="1.2.2" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.3.0-beta1-final" />
-    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.3.0-beta1-final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.3.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.3.1" />
     <PackageReference Include="Microsoft.DiaSymReader.Converter.Xml" Version="1.1.0-beta1-63314-01" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.13.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
@@ -79,9 +79,12 @@
 
   <ItemGroup>
     <Compile Include="DisassemblerPrettyTestRunner.cs" />
+    <Compile Include="TestCases\Correctness\StringConcat.cs" />
     <Compile Include="TestCases\ILPretty\ConstantBlobs.cs" />
     <Compile Include="TestCases\Pretty\OutVariables.cs" />
     <Compile Include="TestCases\Pretty\CustomTaskType.cs" />
+    <None Include="TestCases\Ugly\NoExtensionMethods.Expected.cs" />
+    <Compile Include="TestCases\Ugly\NoExtensionMethods.cs" />
     <None Include="TestCases\VBPretty\VBCompoundAssign.cs" />
     <Compile Include="TestCases\Pretty\ThrowExpressions.cs" />
     <None Include="TestCases\ILPretty\Issue1145.cs" />

ICSharpCode.Decompiler.Tests/TestCases/Correctness/FloatingPointArithmetic.cs

@@ -7,6 +7,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 		public static int Main(string[] args)
 		{
 			Issue999();
+			Issue1656();
 			return 0;
 		}
 
@@ -20,5 +21,21 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 		{
 			return 0.99f * v + 0.01f;
 		}
+
+		static void Issue1656()
+		{
+			double primary = 'B';
+			CxAssert((++primary) == 'C');
+			CxAssert((--primary) == 'B');
+			CxAssert((primary++) == 'B');
+			CxAssert((primary--) == 'C');
+		}
+
+		static void CxAssert(bool v)
+		{
+			if (!v) {
+				throw new InvalidOperationException();
+			}
+		}
 	}
 }

ICSharpCode.Decompiler.Tests/TestCases/Correctness/NullableTests.cs

@@ -23,6 +23,12 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 	class NullableTests
 	{
 		static void Main()
+		{
+			AvoidLifting();
+			BitNot();
+		}
+
+		static void AvoidLifting()
 		{
 			Console.WriteLine("MayThrow:");
 			Console.WriteLine(MayThrow(10, 2, 3));
@@ -33,8 +39,8 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 			Console.WriteLine(NotUsingAllInputs(5, null));
 
 			Console.WriteLine("UsingUntestedValue:");
-			Console.WriteLine(NotUsingAllInputs(5, 3));
-			Console.WriteLine(NotUsingAllInputs(5, null));
+			Console.WriteLine(UsingUntestedValue(5, 3));
+			Console.WriteLine(UsingUntestedValue(5, null));
 		}
 
 		static int? MayThrow(int? a, int? b, int? c)
@@ -54,5 +60,27 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 			// cannot be lifted because the value differs if b == null
 			return a.HasValue ? a.GetValueOrDefault() + b.GetValueOrDefault() : default(int?);
 		}
+
+		static void BitNot()
+		{
+			UInt32? value = 0;
+			Assert(~value == UInt32.MaxValue);
+			UInt64? value2 = 0;
+			Assert(~value2 == UInt64.MaxValue);
+			UInt16? value3 = 0;
+			Assert((UInt16)~value3 == (UInt16)UInt16.MaxValue);
+			UInt32 value4 = 0;
+			Assert(~value4 == UInt32.MaxValue);
+			UInt64 value5 = 0;
+			Assert(~value5 == UInt64.MaxValue);
+			UInt16 value6 = 0;
+			Assert((UInt16)~value6 == UInt16.MaxValue);
+		}
+
+		static void Assert(bool b)
+		{
+			if (!b)
+				throw new InvalidOperationException();
+		}
 	}
 }

ICSharpCode.Decompiler.Tests/TestCases/Correctness/StringConcat.cs

@@ -0,0 +1,117 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
+{
+	class StringConcat
+	{
+		private class C
+		{
+			int i;
+
+			public C(int i)
+			{
+				Console.WriteLine("  new C(" + i + ")");
+				this.i = i;
+			}
+
+			public override string ToString()
+			{
+				Console.WriteLine("  C(" + i + ").ToString()");
+				return (i++).ToString();
+			}
+		}
+
+		private struct S
+		{
+			int i;
+
+			public S(int i)
+			{
+				Console.WriteLine("  new C(" + i + ")");
+				this.i = i;
+			}
+
+			public override string ToString()
+			{
+				Console.WriteLine("  S(" + i + ").ToString()");
+				return (i++).ToString();
+			}
+		}
+
+		static string Space()
+		{
+			Console.WriteLine("  Space()");
+			return " ";
+		}
+
+		static void TestClass()
+		{
+			Console.WriteLine("string + C:");
+			Console.WriteLine(Space() + new C(1));
+
+			Console.WriteLine("C + string:");
+			Console.WriteLine(new C(2) + Space());
+
+			Console.WriteLine("C + string + C:");
+			Console.WriteLine(new C(3) + Space() + new C(4));
+
+			Console.WriteLine("string + C + C:");
+			Console.WriteLine(Space() + new C(5) + new C(6));
+
+			Console.WriteLine("string.Concat(C, string, C):");
+			Console.WriteLine(string.Concat(new C(10), Space(), new C(11)));
+
+			Console.WriteLine("string.Concat(string.Concat(C, string), C):");
+			Console.WriteLine(string.Concat(string.Concat(new C(15), Space()), new C(16)));
+
+			Console.WriteLine("string.Concat(C, string.Concat(string, C)):");
+			Console.WriteLine(string.Concat(new C(20), string.Concat(Space(), new C(21))));
+
+			Console.WriteLine("string.Concat(C, string) + C:");
+			Console.WriteLine(string.Concat(new C(30), Space()) + new C(31));
+		}
+
+		static void TestStruct()
+		{
+			Console.WriteLine("string + S:");
+			Console.WriteLine(Space() + new S(1));
+
+			Console.WriteLine("S + string:");
+			Console.WriteLine(new S(2) + Space());
+
+			Console.WriteLine("S + string + S:");
+			Console.WriteLine(new S(3) + Space() + new S(4));
+
+			Console.WriteLine("string + S + S:");
+			Console.WriteLine(Space() + new S(5) + new S(6));
+
+			Console.WriteLine("string.Concat(S, string, S):");
+			Console.WriteLine(string.Concat(new S(10), Space(), new S(11)));
+
+			Console.WriteLine("string.Concat(string.Concat(S, string), S):");
+			Console.WriteLine(string.Concat(string.Concat(new S(15), Space()), new S(16)));
+
+			Console.WriteLine("string.Concat(S, string.Concat(string, S)):");
+			Console.WriteLine(string.Concat(new S(20), string.Concat(Space(), new S(21))));
+
+			Console.WriteLine("string.Concat(S, string) + S:");
+			Console.WriteLine(string.Concat(new S(30), Space()) + new S(31));
+		}
+
+		static void TestStructMutation()
+		{
+			Console.WriteLine("TestStructMutation:");
+			S s = new S(0);
+			Console.WriteLine(Space() + s);
+			Console.WriteLine(Space() + s.ToString());
+			Console.WriteLine(s);
+		}
+
+		static void Main()
+		{
+			TestClass();
+			TestStruct();
+			TestStructMutation();
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/CS1xSwitch_Debug.cs

@@ -270,7 +270,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 
 		public static string SwitchOverBool(bool b)
 		{
-			Console.WriteLine("SwitchOverBool: " + b.ToString());
+			Console.WriteLine("SwitchOverBool: " + b);
 			switch (b) {
 				case true:
 					return bool.TrueString;

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/CS1xSwitch_Release.cs

@@ -270,7 +270,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 
 		public static string SwitchOverBool(bool b)
 		{
-			Console.WriteLine("SwitchOverBool: " + b.ToString());
+			Console.WriteLine("SwitchOverBool: " + b);
 			switch (b) {
 				case true:
 					return bool.TrueString;

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/FSharpUsing_Debug.cs

@@ -36,7 +36,7 @@ public static class FSharpUsingPatterns
 			num = fileStream.ReadByte();
 		}
 		int num2 = num;
-		Console.WriteLine("read:" + num2.ToString());
+		Console.WriteLine("read:" + num2);
 	}
 
 	public static void sample5()

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/FSharpUsing_Release.cs

@@ -36,7 +36,7 @@ public static class FSharpUsingPatterns
 			num = fileStream.ReadByte();
 		}
 		int num2 = num;
-		Console.WriteLine("read:" + num2.ToString());
+		Console.WriteLine("read:" + num2);
 	}
 
 	public static void sample5()

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Async.cs

@@ -167,6 +167,24 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			};
 		}
 
+		public static async Task AlwaysThrow()
+		{
+			throw null;
+		}
+
+		public static async Task InfiniteLoop()
+		{
+			while (true) {
+			}
+		}
+
+		public static async Task InfiniteLoopWithAwait()
+		{
+			while (true) {
+				await Task.Delay(10);
+			}
+		}
+
 #if CS70
 		public static async Task<int> AsyncLocalFunctions()
 		{

ICSharpCode.Decompiler.Tests/TestCases/Pretty/CompoundAssignmentTest.cs

@@ -4562,9 +4562,9 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			// same temporary. In order to inline the generated value-type temporary, we
 			// need to split it, even though it has the address taken for the ToString() call.
 			if (flag) {
-				strings[1] += chars[i].ToString();
+				strings[1] += chars[i];
 			} else {
-				strings[0] += chars[i].ToString();
+				strings[0] += chars[i];
 			}
 		}
 #endif

ICSharpCode.Decompiler.Tests/TestCases/Pretty/CustomTaskType.cs

@@ -1,4 +1,6 @@
-using System;
+#pragma warning disable 1998
+
+using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 

ICSharpCode.Decompiler.Tests/TestCases/Pretty/ExpressionTrees.cs

@@ -1026,6 +1026,14 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			});
 		}
 
+		public static void StringConcat()
+		{
+			Test<Func<string, object, string>>(null, (string a, object b) => a + b);
+			Test<Func<string, object, string>>(null, (string a, object b) => a + b.ToString());
+			Test<Func<string, int, string>>(null, (string a, int b) => a + b);
+			Test<Func<string, int, string>>(null, (string a, int b) => a + b.ToString());
+		}
+
 		public async Task Issue1524(string str)
 		{
 			await Task.Delay(100);

ICSharpCode.Decompiler.Tests/TestCases/Pretty/InterfaceTests.cs

@@ -16,21 +16,101 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+// We can't test this because "error CS8701: Target runtime doesn't support default interface implementation."
+#undef CS80
+
+using System;
+
 namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 {
 	internal class InterfaceTests
 	{
 		public interface IA
 		{
+			int Property1 {
+				get;
+			}
+			int Property2 {
+				set;
+			}
+			int Property3 {
+				get;
+				set;
+			}
+
+			event EventHandler MyEvent;
+			void Method();
+
+#if CS80
+			void DefaultMethod()
+			{
+				Method();
+				PrivateMethod();
+			}
+
+			private void PrivateMethod()
+			{
+				Method();
+			}
+
+			internal void InternalMethod()
+			{
+				Method();
+			}
+
+			sealed void SealedMethod()
+			{
+				Method();
+			}
+
+			static void StaticMethod()
+			{
+
+			}
+#endif
 		}
 		public interface IA2 : IA
 		{
+#if CS80
+			void IA.InternalMethod()
+			{
+			}
+#endif
 		}
 		public interface IB
 		{
 		}
 		public class C : IA2, IA, IB
 		{
+			int IA.Property1 {
+				get {
+					throw new NotImplementedException();
+				}
+			}
+			int IA.Property2 {
+				set {
+					throw new NotImplementedException();
+				}
+			}
+			int IA.Property3 {
+				get {
+					throw new NotImplementedException();
+				}
+				set {
+					throw new NotImplementedException();
+				}
+			}
+
+			event EventHandler IA.MyEvent {
+				add {
+				}
+				remove {
+				}
+			}
+			void IA.Method()
+			{
+				throw new NotImplementedException();
+			}
 		}
 	}
 }

ICSharpCode.Decompiler.Tests/TestCases/Pretty/LocalFunctions.cs

@@ -310,6 +310,17 @@ namespace LocalFunctions
 			}
 		}
 
+		public void WriteCapturedParameter(int i)
+		{
+			ParamWrite();
+			Console.WriteLine(i);
+
+			void ParamWrite()
+			{
+				i++;
+			}
+		}
+
 		//public static void LocalFunctionInUsing()
 		//{
 		//	using (MemoryStream memoryStream = new MemoryStream()) {

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Loops.cs

@@ -401,7 +401,8 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 				Console.WriteLine("MoveNext");
 				if (enumerator.MoveNext()) {
 					object current = enumerator.Current;
-					Console.WriteLine("current: " + current);
+					Console.WriteLine("please don't inline 'current'");
+					Console.WriteLine(current);
 				}
 			} finally {
 				IDisposable disposable = enumerator as IDisposable;

ICSharpCode.Decompiler.Tests/TestCases/Pretty/RefLocalsAndReturns.cs

@@ -63,17 +63,68 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 		{
 			private readonly int dummy;
 
+			public int Property {
+				get {
+					return 1;
+				}
+				set {
+				}
+			}
+
+#if CS80
+			public readonly int ReadOnlyProperty {
+				get {
+					return 1;
+				}
+				set {
+				}
+			}
+
+			public int PropertyWithReadOnlyGetter {
+				readonly get {
+					return 1;
+				}
+				set {
+				}
+			}
+
+			public int PropertyWithReadOnlySetter {
+				get {
+					return 1;
+				}
+				readonly set {
+				}
+			}
+
+			public event EventHandler NormalEvent;
+
+			public readonly event EventHandler ReadOnlyEvent {
+				add {
+				}
+				remove {
+				}
+			}
+#endif
 			public void Method()
 			{
 			}
+
+#if CS80
+			public readonly void ReadOnlyMethod()
+			{
+			}
+#endif
 		}
 
 		public readonly struct ReadOnlyStruct
 		{
-			private readonly int dummy;
+			private readonly int Field;
 
 			public void Method()
 			{
+				ref readonly int field = ref Field;
+				Console.WriteLine("No inlining");
+				Console.WriteLine(field.GetHashCode());
 			}
 		}
 

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Switch.cs

@@ -366,7 +366,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 #if !ROSLYN
 		public static string SwitchOverBool(bool b)
 		{
-			Console.WriteLine("SwitchOverBool: " + b.ToString());
+			Console.WriteLine("SwitchOverBool: " + b);
 			switch (b) {
 				case true:
 					return bool.TrueString;

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Using.cs

@@ -90,7 +90,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 		private void UsingStatementOnNullableStruct(UsingStruct? us)
 		{
 			using (us) {
-				Console.WriteLine("using-body: " + us);
+				Console.WriteLine("using-body: " + us.ToString());
 			}
 		}
 

ICSharpCode.Decompiler.Tests/TestCases/Pretty/ValueTypes.cs

@@ -184,7 +184,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 		public static void Issue56(int i, out string str)
 		{
 			str = "qq";
-			str += i.ToString();
+			str += i;
 		}
 
 		public static void CopyAroundAndModifyField(S s)

ICSharpCode.Decompiler.Tests/TestCases/Ugly/NoExtensionMethods.Expected.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Runtime.CompilerServices;
+
+[assembly: Extension]
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Ugly
+{
+	[Extension]
+	internal static class NoExtensionMethods
+	{
+		[Extension]
+		internal static Func<T> AsFunc<T>(T value) where T : class
+		{
+			return new Func<T>(value, __ldftn(Return));
+		}
+
+		[Extension]
+		private static T Return<T>(T value)
+		{
+			return value;
+		}
+
+		internal static Func<int, int> ExtensionMethodAsStaticFunc()
+		{
+			return Return;
+		}
+
+		internal static Func<object> ExtensionMethodBoundToNull()
+		{
+			return new Func<object>(null, __ldftn(Return));
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/Ugly/NoExtensionMethods.cs

@@ -0,0 +1,27 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Ugly
+{
+	internal static class NoExtensionMethods
+	{
+		internal static Func<T> AsFunc<T>(this T value) where T : class
+		{
+			return new Func<T>(value.Return);
+		}
+
+		private static T Return<T>(this T value)
+		{
+			return value;
+		}
+
+		internal static Func<int, int> ExtensionMethodAsStaticFunc()
+		{
+			return Return;
+		}
+
+		internal static Func<object> ExtensionMethodBoundToNull()
+		{
+			return ((object)null).Return;
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/Ugly/NoExtensionMethods.opt.roslyn.il

@@ -0,0 +1,93 @@
+
+
+
+
+// Metadata version: v4.0.30319
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly NoExtensionMethods
+{
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilationRelaxationsAttribute::.ctor(int32) = ( 01 00 08 00 00 00 00 00 ) 
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.RuntimeCompatibilityAttribute::.ctor() = ( 01 00 01 00 54 02 16 57 72 61 70 4E 6F 6E 45 78   // ....T..WrapNonEx
+                                                                                                             63 65 70 74 69 6F 6E 54 68 72 6F 77 73 01 )       // ceptionThrows.
+
+  // --- The following custom attribute is added automatically, do not uncomment -------
+  //  .custom instance void [mscorlib]System.Diagnostics.DebuggableAttribute::.ctor(valuetype [mscorlib]System.Diagnostics.DebuggableAttribute/DebuggingModes) = ( 01 00 02 00 00 00 00 00 ) 
+
+  .permissionset reqmin
+             = {[mscorlib]System.Security.Permissions.SecurityPermissionAttribute = {property bool 'SkipVerification' = bool(true)}}
+  .hash algorithm 0x00008004
+  .ver 0:0:0:0
+}
+.module NoExtensionMethods.dll
+.custom instance void [mscorlib]System.Security.UnverifiableCodeAttribute::.ctor() = ( 01 00 00 00 ) 
+.imagebase 0x10000000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00000001    //  ILONLY
+
+
+// =============== CLASS MEMBERS DECLARATION ===================
+
+.class private abstract auto ansi sealed beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods
+       extends [mscorlib]System.Object
+{
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+  .method assembly hidebysig static class [mscorlib]System.Func`1<!!T> 
+          AsFunc<class T>(!!T 'value') cil managed
+  {
+    .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+    // Code size       18 (0x12)
+    .maxstack  8
+    IL_0000:  ldarg.0
+    IL_0001:  box        !!T
+    IL_0006:  ldftn      !!0 ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods::Return<!!0>(!!0)
+    IL_000c:  newobj     instance void class [mscorlib]System.Func`1<!!T>::.ctor(object,
+                                                                                 native int)
+    IL_0011:  ret
+  } // end of method NoExtensionMethods::AsFunc
+
+  .method private hidebysig static !!T  Return<T>(!!T 'value') cil managed
+  {
+    .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+    // Code size       2 (0x2)
+    .maxstack  8
+    IL_0000:  ldarg.0
+    IL_0001:  ret
+  } // end of method NoExtensionMethods::Return
+
+  .method assembly hidebysig static class [mscorlib]System.Func`2<int32,int32> 
+          ExtensionMethodAsStaticFunc() cil managed
+  {
+    // Code size       13 (0xd)
+    .maxstack  8
+    IL_0000:  ldnull
+    IL_0001:  ldftn      !!0 ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods::Return<int32>(!!0)
+    IL_0007:  newobj     instance void class [mscorlib]System.Func`2<int32,int32>::.ctor(object,
+                                                                                         native int)
+    IL_000c:  ret
+  } // end of method NoExtensionMethods::ExtensionMethodAsStaticFunc
+
+  .method assembly hidebysig static class [mscorlib]System.Func`1<object> 
+          ExtensionMethodBoundToNull() cil managed
+  {
+    // Code size       13 (0xd)
+    .maxstack  8
+    IL_0000:  ldnull
+    IL_0001:  ldftn      !!0 ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods::Return<object>(!!0)
+    IL_0007:  newobj     instance void class [mscorlib]System.Func`1<object>::.ctor(object,
+                                                                                    native int)
+    IL_000c:  ret
+  } // end of method NoExtensionMethods::ExtensionMethodBoundToNull
+
+} // end of class ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods
+
+
+// =============================================================
+
+// *********** DISASSEMBLY COMPLETE ***********************

ICSharpCode.Decompiler.Tests/TestCases/Ugly/NoExtensionMethods.roslyn.il

@@ -0,0 +1,117 @@
+
+
+
+
+// Metadata version: v4.0.30319
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly NoExtensionMethods
+{
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilationRelaxationsAttribute::.ctor(int32) = ( 01 00 08 00 00 00 00 00 ) 
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.RuntimeCompatibilityAttribute::.ctor() = ( 01 00 01 00 54 02 16 57 72 61 70 4E 6F 6E 45 78   // ....T..WrapNonEx
+                                                                                                             63 65 70 74 69 6F 6E 54 68 72 6F 77 73 01 )       // ceptionThrows.
+
+  // --- The following custom attribute is added automatically, do not uncomment -------
+  //  .custom instance void [mscorlib]System.Diagnostics.DebuggableAttribute::.ctor(valuetype [mscorlib]System.Diagnostics.DebuggableAttribute/DebuggingModes) = ( 01 00 07 01 00 00 00 00 ) 
+
+  .permissionset reqmin
+             = {[mscorlib]System.Security.Permissions.SecurityPermissionAttribute = {property bool 'SkipVerification' = bool(true)}}
+  .hash algorithm 0x00008004
+  .ver 0:0:0:0
+}
+.module NoExtensionMethods.dll
+.custom instance void [mscorlib]System.Security.UnverifiableCodeAttribute::.ctor() = ( 01 00 00 00 ) 
+.imagebase 0x10000000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00000001    //  ILONLY
+
+
+// =============== CLASS MEMBERS DECLARATION ===================
+
+.class private abstract auto ansi sealed beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods
+       extends [mscorlib]System.Object
+{
+  .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+  .method assembly hidebysig static class [mscorlib]System.Func`1<!!T> 
+          AsFunc<class T>(!!T 'value') cil managed
+  {
+    .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+    // Code size       23 (0x17)
+    .maxstack  2
+    .locals init (class [mscorlib]System.Func`1<!!T> V_0)
+    IL_0000:  nop
+    IL_0001:  ldarg.0
+    IL_0002:  box        !!T
+    IL_0007:  ldftn      !!0 ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods::Return<!!0>(!!0)
+    IL_000d:  newobj     instance void class [mscorlib]System.Func`1<!!T>::.ctor(object,
+                                                                                 native int)
+    IL_0012:  stloc.0
+    IL_0013:  br.s       IL_0015
+
+    IL_0015:  ldloc.0
+    IL_0016:  ret
+  } // end of method NoExtensionMethods::AsFunc
+
+  .method private hidebysig static !!T  Return<T>(!!T 'value') cil managed
+  {
+    .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() = ( 01 00 00 00 ) 
+    // Code size       7 (0x7)
+    .maxstack  1
+    .locals init (!!T V_0)
+    IL_0000:  nop
+    IL_0001:  ldarg.0
+    IL_0002:  stloc.0
+    IL_0003:  br.s       IL_0005
+
+    IL_0005:  ldloc.0
+    IL_0006:  ret
+  } // end of method NoExtensionMethods::Return
+
+  .method assembly hidebysig static class [mscorlib]System.Func`2<int32,int32> 
+          ExtensionMethodAsStaticFunc() cil managed
+  {
+    // Code size       18 (0x12)
+    .maxstack  2
+    .locals init (class [mscorlib]System.Func`2<int32,int32> V_0)
+    IL_0000:  nop
+    IL_0001:  ldnull
+    IL_0002:  ldftn      !!0 ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods::Return<int32>(!!0)
+    IL_0008:  newobj     instance void class [mscorlib]System.Func`2<int32,int32>::.ctor(object,
+                                                                                         native int)
+    IL_000d:  stloc.0
+    IL_000e:  br.s       IL_0010
+
+    IL_0010:  ldloc.0
+    IL_0011:  ret
+  } // end of method NoExtensionMethods::ExtensionMethodAsStaticFunc
+
+  .method assembly hidebysig static class [mscorlib]System.Func`1<object> 
+          ExtensionMethodBoundToNull() cil managed
+  {
+    // Code size       18 (0x12)
+    .maxstack  2
+    .locals init (class [mscorlib]System.Func`1<object> V_0)
+    IL_0000:  nop
+    IL_0001:  ldnull
+    IL_0002:  ldftn      !!0 ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods::Return<object>(!!0)
+    IL_0008:  newobj     instance void class [mscorlib]System.Func`1<object>::.ctor(object,
+                                                                                    native int)
+    IL_000d:  stloc.0
+    IL_000e:  br.s       IL_0010
+
+    IL_0010:  ldloc.0
+    IL_0011:  ret
+  } // end of method NoExtensionMethods::ExtensionMethodBoundToNull
+
+} // end of class ICSharpCode.Decompiler.Tests.TestCases.Ugly.NoExtensionMethods
+
+
+// =============================================================
+
+// *********** DISASSEMBLY COMPLETE ***********************

ICSharpCode.Decompiler.Tests/UglyTestRunner.cs

@@ -83,6 +83,14 @@ namespace ICSharpCode.Decompiler.Tests
 			});
 		}
 
+		[Test]
+		public void NoExtensionMethods([ValueSource("roslynOnlyOptions")] CompilerOptions cscOptions)
+		{
+			RunForLibrary(cscOptions: cscOptions, decompilerSettings: new DecompilerSettings {
+				ExtensionMethods = false
+			});
+		}
+
 		void RunForLibrary([CallerMemberName] string testName = null, AssemblerOptions asmOptions = AssemblerOptions.None, CompilerOptions cscOptions = CompilerOptions.None, DecompilerSettings decompilerSettings = null)
 		{
 			Run(testName, asmOptions | AssemblerOptions.Library, cscOptions | CompilerOptions.Library, decompilerSettings);

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -105,6 +105,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				new SwitchOnStringTransform(),
 				new SwitchOnNullableTransform(),
 				new SplitVariables(), // split variables once again, because SwitchOnNullableTransform eliminates ldloca 
+				new IntroduceRefReadOnlyModifierOnLocals(),
 				new BlockILTransform { // per-block transforms
 					PostOrderTransforms = {
 						// Even though it's a post-order block-transform as most other transforms,

ICSharpCode.Decompiler/CSharp/CallBuilder.cs

@@ -1235,7 +1235,38 @@ namespace ICSharpCode.Decompiler.CSharp
 				default:
 					throw new ArgumentException($"Unknown instruction type: {func.OpCode}");
 			}
+			if (CanUseDelegateConstruction(method, thisArg, inst.Method.DeclaringType.GetDelegateInvokeMethod())) {
 				return HandleDelegateConstruction(inst.Method.DeclaringType, method, expectedTargetDetails, thisArg, inst);
+			} else {
+				var argumentList = BuildArgumentList(expectedTargetDetails, null, inst.Method,
+					0, inst.Arguments, null);
+				return HandleConstructorCall(new ExpectedTargetDetails { CallOpCode = OpCode.NewObj }, null, inst.Method, argumentList).WithILInstruction(inst);
+			}
+		}
+
+		private bool CanUseDelegateConstruction(IMethod targetMethod, ILInstruction thisArg, IMethod invokeMethod)
+		{
+			if (targetMethod.IsStatic) {
+				// If the invoke method is known, we can compare the parameter counts to figure out whether the
+				// delegate is static or binds the first argument
+				if (invokeMethod != null) {
+					if (invokeMethod.Parameters.Count == targetMethod.Parameters.Count) {
+						return thisArg.MatchLdNull();
+					} else if (targetMethod.IsExtensionMethod && invokeMethod.Parameters.Count == targetMethod.Parameters.Count - 1) {
+						return true;
+					} else {
+						return false;
+					}
+				} else {
+					// delegate type unknown:
+					return thisArg.MatchLdNull() || targetMethod.IsExtensionMethod;
+				}
+			} else {
+				// targetMethod is instance method
+				if (invokeMethod != null && invokeMethod.Parameters.Count != targetMethod.Parameters.Count)
+					return false;
+				return true;
+			}
 		}
 
 		internal TranslatedExpression Build(LdVirtDelegate inst)
@@ -1243,9 +1274,15 @@ namespace ICSharpCode.Decompiler.CSharp
 			return HandleDelegateConstruction(inst.Type, inst.Method, new ExpectedTargetDetails { CallOpCode = OpCode.CallVirt }, inst.Argument, inst);
 		}
 
-		TranslatedExpression HandleDelegateConstruction(IType delegateType, IMethod method, ExpectedTargetDetails expectedTargetDetails, ILInstruction thisArg, ILInstruction inst)
+		internal ExpressionWithResolveResult BuildMethodReference(IMethod method, bool isVirtual)
+		{
+			var expr = BuildDelegateReference(method, invokeMethod: null, new ExpectedTargetDetails { CallOpCode = isVirtual ? OpCode.CallVirt : OpCode.Call }, thisArg: null);
+			expr.Expression.RemoveAnnotations<ResolveResult>();
+			return expr.Expression.WithRR(new MemberResolveResult(null, method));
+		}
+
+		ExpressionWithResolveResult BuildDelegateReference(IMethod method, IMethod invokeMethod, ExpectedTargetDetails expectedTargetDetails, ILInstruction thisArg)
 		{
-			var invokeMethod = delegateType.GetDelegateInvokeMethod();
 			TranslatedExpression target;
 			IType targetType;
 			bool requireTarget;
@@ -1331,27 +1368,32 @@ namespace ICSharpCode.Decompiler.CSharp
 				}
 			}
 			requireTarget = !method.IsLocalFunction && (step & 1) != 0;
-			Expression targetExpression;
+			ExpressionWithResolveResult targetExpression;
 			Debug.Assert(result != null);
 			if (requireTarget) {
 				Debug.Assert(target.Expression != null);
 				var mre = new MemberReferenceExpression(target, methodName);
 				if ((step & 2) != 0)
 					mre.TypeArguments.AddRange(method.TypeArguments.Select(expressionBuilder.ConvertType));
-				mre.WithRR(result);
-				targetExpression = mre;
+				targetExpression = mre.WithRR(result);
 			} else {
 				var ide = new IdentifierExpression(methodName);
 				if ((step & 2) != 0)
 					ide.TypeArguments.AddRange(method.TypeArguments.Select(expressionBuilder.ConvertType));
-				ide.WithRR(result);
-				targetExpression = ide;
+				targetExpression = ide.WithRR(result);
+			}
+			return targetExpression;
 		}
+
+		TranslatedExpression HandleDelegateConstruction(IType delegateType, IMethod method, ExpectedTargetDetails expectedTargetDetails, ILInstruction thisArg, ILInstruction inst)
+		{
+			var invokeMethod = delegateType.GetDelegateInvokeMethod();
+			var targetExpression = BuildDelegateReference(method, invokeMethod, expectedTargetDetails, thisArg);
 			var oce = new ObjectCreateExpression(expressionBuilder.ConvertType(delegateType), targetExpression)
 				.WithILInstruction(inst)
 				.WithRR(new ConversionResolveResult(
 					delegateType,
-					result,
+					targetExpression.ResolveResult,
 					Conversion.MethodGroupConversion(method, expectedTargetDetails.CallOpCode == OpCode.CallVirt, false)));
 			return oce;
 		}

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -1409,7 +1409,8 @@ namespace ICSharpCode.Decompiler.CSharp
 			if (UserDefinedCompoundAssign.IsStringConcat(inst.Method)) {
 				Debug.Assert(inst.Method.Parameters.Count == 2);
 				var value = Translate(inst.Value).ConvertTo(inst.Method.Parameters[1].Type, this, allowImplicitConversion: true);
-				return new AssignmentExpression(target, AssignmentOperatorType.Add, value)
+				var valueExpr = ReplaceMethodCallsWithOperators.RemoveRedundantToStringInConcat(value, inst.Method, isLastArgument: true).Detach();
+				return new AssignmentExpression(target, AssignmentOperatorType.Add, valueExpr)
 					.WithILInstruction(inst)
 					.WithRR(new OperatorResolveResult(inst.Method.ReturnType, ExpressionType.AddAssign, inst.Method, inst.IsLifted, new[] { target.ResolveResult, value.ResolveResult }));
 			} else if (inst.Method.Parameters.Count == 2) {
@@ -3134,6 +3135,22 @@ namespace ICSharpCode.Decompiler.CSharp
 				.WithRR(new OperatorResolveResult(SpecialType.Dynamic, inst.Operation, new[] { target.ResolveResult, value.ResolveResult }));
 		}
 
+		protected internal override TranslatedExpression VisitLdFtn(LdFtn inst, TranslationContext context)
+		{
+			ExpressionWithResolveResult delegateRef = new CallBuilder(this, typeSystem, settings).BuildMethodReference(inst.Method, isVirtual: false);
+			return new InvocationExpression(new IdentifierExpression("__ldftn"), delegateRef)
+				.WithRR(new ResolveResult(compilation.FindType(KnownTypeCode.IntPtr)))
+				.WithILInstruction(inst);
+		}
+
+		protected internal override TranslatedExpression VisitLdVirtFtn(LdVirtFtn inst, TranslationContext context)
+		{
+			ExpressionWithResolveResult delegateRef = new CallBuilder(this, typeSystem, settings).BuildMethodReference(inst.Method, isVirtual: true);
+			return new InvocationExpression(new IdentifierExpression("__ldvirtftn"), delegateRef)
+				.WithRR(new ResolveResult(compilation.FindType(KnownTypeCode.IntPtr)))
+				.WithILInstruction(inst);
+		}
+
 		protected internal override TranslatedExpression VisitInvalidBranch(InvalidBranch inst, TranslationContext context)
 		{
 			string message = "Error";

ICSharpCode.Decompiler/CSharp/SequencePointBuilder.cs

@@ -300,7 +300,7 @@ namespace ICSharpCode.Decompiler.CSharp
 					if (sequencePoint.Offset < pos) {
 						// overlapping sequence point?
 						// delete previous sequence points that are after sequencePoint.Offset
-						while (newList.Count > 0 && newList.Last().EndOffset > pos) {
+						while (newList.Count > 0 && newList.Last().EndOffset > sequencePoint.Offset) {
 							var last = newList.Last();
 							if (last.Offset >= sequencePoint.Offset) {
 								newList.RemoveAt(newList.Count - 1);

ICSharpCode.Decompiler/CSharp/Syntax/TypeSystemAstBuilder.cs

@@ -1522,6 +1522,8 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			Accessor decl = new Accessor();
 			if (this.ShowAccessibility && accessor.Accessibility != ownerAccessibility)
 				decl.Modifiers = ModifierFromAccessibility(accessor.Accessibility);
+			if (accessor.ThisIsRefReadOnly && accessor.DeclaringTypeDefinition?.IsReadOnly == false)
+				decl.Modifiers |= Modifiers.Readonly;
 			if (ShowAttributes) {
 				decl.Attributes.AddRange(ConvertAttributes(accessor.GetAttributes()));
 				decl.Attributes.AddRange(ConvertAttributes(accessor.GetReturnTypeAttributes(), "return"));
@@ -1551,9 +1553,18 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			decl.Getter = ConvertAccessor(property.Getter, property.Accessibility, false);
 			decl.Setter = ConvertAccessor(property.Setter, property.Accessibility, true);
 			decl.PrivateImplementationType = GetExplicitInterfaceType (property);
+			MergeReadOnlyModifiers(decl, decl.Getter, decl.Setter);
 			return decl;
 		}
 		
+		static void MergeReadOnlyModifiers(EntityDeclaration decl, Accessor accessor1, Accessor accessor2)
+		{
+			if (accessor1.HasModifier(Modifiers.Readonly) && accessor2.HasModifier(Modifiers.Readonly)) {
+				accessor1.Modifiers &= ~Modifiers.Readonly;
+				accessor2.Modifiers &= ~Modifiers.Readonly;
+				decl.Modifiers |= Modifiers.Readonly;
+			}
+		}
 		IndexerDeclaration ConvertIndexer(IProperty indexer)
 		{
 			IndexerDeclaration decl = new IndexerDeclaration();
@@ -1571,6 +1582,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			decl.Getter = ConvertAccessor(indexer.Getter, indexer.Accessibility, false);
 			decl.Setter = ConvertAccessor(indexer.Setter, indexer.Accessibility, true);
 			decl.PrivateImplementationType = GetExplicitInterfaceType (indexer);
+			MergeReadOnlyModifiers(decl, decl.Getter, decl.Setter);
 			return decl;
 		}
 		
@@ -1590,6 +1602,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				decl.AddAccessor    = ConvertAccessor(ev.AddAccessor, ev.Accessibility, true);
 				decl.RemoveAccessor = ConvertAccessor(ev.RemoveAccessor, ev.Accessibility, true);
 				decl.PrivateImplementationType = GetExplicitInterfaceType (ev);
+				MergeReadOnlyModifiers(decl, decl.AddAccessor, decl.RemoveAccessor);
 				return decl;
 			} else {
 				EventDeclaration decl = new EventDeclaration();
@@ -1728,8 +1741,11 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		bool NeedsAccessibility(IMember member)
 		{
 			var declaringType = member.DeclaringType;
-			if ((declaringType != null && declaringType.Kind == TypeKind.Interface) || member.IsExplicitInterfaceImplementation)
+			if (member.IsExplicitInterfaceImplementation)
 				return false;
+			if (declaringType != null && declaringType.Kind == TypeKind.Interface) {
+				return member.Accessibility != Accessibility.Public;
+			}
 			switch (member.SymbolKind) {
 				case SymbolKind.Constructor:
 					return !member.IsStatic;
@@ -1751,14 +1767,21 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 					m |= Modifiers.Static;
 				} else {
 					var declaringType = member.DeclaringType;
-					if (member.IsAbstract && declaringType != null && declaringType.Kind != TypeKind.Interface)
+					if (declaringType.Kind == TypeKind.Interface) {
+						if (!member.IsVirtual && !member.IsAbstract && !member.IsOverride && member.Accessibility != Accessibility.Private)
+							m |= Modifiers.Sealed;
+					} else {
+						if (member.IsAbstract)
 							m |= Modifiers.Abstract;
-					if (member.IsOverride)
-						m |= Modifiers.Override;
-					if (member.IsVirtual && !member.IsAbstract && !member.IsOverride && declaringType.Kind != TypeKind.Interface)
+						else if (member.IsVirtual && !member.IsOverride)
 							m |= Modifiers.Virtual;
-					if (member.IsSealed)
+					}
+					if (member.IsOverride && !member.IsExplicitInterfaceImplementation)
+						m |= Modifiers.Override;
+					if (member.IsSealed && !member.IsExplicitInterfaceImplementation)
 						m |= Modifiers.Sealed;
+					if (member is IMethod method && method.ThisIsRefReadOnly && method.DeclaringTypeDefinition?.IsReadOnly == false)
+						m |= Modifiers.Readonly;
 				}
 			}
 			return m;

ICSharpCode.Decompiler/CSharp/Transforms/DeclareVariables.cs

@@ -447,6 +447,9 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					} else {
 						type = context.TypeSystemAstBuilder.ConvertType(v.Type);
 					}
+					if (v.ILVariable.IsRefReadOnly && type is ComposedType composedType && composedType.HasRefSpecifier) {
+						composedType.HasReadOnlySpecifier = true;
+					}
 					var vds = new VariableDeclarationStatement(type, v.Name, assignment.Right.Detach());
 					var init = vds.Variables.Single();
 					init.AddAnnotation(assignment.Left.GetResolveResult());

ICSharpCode.Decompiler/CSharp/Transforms/PatternStatementTransform.cs

@@ -571,11 +571,14 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			}
 			if (field == null)
 				return null;
+			if (propertyDeclaration.Setter.HasModifier(Modifiers.Readonly))
+				return null;
 			if (field.IsCompilerGenerated() && field.DeclaringTypeDefinition == property.DeclaringTypeDefinition) {
 				RemoveCompilerGeneratedAttribute(propertyDeclaration.Getter.Attributes);
 				RemoveCompilerGeneratedAttribute(propertyDeclaration.Setter.Attributes);
 				propertyDeclaration.Getter.Body = null;
 				propertyDeclaration.Setter.Body = null;
+				propertyDeclaration.Getter.Modifiers &= ~Modifiers.Readonly;
 
 				// Add C# 7.3 attributes on backing field:
 				var attributes = field.GetAttributes()

ICSharpCode.Decompiler/CSharp/Transforms/ReplaceMethodCallsWithOperators.cs

@@ -23,7 +23,9 @@ using System.Reflection;
 using System.Text;
 using ICSharpCode.Decompiler.CSharp.Syntax;
 using ICSharpCode.Decompiler.CSharp.Syntax.PatternMatching;
+using ICSharpCode.Decompiler.Semantics;
 using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.Decompiler.Util;
 
 namespace ICSharpCode.Decompiler.CSharp.Transforms
 {
@@ -56,11 +58,19 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			var arguments = invocationExpression.Arguments.ToArray();
 
 			// Reduce "String.Concat(a, b)" to "a + b"
-			if (method.Name == "Concat" && method.DeclaringType.FullName == "System.String" && CheckArgumentsForStringConcat(arguments)) {
-				invocationExpression.Arguments.Clear(); // detach arguments from invocationExpression
-				Expression expr = arguments[0];
+			if (IsStringConcat(method) && CheckArgumentsForStringConcat(arguments)) {
+				bool isInExpressionTree = invocationExpression.Ancestors.OfType<LambdaExpression>().Any(
+					lambda => lambda.Annotation<IL.ILFunction>()?.Kind == IL.ILFunctionKind.ExpressionTree);
+				Expression expr = arguments[0].Detach();
+				if (!isInExpressionTree) {
+					expr = RemoveRedundantToStringInConcat(expr, method, isLastArgument: false).Detach();
+				}
 				for (int i = 1; i < arguments.Length; i++) {
-					expr = new BinaryOperatorExpression(expr, BinaryOperatorType.Add, arguments[i].UnwrapInDirectionExpression());
+					var arg = arguments[i].Detach();
+					if (!isInExpressionTree) {
+						arg = RemoveRedundantToStringInConcat(arg, method, isLastArgument: i == arguments.Length - 1).Detach();
+					}
+					expr = new BinaryOperatorExpression(expr, BinaryOperatorType.Add, arg);
 				}
 				expr.CopyAnnotationsFrom(invocationExpression);
 				invocationExpression.ReplaceWith(expr);
@@ -174,9 +184,135 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			if (arguments.Length < 2)
 				return false;
 
-			return !arguments.Any(arg => arg is NamedArgumentExpression) &&
-				(arguments[0].GetResolveResult().Type.IsKnownType(KnownTypeCode.String) ||
-				arguments[1].GetResolveResult().Type.IsKnownType(KnownTypeCode.String));
+			if (arguments.Any(arg => arg is NamedArgumentExpression))
+				return false;
+
+			// The evaluation order when the object.ToString() calls happen is a mess:
+			// The C# spec says the evaluation for order for each individual string + should be:
+			//   * evaluate left argument
+			//   * evaluate right argument
+			//   * call ToString() on object argument
+			// What actually happens pre-VS2019.3:
+			//   * evaluate all arguments in chain of + operators from left to right
+			//   * call ToString() on all object arguments from left to right
+			// What happens in VS2019.3:
+			//   * for each argument in chain of + operators fom left to right:
+			//       * evaluate argument
+			//       * call ToString() on object argument
+			// See https://github.com/dotnet/roslyn/issues/38641 for details.
+			// To ensure the decompiled code's behavior matches the original IL behavior,
+			// no matter which compiler is used to recompile it, we require that all
+			// implicit ToString() calls except for the last are free of side effects.
+			foreach (var arg in arguments.SkipLast(1)) {
+				if (!ToStringIsKnownEffectFree(arg.GetResolveResult().Type)) {
+					return false;
+				}
+			}
+			foreach (var arg in arguments) {
+				if (arg.GetResolveResult() is InvocationResolveResult rr && IsStringConcat(rr.Member)) {
+					// Roslyn + mcs also flatten nested string.Concat() invocations within a operator+ use,
+					// which causes it to use the incorrect evaluation order despite the code using an
+					// explicit string.Concat() call.
+					// This problem is avoided if the outer call remains string.Concat() as well.
+					return false;
+				}
+			}
+
+			// One of the first two arguments must be string, otherwise the + operator
+			// won't resolve to a string concatenation.
+			return arguments[0].GetResolveResult().Type.IsKnownType(KnownTypeCode.String)
+				|| arguments[1].GetResolveResult().Type.IsKnownType(KnownTypeCode.String);
+		}
+
+		private bool IsStringConcat(IParameterizedMember member)
+		{
+			return member is IMethod method
+				&& method.Name == "Concat"
+				&& method.DeclaringType.IsKnownType(KnownTypeCode.String);
+		}
+
+		static readonly Pattern ToStringCallPattern = new Choice {
+			// target.ToString()
+			new InvocationExpression(new MemberReferenceExpression(new AnyNode("target"), "ToString")).WithName("call"),
+			// target?.ToString()
+			new UnaryOperatorExpression(
+				UnaryOperatorType.NullConditionalRewrap,
+				new InvocationExpression(
+					new MemberReferenceExpression(
+						new UnaryOperatorExpression(UnaryOperatorType.NullConditional, new AnyNode("target")),
+						"ToString")
+				).WithName("call")
+			).WithName("nullConditional")
+		};
+
+		internal static Expression RemoveRedundantToStringInConcat(Expression expr, IMethod concatMethod, bool isLastArgument)
+		{
+			var m = ToStringCallPattern.Match(expr);
+			if (!m.Success)
+				return expr;
+
+			if (!concatMethod.Parameters.All(IsStringParameter)) {
+				// If we're using a string.Concat() overload involving object parameters,
+				// string.Concat() itself already calls ToString() so the C# compiler shouldn't
+				// generate additional ToString() calls in this case.
+				return expr;
+			}
+			var toStringMethod = m.Get<Expression>("call").Single().GetSymbol() as IMethod;
+			var target = m.Get<Expression>("target").Single();
+			var type = target.GetResolveResult().Type;
+			if (!(isLastArgument || ToStringIsKnownEffectFree(type))) {
+				// ToString() order of evaluation matters, see CheckArgumentsForStringConcat().
+				return expr;
+			}
+			if (type.IsReferenceType != false && !m.Has("nullConditional")) {
+				// ToString() might throw NullReferenceException, but the builtin operator+ doesn't.
+				return expr;
+			}
+			if (!ToStringIsKnownEffectFree(type) && toStringMethod != null && IL.Transforms.ILInlining.MethodRequiresCopyForReadonlyLValue(toStringMethod)) {
+				// ToString() on a struct may mutate the struct.
+				// For operator+ the C# compiler creates a temporary copy before implicitly calling ToString(),
+				// whereas an explicit ToString() call would mutate the original lvalue.
+				// So we can't remove the compiler-generated ToString() call in cases where this might make a difference.
+				return expr;
+			}
+
+			// All checks succeeded, we can eliminate the ToString() call.
+			// The C# compiler will generate an equivalent call if the code is recompiled.
+			return target;
+
+			bool IsStringParameter(IParameter p)
+			{
+				IType ty = p.Type;
+				if (p.IsParams && ty.Kind == TypeKind.Array)
+					ty = ((ArrayType)ty).ElementType;
+				return ty.IsKnownType(KnownTypeCode.String);
+			}
+		}
+
+		static bool ToStringIsKnownEffectFree(IType type)
+		{
+			type = NullableType.GetUnderlyingType(type);
+			switch (type.GetDefinition()?.KnownTypeCode) {
+				case KnownTypeCode.Boolean:
+				case KnownTypeCode.Char:
+				case KnownTypeCode.SByte:
+				case KnownTypeCode.Byte:
+				case KnownTypeCode.Int16:
+				case KnownTypeCode.UInt16:
+				case KnownTypeCode.Int32:
+				case KnownTypeCode.UInt32:
+				case KnownTypeCode.Int64:
+				case KnownTypeCode.UInt64:
+				case KnownTypeCode.Single:
+				case KnownTypeCode.Double:
+				case KnownTypeCode.Decimal:
+				case KnownTypeCode.IntPtr:
+				case KnownTypeCode.UIntPtr:
+				case KnownTypeCode.String:
+					return true;
+				default:
+					return false;
+			}
 		}
 
 		static BinaryOperatorType? GetBinaryOperatorTypeFromMetadataName(string name)

ICSharpCode.Decompiler/CSharp/TranslatedExpression.cs

@@ -283,10 +283,9 @@ namespace ICSharpCode.Decompiler.CSharp
 					UnwrapChild(uoe.Expression).ConvertTo(targetType, expressionBuilder, checkForOverflow, allowImplicitConversion)
 				).WithRR(new ResolveResult(targetType)).WithoutILInstruction();
 			}
-			bool isLifted = type.IsKnownType(KnownTypeCode.NullableOfT) && targetType.IsKnownType(KnownTypeCode.NullableOfT);
-			IType utype = isLifted ? NullableType.GetUnderlyingType(type) : type;
-			IType targetUType = isLifted ? NullableType.GetUnderlyingType(targetType) : targetType;
-			if (type.IsKnownType(KnownTypeCode.Boolean) && targetType.GetStackType().IsIntegerType()) {
+			IType utype = NullableType.GetUnderlyingType(type);
+			IType targetUType = NullableType.GetUnderlyingType(targetType);
+			if (type.IsKnownType(KnownTypeCode.Boolean) && targetUType.GetStackType().IsIntegerType()) {
 				// convert from boolean to integer (or enum)
 				return new ConditionalExpression(
 					this.Expression,
@@ -318,7 +317,7 @@ namespace ICSharpCode.Decompiler.CSharp
 						.ConvertTo(targetType, expressionBuilder, checkForOverflow);
 				}
 			}
-			if (targetType.IsKnownType(KnownTypeCode.IntPtr)) { // Conversion to IntPtr
+			if (targetUType.IsKnownType(KnownTypeCode.IntPtr)) { // Conversion to IntPtr
 				if (type.IsKnownType(KnownTypeCode.Int32)) {
 					// normal casts work for int (both in checked and unchecked context)
 				} else if (checkForOverflow) {
@@ -336,7 +335,7 @@ namespace ICSharpCode.Decompiler.CSharp
 							.ConvertTo(targetType, expressionBuilder, checkForOverflow);
 					}
 				}
-			} else if (targetType.IsKnownType(KnownTypeCode.UIntPtr)) { // Conversion to UIntPtr
+			} else if (targetUType.IsKnownType(KnownTypeCode.UIntPtr)) { // Conversion to UIntPtr
 				if (type.IsKnownType(KnownTypeCode.UInt32) || type.Kind == TypeKind.Pointer) {
 					// normal casts work for uint and pointers (both in checked and unchecked context)
 				} else if (checkForOverflow) {
@@ -359,14 +358,14 @@ namespace ICSharpCode.Decompiler.CSharp
 				// -> convert via underlying type
 				return this.ConvertTo(type.GetEnumUnderlyingType(), expressionBuilder, checkForOverflow)
 					.ConvertTo(targetType, expressionBuilder, checkForOverflow);
-			} else if (targetType.Kind == TypeKind.Enum && type.Kind == TypeKind.Pointer) {
+			} else if (targetUType.Kind == TypeKind.Enum && type.Kind == TypeKind.Pointer) {
 				// pointer to enum: C# doesn't allow such casts
 				// -> convert via underlying type
-				return this.ConvertTo(targetType.GetEnumUnderlyingType(), expressionBuilder, checkForOverflow)
+				return this.ConvertTo(targetUType.GetEnumUnderlyingType(), expressionBuilder, checkForOverflow)
 					.ConvertTo(targetType, expressionBuilder, checkForOverflow);
 			}
 			if (targetType.Kind == TypeKind.Pointer && type.IsKnownType(KnownTypeCode.Char)
-			   || targetType.IsKnownType(KnownTypeCode.Char) && type.Kind == TypeKind.Pointer) {
+			   || targetUType.IsKnownType(KnownTypeCode.Char) && type.Kind == TypeKind.Pointer) {
 				// char <-> pointer: C# doesn't allow such casts
 				// -> convert via ushort
 				return this.ConvertTo(compilation.FindType(KnownTypeCode.UInt16), expressionBuilder, checkForOverflow)
@@ -418,6 +417,17 @@ namespace ICSharpCode.Decompiler.CSharp
 					.WithoutILInstruction()
 					.WithRR(new ByReferenceResolveResult(elementRR, ReferenceKind.Ref));
 			}
+			if (this.ResolveResult.IsCompileTimeConstant && this.ResolveResult.ConstantValue != null
+				&& NullableType.IsNullable(targetType) && !utype.Equals(targetUType))
+			{
+				// Casts like `(uint?)-1` are only valid in an explicitly unchecked context, but we
+				// don't have logic to ensure such a context (usually we emit into an implicitly unchecked context).
+				// This only applies with constants as input (int->uint? is fine in implicitly unchecked context).
+				// We use an intermediate cast to the nullable's underlying type, which results
+				// in a constant conversion, so the final output will be something like `(uint?)uint.MaxValue`
+				return ConvertTo(targetUType, expressionBuilder, checkForOverflow, allowImplicitConversion: false)
+					.ConvertTo(targetType, expressionBuilder, checkForOverflow, allowImplicitConversion);
+			}
 			var rr = expressionBuilder.resolver.WithCheckForOverflow(checkForOverflow).ResolveCast(targetType, ResolveResult);
 			if (rr.IsCompileTimeConstant && !rr.IsError) {
 				return expressionBuilder.ConvertConstantValue(rr, allowImplicitConversion)

ICSharpCode.Decompiler/DebugInfo/SequencePoint.cs

@@ -17,12 +17,14 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System;
+using System.Diagnostics;
 
 namespace ICSharpCode.Decompiler.DebugInfo
 {
 	/// <summary>
 	/// A sequence point read from a PDB file or produced by the decompiler.
 	/// </summary>
+	[DebuggerDisplay("SequencePoint IL_{Offset,h}-IL_{EndOffset,h}, {StartLine}:{StartColumn}-{EndLine}:{EndColumn}, IsHidden={IsHidden}")]
 	public struct SequencePoint
 	{
 		/// <summary>

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -107,12 +107,13 @@ namespace ICSharpCode.Decompiler
 			}
 			if (languageVersion < CSharp.LanguageVersion.CSharp8_0) {
 				nullableReferenceTypes = false;
+				readOnlyMethods = false;
 			}
 		}
 
 		public CSharp.LanguageVersion GetMinimumRequiredVersion()
 		{
-			if (nullableReferenceTypes)
+			if (nullableReferenceTypes || readOnlyMethods)
 				return CSharp.LanguageVersion.CSharp8_0;
 			if (introduceUnmanagedConstraint || tupleComparisons || stackAllocInitializers)
 				return CSharp.LanguageVersion.CSharp7_3;
@@ -842,6 +843,20 @@ namespace ICSharpCode.Decompiler
 			}
 		}
 
+		bool readOnlyMethods = true;
+
+		[Category("C# 8.0 / VS 2019")]
+		[Description("DecompilerSettings.IsReadOnlyAttributeShouldBeReplacedWithReadonlyInModifiersOnStructsParameters")]
+		public bool ReadOnlyMethods {
+			get { return readOnlyMethods; }
+			set {
+				if (readOnlyMethods != value) {
+					readOnlyMethods = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		bool introduceUnmanagedConstraint = true;
 
 		/// <summary>

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -328,6 +328,7 @@
     <Compile Include="IL\Transforms\HighLevelLoopTransform.cs" />
     <Compile Include="IL\Transforms\NamedArgumentTransform.cs" />
     <Compile Include="IL\Transforms\IntroduceDynamicTypeOnLocals.cs" />
+    <Compile Include="IL\Transforms\IntroduceRefReadOnlyModifierOnLocals.cs" />
     <Compile Include="IL\Transforms\NullPropagationTransform.cs" />
     <Compile Include="IL\Transforms\ProxyCallReplacer.cs" />
     <Compile Include="IL\Instructions\StringToInt.cs" />

ICSharpCode.Decompiler/IL/ControlFlow/AsyncAwaitDecompiler.cs

@@ -85,6 +85,7 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 		TryCatch mainTryCatch;
 		Block setResultAndExitBlock; // block that is jumped to for return statements
 		int finalState;       // final state after the setResultAndExitBlock
+		bool finalStateKnown;
 		ILVariable resultVar; // the variable that gets returned by the setResultAndExitBlock
 		ILVariable doFinallyBodies;
 
@@ -352,7 +353,7 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 			moveNextFunction = YieldReturnDecompiler.CreateILAst(moveNextMethod, context);
 			if (!(moveNextFunction.Body is BlockContainer blockContainer))
 				throw new SymbolicAnalysisFailedException();
-			if (blockContainer.Blocks.Count != 2)
+			if (blockContainer.Blocks.Count != 2 && blockContainer.Blocks.Count != 1)
 				throw new SymbolicAnalysisFailedException();
 			if (blockContainer.EntryPoint.IncomingEdgeCount != 1)
 				throw new SymbolicAnalysisFailedException();
@@ -389,7 +390,14 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 				doFinallyBodies = initDoFinallyBodies.Variable;
 			}
 
-			setResultAndExitBlock = blockContainer.Blocks[1];
+			setResultAndExitBlock = blockContainer.Blocks.ElementAtOrDefault(1);
+			if (setResultAndExitBlock == null) {
+				// This block can be absent if the function never exits normally,
+				// but always throws an exception/loops infinitely.
+				resultVar = null;
+				finalStateKnown = false; // final state will be detected in ValidateCatchBlock() instead
+				return;
+			}
 			// stobj System.Int32(ldflda [Field ICSharpCode.Decompiler.Tests.TestCases.Pretty.Async+<SimpleBoolTaskMethod>d__7.<>1__state](ldloc this), ldc.i4 -2)
 			// call SetResult(ldflda [Field ICSharpCode.Decompiler.Tests.TestCases.Pretty.Async+<SimpleBoolTaskMethod>d__7.<>t__builder](ldloc this), ldloc result)
 			// leave IL_0000
@@ -397,6 +405,7 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 				throw new SymbolicAnalysisFailedException();
 			if (!MatchStateAssignment(setResultAndExitBlock.Instructions[0], out finalState))
 				throw new SymbolicAnalysisFailedException();
+			finalStateKnown = true;
 			if (!MatchCall(setResultAndExitBlock.Instructions[1], "SetResult", out var args))
 				throw new SymbolicAnalysisFailedException();
 			if (!IsBuilderFieldOnThis(args[0]))
@@ -442,8 +451,15 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 			if (!stloc.Value.MatchLdLoc(handler.Variable))
 				throw new SymbolicAnalysisFailedException();
 			// stfld <>1__state(ldloc this, ldc.i4 -2)
-			if (!MatchStateAssignment(catchBlock.Instructions[1], out int newState) || newState != finalState)
+			if (!MatchStateAssignment(catchBlock.Instructions[1], out int newState))
 				throw new SymbolicAnalysisFailedException();
+			if (finalStateKnown) {
+				if (newState != finalState)
+					throw new SymbolicAnalysisFailedException();
+			} else {
+				finalState = newState;
+				finalStateKnown = true;
+			}
 			// call SetException(ldfld <>t__builder(ldloc this), ldloc exception)
 			if (!MatchCall(catchBlock.Instructions[2], "SetException", out var args))
 				throw new SymbolicAnalysisFailedException();

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -190,12 +190,15 @@ namespace ICSharpCode.Decompiler.IL
 					// and needs to be converted into a normally usable type.
 					declaringType = new ParameterizedType(declaringType, declaringType.TypeParameters);
 				}
-				parameterVariables[paramIndex++] = CreateILVariable(-1, declaringType, "this");
+				ILVariable ilVar = CreateILVariable(-1, declaringType, "this");
+				ilVar.IsRefReadOnly = method.ThisIsRefReadOnly;
+				parameterVariables[paramIndex++] = ilVar;
 			}
 			while (paramIndex < parameterVariables.Length) {
-				IType type = method.Parameters[paramIndex - offset].Type;
-				string name = method.Parameters[paramIndex - offset].Name;
-				parameterVariables[paramIndex] = CreateILVariable(paramIndex - offset, type, name);
+				IParameter parameter = method.Parameters[paramIndex - offset];
+				ILVariable ilVar = CreateILVariable(paramIndex - offset, parameter.Type, parameter.Name);
+				ilVar.IsRefReadOnly = parameter.IsIn;
+				parameterVariables[paramIndex] = ilVar;
 				paramIndex++;
 			}
 			Debug.Assert(paramIndex == parameterVariables.Length);

ICSharpCode.Decompiler/IL/ILVariable.cs

@@ -132,6 +132,11 @@ namespace ICSharpCode.Decompiler.IL
 			}
 		}
 
+		/// <summary>
+		/// This variable is either a C# 7 'in' parameter or must be declared as 'ref readonly'.
+		/// </summary>
+		public bool IsRefReadOnly { get; internal set; }
+		
 		/// <summary>
 		/// The index of the local variable or parameter (depending on Kind)
 		/// 
@@ -371,6 +376,9 @@ namespace ICSharpCode.Decompiler.IL
 		
 		internal void WriteDefinitionTo(ITextOutput output)
 		{
+			if (IsRefReadOnly) {
+				output.Write("readonly ");
+			}
 			switch (Kind) {
 				case VariableKind.Local:
 					output.Write("local ");

ICSharpCode.Decompiler/IL/Transforms/CopyPropagation.cs

@@ -18,6 +18,7 @@
 
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.Decompiler.Util;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 
@@ -31,7 +32,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 	///    then we can replace the variable with the argument.
 	/// 2) assignments of address-loading instructions to local variables
 	/// </summary>
-	public class CopyPropagation : IBlockTransform, IILTransform
+	public class CopyPropagation : IILTransform
 	{
 		public static void Propagate(StLoc store, ILTransformContext context)
 		{
@@ -41,26 +42,25 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			DoPropagate(store.Variable, store.Value, block, ref i, context);
 		}
 
-		public void Run(Block block, BlockTransformContext context)
-		{
-			RunOnBlock(block, context);
-		}
-
 		public void Run(ILFunction function, ILTransformContext context)
 		{
+			var splitVariables = new HashSet<ILVariable>(ILVariableEqualityComparer.Instance);
+			foreach (var g in function.Variables.GroupBy(v => v, ILVariableEqualityComparer.Instance)) {
+				if (g.Count() > 1) {
+					splitVariables.Add(g.Key);
+				}
+			}
 			foreach (var block in function.Descendants.OfType<Block>()) {
 				if (block.Kind != BlockKind.ControlFlow)
 					continue;
-				RunOnBlock(block, context);
+				RunOnBlock(block, context, splitVariables);
 			}
 		}
 
-		static void RunOnBlock(Block block, ILTransformContext context)
+		static void RunOnBlock(Block block, ILTransformContext context, HashSet<ILVariable> splitVariables = null)
 		{
 			for (int i = 0; i < block.Instructions.Count; i++) {
-				ILVariable v;
-				ILInstruction copiedExpr;
-				if (block.Instructions[i].MatchStLoc(out v, out copiedExpr)) {
+				if (block.Instructions[i].MatchStLoc(out ILVariable v, out ILInstruction copiedExpr)) {
 					if (v.IsSingleDefinition && v.LoadCount == 0 && v.Kind == VariableKind.StackSlot) {
 						// dead store to stack
 						if (SemanticHelper.IsPure(copiedExpr.Flags)) {
@@ -76,18 +76,21 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 							copiedExpr.AddILRange(block.Instructions[i]);
 							block.Instructions[i] = copiedExpr;
 						}
-					} else if (v.IsSingleDefinition && CanPerformCopyPropagation(v, copiedExpr)) {
+					} else if (v.IsSingleDefinition && CanPerformCopyPropagation(v, copiedExpr, splitVariables)) {
 						DoPropagate(v, copiedExpr, block, ref i, context);
 					}
 				}
 			}
 		}
 
-		static bool CanPerformCopyPropagation(ILVariable target, ILInstruction value)
+		static bool CanPerformCopyPropagation(ILVariable target, ILInstruction value, HashSet<ILVariable> splitVariables)
 		{
 			Debug.Assert(target.StackType == value.ResultType);
 			if (target.Type.IsSmallIntegerType())
 				return false;
+			if (splitVariables != null && splitVariables.Contains(target)) {
+				return false; // non-local code move might change semantics when there's split variables
+			}
 			switch (value.OpCode) {
 				case OpCode.LdLoca:
 //				case OpCode.LdElema:
@@ -100,6 +103,9 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 					return true;
 				case OpCode.LdLoc:
 					var v = ((LdLoc)value).Variable;
+					if (splitVariables != null && splitVariables.Contains(v)) {
+						return false; // non-local code move might change semantics when there's split variables
+					}
 					switch (v.Kind) {
 						case VariableKind.Parameter:
 							// Parameters can be copied only if they aren't assigned to (directly or indirectly via ldarga)

ICSharpCode.Decompiler/IL/Transforms/ILInlining.cs

@@ -249,7 +249,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			// Thus, we have to ensure we're operating on an r-value.
 			// Additionally, we cannot inline in cases where the C# compiler prohibits the direct use
 			// of the rvalue (e.g. M(ref (MyStruct)obj); is invalid).
-			if (!IsUsedAsThisPointerInCall(loadInst))
+			if (!IsUsedAsThisPointerInCall(loadInst, out var method))
 				return false;
 			switch (ClassifyExpression(inlinedExpression)) {
 				case ExpressionClassification.RValue:
@@ -261,14 +261,30 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				case ExpressionClassification.ReadonlyLValue:
 					// For struct method calls on readonly lvalues, the C# compiler
 					// only generates a temporary if it isn't a "readonly struct"
-					return !(v.Type.GetDefinition()?.IsReadOnly == true);
+					return MethodRequiresCopyForReadonlyLValue(method);
 				default:
 					throw new InvalidOperationException("invalid expression classification");
 			}
 		}
 
+		internal static bool MethodRequiresCopyForReadonlyLValue(IMethod method)
+		{
+			var type = method.DeclaringType;
+			if (type.IsReferenceType == true)
+				return false; // reference types are never implicitly copied
+			if (method.ThisIsRefReadOnly)
+				return false; // no copies for calls on readonly structs
+			return true;
+		}
+
 		internal static bool IsUsedAsThisPointerInCall(LdLoca ldloca)
 		{
+			return IsUsedAsThisPointerInCall(ldloca, out _);
+		}
+
+		static bool IsUsedAsThisPointerInCall(LdLoca ldloca, out IMethod method)
+		{
+			method = null;
 			if (ldloca.ChildIndex != 0)
 				return false;
 			if (ldloca.Variable.Type.IsReferenceType ?? false)
@@ -280,7 +296,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			switch (inst.Parent.OpCode) {
 				case OpCode.Call:
 				case OpCode.CallVirt:
-					var method = ((CallInstruction)inst.Parent).Method;
+					method = ((CallInstruction)inst.Parent).Method;
 					if (method.IsAccessor && method.AccessorKind != MethodSemanticsAttributes.Getter) {
 						// C# doesn't allow calling setters on temporary structs
 						return false;
@@ -313,7 +329,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			switch (inst.OpCode) {
 				case OpCode.LdLoc:
 				case OpCode.StLoc:
-					if (IsReadonlyRefLocal(((IInstructionWithVariableOperand)inst).Variable)) {
+					if (((IInstructionWithVariableOperand)inst).Variable.IsRefReadOnly) {
 						return ExpressionClassification.ReadonlyLValue;
 					} else {
 						return ExpressionClassification.MutableLValue;
@@ -347,7 +363,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			}
 		}
 
-		private static bool IsReadonlyReference(ILInstruction addr)
+		internal static bool IsReadonlyReference(ILInstruction addr)
 		{
 			switch (addr) {
 				case LdFlda ldflda:
@@ -356,7 +372,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				case LdsFlda ldsflda:
 					return ldsflda.Field.IsReadOnly;
 				case LdLoc ldloc:
-					return IsReadonlyRefLocal(ldloc.Variable);
+					return ldloc.Variable.IsRefReadOnly;
 				case Call call:
 					return call.Method.ReturnTypeIsRefReadOnly;
 				case AddressOf _:
@@ -367,19 +383,6 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			}
 		}
 
-		private static bool IsReadonlyRefLocal(ILVariable variable)
-		{
-			if (variable.Kind == VariableKind.Parameter) {
-				if (variable.Index == -1) {
-					// this parameter in readonly struct
-					return variable.Function.Method?.DeclaringTypeDefinition?.IsReadOnly == true;
-				} else {
-					return variable.Function.Parameters[variable.Index.Value].IsIn;
-				}
-			}
-			return false;
-		}
-
 		/// <summary>
 		/// Determines whether a variable should be inlined in non-aggressive mode, even though it is not a generated variable.
 		/// </summary>

ICSharpCode.Decompiler/IL/Transforms/IntroduceRefReadOnlyModifierOnLocals.cs

@@ -0,0 +1,57 @@
+// Copyright (c) 2018 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using ICSharpCode.Decompiler.IL.Transforms;
+using ICSharpCode.Decompiler.TypeSystem;
+
+namespace ICSharpCode.Decompiler.IL
+{
+	class IntroduceRefReadOnlyModifierOnLocals : IILTransform
+	{
+		public void Run(ILFunction function, ILTransformContext context)
+		{
+			foreach (var variable in function.Variables) {
+				if (variable.Type.Kind != TypeKind.ByReference || variable.Kind == VariableKind.Parameter)
+					continue;
+				// ref readonly
+				if (IsUsedAsRefReadonly(variable)) {
+					variable.IsRefReadOnly = true;
+					continue;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Infer ref readonly type from usage:
+		/// An ILVariable should be marked as readonly,
+		/// if it's a "by-ref-like" type and the initialized value is known to be readonly.
+		/// </summary>
+		bool IsUsedAsRefReadonly(ILVariable variable)
+		{
+			foreach (var store in variable.StoreInstructions.OfType<StLoc>()) {
+				if (ILInlining.IsReadonlyReference(store.Value))
+					return true;
+			}
+			return false;
+		}
+	}
+}

ICSharpCode.Decompiler/IL/Transforms/TransformDisplayClassUsage.cs

@@ -37,26 +37,19 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			public ILInstruction Initializer;
 			public ILVariable Variable;
 			public ITypeDefinition Definition;
-			public Dictionary<IField, DisplayClassVariable> Variables;
+			public Dictionary<IField, ILVariable> Variables;
 			public BlockContainer CaptureScope;
 			public ILFunction DeclaringFunction;
 		}
 
-		struct DisplayClassVariable
-		{
-			public ILVariable Variable;
-			public ILInstruction Value;
-		}
-
 		ILTransformContext context;
-		ILFunction currentFunction;
 		readonly Dictionary<ILVariable, DisplayClass> displayClasses = new Dictionary<ILVariable, DisplayClass>();
 		readonly List<ILInstruction> instructionsToRemove = new List<ILInstruction>();
 
 		public void Run(ILFunction function, ILTransformContext context)
 		{
 			try {
-				if (this.context != null || this.currentFunction != null)
+				if (this.context != null)
 					throw new InvalidOperationException("Reentrancy in " + nameof(TransformDisplayClassUsage));
 				this.context = context;
 				var decompilationContext = new SimpleTypeResolveContext(context.Function.Method);
@@ -73,12 +66,8 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 							AddOrUpdateDisplayClass(f, v, ((ByReferenceType)p.Type).ElementType.GetDefinition(), f.Body, localFunctionClosureParameter: true);
 						}
 					}
-					foreach (var displayClass in displayClasses.Values.OrderByDescending(d => d.Initializer.StartILOffset).ToArray()) {
-						context.Step($"Transform references to " + displayClass.Variable, displayClass.Initializer);
-						this.currentFunction = f;
-						VisitILFunction(f);
-					}
 				}
+				VisitILFunction(function);
 				if (instructionsToRemove.Count > 0) {
 					context.Step($"Remove instructions", function);
 					foreach (var store in instructionsToRemove) {
@@ -91,7 +80,6 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				instructionsToRemove.Clear();
 				displayClasses.Clear();
 				this.context = null;
-				this.currentFunction = null;
 			}
 		}
 
@@ -106,7 +94,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 					Initializer = inst,
 					Variable = v,
 					Definition = closureType,
-					Variables = new Dictionary<IField, DisplayClassVariable>(),
+					Variables = new Dictionary<IField, ILVariable>(),
 					CaptureScope = (isMono && IsMonoNestedCaptureScope(closureType)) || localFunctionClosureParameter ? null : v.CaptureScope,
 					DeclaringFunction = localFunctionClosureParameter ? f.DeclarationScope.Ancestors.OfType<ILFunction>().First() : f
 				});
@@ -151,11 +139,6 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			return false;
 		}
 
-		bool IsOuterClosureReference(IField field)
-		{
-			return displayClasses.Values.Any(disp => disp.Definition == field.DeclaringTypeDefinition);
-		}
-
 		bool IsMonoNestedCaptureScope(ITypeDefinition closureType)
 		{
 			var decompilationContext = new SimpleTypeResolveContext(context.Function.Method);
@@ -181,17 +164,14 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				Initializer = nestedFunction.Body,
 				Variable = thisVariable,
 				Definition = thisVariable.Type.GetDefinition(),
-				Variables = new Dictionary<IField, DisplayClassVariable>(),
+				Variables = new Dictionary<IField, ILVariable>(),
 				CaptureScope = (BlockContainer)nestedFunction.Body
 			};
 			displayClasses.Add(thisVariable, displayClass);
 			foreach (var stateMachineVariable in nestedFunction.Variables) {
 				if (stateMachineVariable.StateMachineField == null || displayClass.Variables.ContainsKey(stateMachineVariable.StateMachineField))
 					continue;
-				displayClass.Variables.Add(stateMachineVariable.StateMachineField, new DisplayClassVariable {
-					Variable = stateMachineVariable,
-					Value = new LdLoc(stateMachineVariable)
-				});
+				displayClass.Variables.Add(stateMachineVariable.StateMachineField, stateMachineVariable);
 			}
 			if (!currentFunction.Method.IsStatic && FindThisField(out var thisField)) {
 				var thisVar = currentFunction.Variables
@@ -200,7 +180,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 					thisVar = new ILVariable(VariableKind.Parameter, decompilationContext.CurrentTypeDefinition, -1) { Name = "this" };
 					currentFunction.Variables.Add(thisVar);
 				}
-				displayClass.Variables.Add(thisField, new DisplayClassVariable { Variable = thisVar, Value = new LdLoc(thisVar) });
+				displayClass.Variables.Add(thisField, thisVar);
 			}
 			return true;
 
@@ -263,11 +243,17 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			return true;
 		}
 
-		bool IsDisplayClassLoad(ILInstruction target, out ILVariable variable)
+		ILFunction currentFunction;
+
+		protected internal override void VisitILFunction(ILFunction function)
 		{
-			if (target.MatchLdLoc(out variable) || target.MatchLdLoca(out variable))
-				return true;
-			return false;
+			var oldFunction = this.currentFunction;
+			try {
+				this.currentFunction = function;
+				base.VisitILFunction(function);
+			} finally {
+				this.currentFunction = oldFunction;
+			}
 		}
 
 		protected override void Default(ILInstruction inst)
@@ -280,105 +266,102 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 		protected internal override void VisitStLoc(StLoc inst)
 		{
 			base.VisitStLoc(inst);
-			// Sometimes display class references are copied into other local variables.
-			// We remove the assignment and store the relationship between the display class and the variable in the
-			// displayClasses dictionary.
-			if (inst.Value.MatchLdLoc(out var closureVariable) && displayClasses.TryGetValue(closureVariable, out var displayClass)) {
-				displayClasses[inst.Variable] = displayClass;
-				instructionsToRemove.Add(inst);
-			} else if (inst.Variable.Kind == VariableKind.Local && inst.Variable.IsSingleDefinition && inst.Variable.LoadCount == 0 && inst.Value is StLoc) {
+
+			if (inst.Variable.Kind == VariableKind.Local && inst.Variable.IsSingleDefinition && inst.Variable.LoadCount == 0 && inst.Value is StLoc) {
+				context.Step($"Remove unused variable assignment {inst.Variable.Name}", inst);
 				inst.ReplaceWith(inst.Value);
 			}
 		}
 
 		protected internal override void VisitStObj(StObj inst)
 		{
-			base.VisitStObj(inst);
-			// This instruction has been marked deletable, do not transform it further
-			if (instructionsToRemove.Contains(inst))
-				return;
-			// The target of the store instruction must be a field reference
-			if (!inst.Target.MatchLdFlda(out ILInstruction target, out IField field))
-				return;
-			// Get display class info
-			if (!IsDisplayClassLoad(target, out var displayClassLoad) || !displayClasses.TryGetValue(displayClassLoad, out var displayClass))
-				return;
-			field = (IField)field.MemberDefinition;
-			if (displayClass.Variables.TryGetValue(field, out DisplayClassVariable info)) {
-				// If the display class field was previously initialized, we use a simple assignment.
-				inst.ReplaceWith(new StLoc(info.Variable, inst.Value).WithILRange(inst));
-			} else {
-				// This is an uninitialized variable:
-				ILInstruction value;
-				if (inst.Value.MatchLdLoc(out var v) && v.Kind == VariableKind.Parameter && currentFunction == v.Function) {
-					// Special case for parameters: remove copies of parameter values.
+			inst.Value.AcceptVisitor(this);
+			if (IsParameterAssignment(inst, out var displayClass, out var field, out var parameter)) {
+				context.Step($"Detected parameter assignment {parameter.Name}", inst);
+				displayClass.Variables.Add(field, parameter);
+				instructionsToRemove.Add(inst);
+			} else if (IsDisplayClassAssignment(inst, out displayClass, out field, out var variable)) {
+				context.Step($"Detected display-class assignment {variable.Name}", inst);
+				displayClass.Variables.Add(field, variable);
 				instructionsToRemove.Add(inst);
-					value = inst.Value;
 			} else {
-					context.Step($"Introduce captured variable for {field.FullName}", inst);
-					Debug.Assert(displayClass.Definition == field.DeclaringTypeDefinition);
-					// Introduce a fresh variable for the display class field.
-					if (displayClass.IsMono && displayClass.CaptureScope == null && !IsOuterClosureReference(field)) {
-						displayClass.CaptureScope = BlockContainer.FindClosestContainer(inst);
-					}
-					v = displayClass.DeclaringFunction.RegisterVariable(VariableKind.Local, field.Type, field.Name);
-					v.HasInitialValue = true;
-					v.CaptureScope = displayClass.CaptureScope;
-					inst.ReplaceWith(new StLoc(v, inst.Value).WithILRange(inst));
-					value = new LdLoc(v);
-				}
-				displayClass.Variables.Add(field, new DisplayClassVariable { Value = value, Variable = v });
+				inst.Target.AcceptVisitor(this);
+				EarlyExpressionTransforms.StObjToStLoc(inst, context);
 			}
 		}
 
 		protected internal override void VisitLdObj(LdObj inst)
 		{
 			base.VisitLdObj(inst);
-			// The target of the store instruction must be a field reference
-			if (!inst.Target.MatchLdFlda(out var target, out IField field))
-				return;
-			// Get display class info
-			if (!IsDisplayClassLoad(target, out var displayClassLoad) || !displayClasses.TryGetValue(displayClassLoad, out var displayClass))
-				return;
-			// Get display class variable info
-			if (!displayClass.Variables.TryGetValue((IField)field.MemberDefinition, out DisplayClassVariable info))
-				return;
-			// Replace usage of display class field with the variable.
-			var replacement = info.Value.Clone();
-			replacement.SetILRange(inst);
-			inst.ReplaceWith(replacement);
+			EarlyExpressionTransforms.LdObjToLdLoc(inst, context);
+		}
+
+		private bool IsDisplayClassLoad(ILInstruction target, out ILVariable variable)
+		{
+			// We cannot use MatchLdLocRef here because local functions use ref parameters
+			if (target.MatchLdLoc(out variable) || target.MatchLdLoca(out variable))
+				return true;
+			return false;
+		}
+
+		private bool IsDisplayClassAssignment(StObj inst, out DisplayClass displayClass, out IField field, out ILVariable variable)
+		{
+			variable = null;
+			if (!IsDisplayClassFieldAccess(inst.Target, out var displayClassVar, out displayClass, out field))
+				return false;
+			if (!(inst.Value.MatchLdLoc(out var v) && displayClasses.ContainsKey(v)))
+				return false;
+			if (displayClassVar.Function != currentFunction)
+				return false;
+			variable = v;
+			return true;
+		}
+
+		private bool IsParameterAssignment(StObj inst, out DisplayClass displayClass, out IField field, out ILVariable parameter)
+		{
+			parameter = null;
+			if (!IsDisplayClassFieldAccess(inst.Target, out var displayClassVar, out displayClass, out field))
+				return false;
+			if (!(inst.Value.MatchLdLoc(out var v) && v.Kind == VariableKind.Parameter && v.Function == currentFunction))
+				return false;
+			if (displayClass.Variables.ContainsKey(field))
+				return false;
+			if (displayClassVar.Function != currentFunction)
+				return false;
+			parameter = v;
+			return true;
+		}
+
+		private bool IsDisplayClassFieldAccess(ILInstruction inst, out ILVariable displayClassVar, out DisplayClass displayClass, out IField field)
+		{
+			displayClass = null;
+			displayClassVar = null;
+			field = null;
+			if (!(inst is LdFlda ldflda))
+				return false;
+			field = (IField)ldflda.Field.MemberDefinition;
+			return IsDisplayClassLoad(ldflda.Target, out displayClassVar)
+				&& displayClasses.TryGetValue(displayClassVar, out displayClass);
 		}
 
 		protected internal override void VisitLdFlda(LdFlda inst)
 		{
 			base.VisitLdFlda(inst);
-			// TODO : Figure out why this was added in https://github.com/icsharpcode/ILSpy/pull/1303
-			if (inst.Target.MatchLdThis() && inst.Field.Name == "$this"
-				&& inst.Field.MemberDefinition.ReflectionName.Contains("c__Iterator")) {
-				//Debug.Assert(false, "This should not be executed!");
-				var variable = currentFunction.Variables.First((f) => f.Index == -1);
-				inst.ReplaceWith(new LdLoca(variable).WithILRange(inst));
-			}
-			// Skip stfld/ldfld
-			if (inst.Parent is LdObj || inst.Parent is StObj)
-				return;
 			// Get display class info
-			if (!IsDisplayClassLoad(inst.Target, out var displayClassLoad) || !displayClasses.TryGetValue(displayClassLoad, out var displayClass))
+			if (!IsDisplayClassFieldAccess(inst, out _, out DisplayClass displayClass, out IField field))
 				return;
-			var field = (IField)inst.Field.MemberDefinition;
-			if (!displayClass.Variables.TryGetValue(field, out DisplayClassVariable info)) {
+			if (!displayClass.Variables.TryGetValue(field, out var v)) {
 				context.Step($"Introduce captured variable for {field.FullName}", inst);
 				// Introduce a fresh variable for the display class field.
 				Debug.Assert(displayClass.Definition == field.DeclaringTypeDefinition);
-				var v = displayClass.DeclaringFunction.RegisterVariable(VariableKind.Local, field.Type, field.Name);
+				v = displayClass.DeclaringFunction.RegisterVariable(VariableKind.Local, field.Type, field.Name);
 				v.HasInitialValue = true;
 				v.CaptureScope = displayClass.CaptureScope;
 				inst.ReplaceWith(new LdLoca(v).WithILRange(inst));
-				displayClass.Variables.Add(field, new DisplayClassVariable { Value = new LdLoc(v), Variable = v });
-			} else if (info.Value is LdLoc l) {
-				inst.ReplaceWith(new LdLoca(l.Variable).WithILRange(inst));
+				displayClass.Variables.Add(field, v);
 			} else {
-				Debug.Fail("LdFlda pattern not supported!");
+				context.Step($"Reuse captured variable {v.Name} for {field.FullName}", inst);
+				inst.ReplaceWith(new LdLoca(v).WithILRange(inst));
 			}
 		}
 	}

ICSharpCode.Decompiler/Metadata/DotNetCorePathFinder.cs

@@ -53,6 +53,13 @@ namespace ICSharpCode.Decompiler.Metadata
 			 Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".nuget", "packages")
 		};
 
+		static readonly string[] RuntimePacks = new[] {
+			"Microsoft.NETCore.App",
+			"Microsoft.WindowsDesktop.App",
+			"Microsoft.AspNetCore.App",
+			"Microsoft.AspNetCore.All"
+		};
+
 		readonly Dictionary<string, DotNetCorePackageInfo> packages;
 		ISet<string> packageBasePaths = new HashSet<string>(StringComparer.Ordinal);
 		readonly string assemblyName;
@@ -124,14 +131,17 @@ namespace ICSharpCode.Decompiler.Metadata
 
 		string FallbackToDotNetSharedDirectory(IAssemblyReference name, Version version)
 		{
-			if (dotnetBasePath == null) return null;
-			var basePath = Path.Combine(dotnetBasePath, "shared", "Microsoft.NETCore.App");
+			if (dotnetBasePath == null)
+				return null;
+			var basePaths = RuntimePacks.Select(pack => Path.Combine(dotnetBasePath, "shared", pack));
+			foreach (var basePath in basePaths) {
 				var closestVersion = GetClosestVersionFolder(basePath, version);
 				if (File.Exists(Path.Combine(basePath, closestVersion, name.Name + ".dll"))) {
 					return Path.Combine(basePath, closestVersion, name.Name + ".dll");
 				} else if (File.Exists(Path.Combine(basePath, closestVersion, name.Name + ".exe"))) {
 					return Path.Combine(basePath, closestVersion, name.Name + ".exe");
 				}
+			}
 			return null;
 		}
 

ICSharpCode.Decompiler/Metadata/MetadataExtensions.cs

@@ -49,7 +49,7 @@ namespace ICSharpCode.Decompiler.Metadata
 			return publicKeyTokenBytes.TakeLast(8).Reverse().ToHexString(8);
 		}
 
-		public static string GetFullAssemblyName(this MetadataReader reader)
+		public static string GetPublicKeyToken(this MetadataReader reader)
 		{
 			if (!reader.IsAssembly)
 				return string.Empty;
@@ -59,6 +59,15 @@ namespace ICSharpCode.Decompiler.Metadata
 				// AssemblyFlags.PublicKey does not apply to assembly definitions
 				publicKey = CalculatePublicKeyToken(asm.PublicKey, reader);
 			}
+			return publicKey;
+		}
+
+		public static string GetFullAssemblyName(this MetadataReader reader)
+		{
+			if (!reader.IsAssembly)
+				return string.Empty;
+			var asm = reader.GetAssemblyDefinition();
+			string publicKey = reader.GetPublicKeyToken();
 			return $"{reader.GetString(asm.Name)}, " +
 				$"Version={asm.Version}, " +
 				$"Culture={(asm.Culture.IsNil ? "neutral" : reader.GetString(asm.Culture))}, " +

ICSharpCode.Decompiler/TypeSystem/DecompilerTypeSystem.cs

@@ -84,7 +84,8 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		/// </summary>
 		KeepModifiers = 0x40,
 		/// <summary>
-		/// If this option is active, [IsReadOnlyAttribute] is removed and parameters are marked as in, structs as readonly.
+		/// If this option is active, [IsReadOnlyAttribute] on parameters+structs is removed
+		/// and parameters are marked as in, structs as readonly.
 		/// Otherwise, the attribute is preserved but the parameters and structs are not marked.
 		/// </summary>
 		ReadOnlyStructsAndParameters = 0x80,
@@ -104,10 +105,15 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		/// </summary>
 		NullabilityAnnotations = 0x400,
 		/// <summary>
+		/// If this option is active, [IsReadOnlyAttribute] on methods is removed
+		/// and the method marked as ThisIsRefReadOnly.
+		/// </summary>
+		ReadOnlyMethods = 0x800,
+		/// <summary>
 		/// Default settings: typical options for the decompiler, with all C# languages features enabled.
 		/// </summary>
 		Default = Dynamic | Tuple | ExtensionMethods | DecimalConstants | ReadOnlyStructsAndParameters
-			| RefStructs | UnmanagedConstraints | NullabilityAnnotations
+			| RefStructs | UnmanagedConstraints | NullabilityAnnotations | ReadOnlyMethods
 	}
 
 	/// <summary>
@@ -137,6 +143,8 @@ namespace ICSharpCode.Decompiler.TypeSystem
 				typeSystemOptions |= TypeSystemOptions.UnmanagedConstraints;
 			if (settings.NullableReferenceTypes)
 				typeSystemOptions |= TypeSystemOptions.NullabilityAnnotations;
+			if (settings.ReadOnlyMethods)
+				typeSystemOptions |= TypeSystemOptions.ReadOnlyMethods;
 			return typeSystemOptions;
 		}
 

ICSharpCode.Decompiler/TypeSystem/IMethod.cs

@@ -40,6 +40,12 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		/// </summary>
 		bool ReturnTypeIsRefReadOnly { get; }
 
+		/// <summary>
+		/// Gets whether the method accepts the 'this' reference as ref readonly.
+		/// This can be either because the method is C# 8.0 'readonly', or because it is within a C# 7.2 'readonly struct'
+		/// </summary>
+		bool ThisIsRefReadOnly { get; }
+
 		/// <summary>
 		/// Gets the type parameters of this method; or an empty list if the method is not generic.
 		/// </summary>

ICSharpCode.Decompiler/TypeSystem/Implementation/AttributeListBuilder.cs

@@ -201,7 +201,16 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 						case "DecimalConstantAttribute":
 							return (options & TypeSystemOptions.DecimalConstants) != 0 && (target == SymbolKind.Field || target == SymbolKind.Parameter);
 						case "IsReadOnlyAttribute":
+							switch (target) {
+								case SymbolKind.TypeDefinition:
+								case SymbolKind.Parameter:
 									return (options & TypeSystemOptions.ReadOnlyStructsAndParameters) != 0;
+								case SymbolKind.Method:
+								case SymbolKind.Accessor:
+									return (options & TypeSystemOptions.ReadOnlyMethods) != 0;
+								default:
+									return false;
+							}
 						case "IsByRefLikeAttribute":
 							return (options & TypeSystemOptions.RefStructs) != 0 && target == SymbolKind.TypeDefinition;
 						case "IsUnmanagedAttribute":

ICSharpCode.Decompiler/TypeSystem/Implementation/FakeMember.cs

@@ -133,6 +133,7 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		
 		IEnumerable<IAttribute> IMethod.GetReturnTypeAttributes() => EmptyList<IAttribute>.Instance;
 		bool IMethod.ReturnTypeIsRefReadOnly => false;
+		bool IMethod.ThisIsRefReadOnly => false;
 
 		public IReadOnlyList<ITypeParameter> TypeParameters { get; set; } = EmptyList<ITypeParameter>.Instance;
 

ICSharpCode.Decompiler/TypeSystem/Implementation/LocalFunctionMethod.cs

@@ -117,6 +117,7 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		IEnumerable<IAttribute> IEntity.GetAttributes() => baseMethod.GetAttributes();
 		IEnumerable<IAttribute> IMethod.GetReturnTypeAttributes() => baseMethod.GetReturnTypeAttributes();
 		bool IMethod.ReturnTypeIsRefReadOnly => baseMethod.ReturnTypeIsRefReadOnly;
+		bool IMethod.ThisIsRefReadOnly => baseMethod.ThisIsRefReadOnly;
 		/// <summary>
 		/// We consider local functions as always static, because they do not have a "this parameter".
 		/// Even local functions in instance methods capture this.

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataMethod.cs

@@ -49,6 +49,7 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		IParameter[] parameters;
 		IType returnType;
 		byte returnTypeIsRefReadonly = ThreeState.Unknown;
+		byte thisIsRefReadonly = ThreeState.Unknown;
 
 		internal MetadataMethod(MetadataModule module, MethodDefinitionHandle handle)
 		{
@@ -424,6 +425,23 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 				return hasReadOnlyAttr;
 			}
 		}
+
+		public bool ThisIsRefReadOnly {
+			get {
+				if (thisIsRefReadonly != ThreeState.Unknown) {
+					return thisIsRefReadonly == ThreeState.True;
+				}
+				var metadata = module.metadata;
+				var methodDefinition = metadata.GetMethodDefinition(handle);
+				bool hasReadOnlyAttr = DeclaringTypeDefinition?.IsReadOnly ?? false;
+				if ((module.TypeSystemOptions & TypeSystemOptions.ReadOnlyMethods) != 0) {
+					hasReadOnlyAttr |= methodDefinition.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.IsReadOnly);
+				}
+				this.thisIsRefReadonly = ThreeState.From(hasReadOnlyAttr);
+				return hasReadOnlyAttr;
+			}
+		}
+
 		#endregion
 
 		public Accessibility Accessibility => GetAccessibility(attributes);

ICSharpCode.Decompiler/TypeSystem/Implementation/SpecializedMethod.cs

@@ -97,6 +97,8 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		public IEnumerable<IAttribute> GetReturnTypeAttributes() => methodDefinition.GetReturnTypeAttributes();
 		public bool ReturnTypeIsRefReadOnly => methodDefinition.ReturnTypeIsRefReadOnly;
 
+		bool IMethod.ThisIsRefReadOnly => methodDefinition.ThisIsRefReadOnly;
+
 		public IReadOnlyList<ITypeParameter> TypeParameters {
 			get {
 				return specializedTypeParameters ?? methodDefinition.TypeParameters;

ICSharpCode.Decompiler/TypeSystem/VarArgInstanceMethod.cs

@@ -114,6 +114,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		IEnumerable<IAttribute> IEntity.GetAttributes() => baseMethod.GetAttributes();
 		IEnumerable<IAttribute> IMethod.GetReturnTypeAttributes() => baseMethod.GetReturnTypeAttributes();
 		bool IMethod.ReturnTypeIsRefReadOnly => baseMethod.ReturnTypeIsRefReadOnly;
+		bool IMethod.ThisIsRefReadOnly => baseMethod.ThisIsRefReadOnly;
 
 		public IReadOnlyList<ITypeParameter> TypeParameters {
 			get { return baseMethod.TypeParameters; }

ILSpy.AddIn/AssemblyFileFinder.cs

@@ -15,35 +15,13 @@ namespace ICSharpCode.ILSpy.AddIn
 	{
 		public static string FindAssemblyFile(AssemblyDefinition assemblyDefinition, string assemblyFile)
 		{
-			var assemblyName = assemblyDefinition.Name;
-
-			var detectedTargetFramework = DetectTargetFrameworkId(assemblyDefinition, assemblyFile);
-			if (string.IsNullOrEmpty(detectedTargetFramework)) {
-				// Without a target framework id it makes no sense to continue
-				return null;
-			}
-
-			var targetFramework = detectedTargetFramework.Split(new[] { ",Version=v" }, StringSplitOptions.None);
-			string file = null;
-			switch (targetFramework[0]) {
-				case ".NETCoreApp":
-				case ".NETStandard":
-					if (targetFramework.Length != 2)
-						return FindAssemblyFromGAC(assemblyDefinition);
-					var version = targetFramework[1].Length == 3 ? new Version(targetFramework[1] + ".0") : new Version(targetFramework[1]);
-					var dotNetCorePathFinder = new DotNetCorePathFinder(assemblyFile, detectedTargetFramework, version);
-					file = dotNetCorePathFinder.TryResolveDotNetCore(Decompiler.Metadata.AssemblyNameReference.Parse(assemblyName.FullName));
-					if (file != null)
-						return file;
-					return FindAssemblyFromGAC(assemblyDefinition);
-				default:
-					return FindAssemblyFromGAC(assemblyDefinition);
+			var assemblyResolver = new UniversalAssemblyResolver(assemblyFile, false,
+				DetectTargetFrameworkId(assemblyDefinition, assemblyFile));
+			if (IsReferenceAssembly(assemblyDefinition, assemblyFile)) {
+				assemblyResolver.RemoveSearchDirectory(Path.GetDirectoryName(assemblyFile));
 			}
-		}
-
-		static string FindAssemblyFromGAC(AssemblyDefinition assemblyDefinition)
-		{
-			return GacInterop.FindAssemblyInNetGac(Decompiler.Metadata.AssemblyNameReference.Parse(assemblyDefinition.Name.FullName));
+			return assemblyResolver.FindAssemblyFile(
+				ICSharpCode.Decompiler.Metadata.AssemblyNameReference.Parse(assemblyDefinition.Name.FullName));
 		}
 
 		static readonly string RefPathPattern = @"NuGetFallbackFolder[/\\][^/\\]+[/\\][^/\\]+[/\\]ref[/\\]";
@@ -60,7 +38,7 @@ namespace ICSharpCode.ILSpy.AddIn
 
 		static readonly string DetectTargetFrameworkIdRefPathPattern =
 			@"(Reference Assemblies[/\\]Microsoft[/\\]Framework[/\\](?<1>.NETFramework)[/\\]v(?<2>[^/\\]+)[/\\])" +
-			@"|(NuGetFallbackFolder[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\]ref[/\\])";
+			@"|((NuGetFallbackFolder|packs)[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\]ref[/\\])";
 
 		public static string DetectTargetFrameworkId(AssemblyDefinition assembly, string assemblyPath = null)
 		{
@@ -85,6 +63,7 @@ namespace ICSharpCode.ILSpy.AddIn
 				 * 
 				 * - .NETFramework -> C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\mscorlib.dll
 				 * - .NETCore      -> C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.netcore.app\2.1.0\ref\netcoreapp2.1\System.Console.dll
+				 *                 -> C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\3.0.0\ref\netcoreapp3.0\System.Runtime.Extensions.dll
 				 * - .NETStandard  -> C:\Program Files\dotnet\sdk\NuGetFallbackFolder\netstandard.library\2.0.3\build\netstandard2.0\ref\netstandard.dll
 				 */
 				var pathMatch = Regex.Match(assemblyPath, DetectTargetFrameworkIdRefPathPattern,
@@ -95,9 +74,9 @@ namespace ICSharpCode.ILSpy.AddIn
 
 					if (type == ".NETFramework") {
 						return $".NETFramework,Version=v{version}";
-					} else if (type.Contains("netcore")) {
+					} else if (type.ToLower().Contains("netcore")) {
 						return $".NETCoreApp,Version=v{version}";
-					} else if (type.Contains("netstandard")) {
+					} else if (type.ToLower().Contains("netstandard")) {
 						return $".NETStandard,Version=v{version}";
 					}
 				}

ILSpy.AddIn/Commands/NuGetReferenceForILSpy.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using EnvDTE;
+using Microsoft.VisualStudio.Shell;
 
 namespace ICSharpCode.ILSpy.AddIn.Commands
 {
@@ -26,6 +27,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 		/// <returns><see cref="NuGetReferenceForILSpy"/> instance or <c>null</c>, if item is not a supported project.</returns>
 		public static NuGetReferenceForILSpy Detect(object itemData)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (itemData is ProjectItem projectItem) {
 				var properties = Utils.GetProperties(projectItem.Properties, "Type");
 				if ((properties[0] as string) == "Package") {
@@ -42,6 +45,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 		/// <returns>Parameters object or <c>null, if not applicable.</c></returns>
 		public ILSpyParameters GetILSpyParameters()
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var properties = Utils.GetProperties(projectItem.Properties, "Name", "Version", "Path");
 			if (properties[0] != null && properties[1] != null && properties[2] != null) {
 				return new ILSpyParameters(new[] { $"{properties[2]}\\{properties[0]}.{properties[1]}.nupkg" });

ILSpy.AddIn/Commands/OpenCodeItemCommand.cs

@@ -23,6 +23,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected override void OnBeforeQueryStatus(object sender, EventArgs e)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (sender is OleMenuCommand menuItem) {
 				menuItem.Visible = false;
 
@@ -46,6 +48,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		Document GetRoslynDocument()
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var document = owner.DTE.ActiveDocument;
 			var selection = (EnvDTE.TextPoint)((EnvDTE.TextSelection)document.Selection).ActivePoint;
 			var id = owner.Workspace.CurrentSolution.GetDocumentIdsWithFilePath(document.FullName).FirstOrDefault();
@@ -57,18 +61,26 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		EnvDTE.TextPoint GetEditorSelection()
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var document = owner.DTE.ActiveDocument;
 			return ((EnvDTE.TextSelection)document.Selection).ActivePoint;
 		}
 
 		protected override async void OnExecute(object sender, EventArgs e)
 		{
+			await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
+
 			var textView = Utils.GetCurrentViewHost(owner)?.TextView;
 			if (textView == null)
 				return;
 
 			SnapshotPoint caretPosition = textView.Caret.Position.BufferPosition;
 			var roslynDocument = GetRoslynDocument();
+			if (roslynDocument == null) {
+				owner.ShowMessage("This element is not analyzable in current view.");
+				return;
+			}
 			var ast = await roslynDocument.GetSyntaxRootAsync().ConfigureAwait(false);
 			var model = await roslynDocument.GetSemanticModelAsync().ConfigureAwait(false);
 			var node = ast.FindNode(new TextSpan(caretPosition.Position, 0), false, true);
@@ -89,6 +101,7 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 			// Add our own project as well (not among references)
 			var project = FindProject(owner.DTE.Solution.Projects.OfType<EnvDTE.Project>(), roslynProject.FilePath);
+
 			if (project == null) {
 				owner.ShowMessage(OLEMSGICON.OLEMSGICON_WARNING, "Can't show ILSpy for this code element!");
 				return;

ILSpy.AddIn/Commands/OpenILSpyCommand.cs

@@ -55,6 +55,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected void OpenAssembliesInILSpy(ILSpyParameters parameters)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (parameters == null)
 				return;
 
@@ -71,18 +73,15 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected Dictionary<string, DetectedReference> GetReferences(Microsoft.CodeAnalysis.Project parentProject)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var dict = new Dictionary<string, DetectedReference>();
 			foreach (var reference in parentProject.MetadataReferences) {
 				using (var assemblyDef = AssemblyDefinition.ReadAssembly(reference.Display)) {
 					string assemblyName = assemblyDef.Name.Name;
-					if (AssemblyFileFinder.IsReferenceAssembly(assemblyDef, reference.Display)) {
 					string resolvedAssemblyFile = AssemblyFileFinder.FindAssemblyFile(assemblyDef, reference.Display);
 					dict.Add(assemblyName,
 						new DetectedReference(assemblyName, resolvedAssemblyFile, false));
-					} else {
-						dict.Add(assemblyName, 
-							new DetectedReference(assemblyName, reference.Display, false));
-					}
 				}
 			}
 			foreach (var projectReference in parentProject.ProjectReferences) {
@@ -97,17 +96,28 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected EnvDTE.Project FindProject(IEnumerable<EnvDTE.Project> projects, string projectFile)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			foreach (var project in projects) {
-				if (project.Kind == DTEConstants.vsProjectKindSolutionItems) {
+				switch (project.Kind) {
+					case DTEConstants.vsProjectKindSolutionItems:
 						// This is a solution folder -> search in sub-projects
 						var subProject = FindProject(
 							project.ProjectItems.OfType<EnvDTE.ProjectItem>().Select(pi => pi.SubProject).OfType<EnvDTE.Project>(),
 							projectFile);
 						if (subProject != null)
 							return subProject;
-				} else {
+						break;
+
+					case DTEConstants.vsProjectKindUnmodeled:
+						// Skip unloaded projects completely
+						break;
+
+					default:
+						// Match by project's file name
 						if (project.FileName == projectFile)
 							return project;
+						break;
 				}
 			}
 

ILSpy.AddIn/Commands/OpenProjectOutputCommand.cs

@@ -17,6 +17,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected override void OnBeforeQueryStatus(object sender, EventArgs e)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (sender is OleMenuCommand menuItem) {
 				menuItem.Visible = false;
 
@@ -27,6 +29,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected override void OnExecute(object sender, EventArgs e)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (owner.DTE.SelectedItems.Count != 1)
 				return;
 			var projectItemWrapper = ProjectItemForILSpy.Detect(owner, owner.DTE.SelectedItems.Item(1));

ILSpy.AddIn/Commands/OpenReferenceCommand.cs

@@ -22,6 +22,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected override void OnBeforeQueryStatus(object sender, EventArgs e)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (sender is OleMenuCommand menuItem) {
 				menuItem.Visible = false;
 
@@ -44,6 +46,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 
 		protected override void OnExecute(object sender, EventArgs e)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var itemObject = owner.GetSelectedItemsData<object>().FirstOrDefault();
 			if (itemObject == null)
 				return;

ILSpy.AddIn/Commands/ProjectItemForILSpy.cs

@@ -1,6 +1,7 @@
 using System.IO;
 using System.Linq;
 using EnvDTE;
+using Microsoft.VisualStudio.Shell;
 
 namespace ICSharpCode.ILSpy.AddIn.Commands
 {
@@ -27,6 +28,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 		/// <returns><see cref="ProjectItemForILSpy"/> instance or <c>null</c>, if item is not a supported project.</returns>
 		public static ProjectItemForILSpy Detect(ILSpyAddInPackage package, SelectedItem item)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var project = item.Project;
 			var roslynProject = package.Workspace.CurrentSolution.Projects.FirstOrDefault(p => p.FilePath == project.FileName);
 			if (roslynProject == null)
@@ -42,6 +45,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 		/// <returns>Parameters object or <c>null, if not applicable.</c></returns>
 		public ILSpyParameters GetILSpyParameters(ILSpyAddInPackage package)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			return new ILSpyParameters(new[] { Utils.GetProjectOutputAssembly(project, roslynProject) });
 		}
 	}

ILSpy.AddIn/Commands/ProjectReferenceForILSpy.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using EnvDTE;
+using Microsoft.VisualStudio.Shell;
 using Mono.Cecil;
 
 namespace ICSharpCode.ILSpy.AddIn.Commands
@@ -31,6 +32,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 		/// <returns><see cref="ProjectReferenceForILSpy"/> instance or <c>null</c>, if item is not a supported project.</returns>
 		public static ProjectReferenceForILSpy Detect(object itemData)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (itemData is ProjectItem projectItem) {
 				var properties = Utils.GetProperties(projectItem.Properties, "FusionName", "ResolvedPath");
 				string fusionName = properties[0] as string;
@@ -50,6 +53,8 @@ namespace ICSharpCode.ILSpy.AddIn.Commands
 		/// <returns>Parameters object or <c>null, if not applicable.</c></returns>
 		public ILSpyParameters GetILSpyParameters(Dictionary<string, DetectedReference> projectReferences)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			string fileName = projectItem.ContainingProject?.FileName;
 			if (!string.IsNullOrEmpty(fileName)) {
 				if (projectReferences.TryGetValue(projectItem.Name, out DetectedReference path)) {

ILSpy.AddIn/ILSpy.AddIn.csproj

@@ -44,27 +44,15 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="EnvDTE" Version="8.0.2" />
-    <PackageReference Include="EnvDTE80" Version="8.0.2" />
+    <PackageReference Include="Microsoft.VisualStudio.SDK " Version="15.9.3" />
     <PackageReference Include="Microsoft.CodeAnalysis" Version="2.4.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="2.4.0" />
-    <PackageReference Include="Microsoft.VisualStudio.ComponentModelHost" Version="15.6.27413" />
-    <PackageReference Include="Microsoft.VisualStudio.Editor" Version="15.6.27740" />
     <PackageReference Include="Microsoft.VisualStudio.LanguageServices" Version="2.4.0" />
-    <PackageReference Include="Microsoft.VisualStudio.SDK.Analyzers" Version="16.0.29" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.15.0" Version="15.6.27413" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.14.0.DesignTime" Version="14.3.26929" />
-    <PackageReference Include="Microsoft.VisualStudio.Text.UI" Version="15.6.27740" />
-    <PackageReference Include="Microsoft.VisualStudio.Text.UI.Wpf" Version="15.6.27740" />
-    <PackageReference Include="Microsoft.VisualStudio.Threading" Version="15.6.56" />
     <PackageReference Include="Mono.Cecil" Version="0.10.3" />
-    <PackageReference Include="VSLangProj" Version="7.0.3301" />
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\ICSharpCode.Decompiler\ICSharpCode.Decompiler.csproj" />
     <ProjectReference Include="..\ILSpy\ILSpy.csproj" />
-    <ProjectReference Include="..\SharpTreeView\ICSharpCode.TreeView.csproj" />
   </ItemGroup>
 
   <ItemGroup>
@@ -131,6 +119,7 @@
     <AdditionalDependencies Include="$(ILSpyBuildPath)ILSpy.BamlDecompiler.Plugin.dll" />
 	  <AdditionalDependencies Include="$(ILSpyBuildPath)Microsoft.DiaSymReader*.dll" />
   	<AdditionalDependencies Include="$(ILSpyBuildPath)OSVersionHelper.dll" />
+    <AdditionalDependencies Include="$(ILSpyBuildPath)Xceed.Wpf.AvalonDock.dll" />
   </ItemGroup>
 
   <ItemGroup>

ILSpy.AddIn/ILSpyAddInPackage.cs

@@ -113,6 +113,10 @@ namespace ICSharpCode.ILSpy.AddIn
 			ThreadHelper.ThrowIfNotOnUIThread();
 
 			IVsUIShell uiShell = (IVsUIShell)GetService(typeof(SVsUIShell));
+			if (uiShell == null) {
+				return 0;
+			}
+
 			Guid clsid = Guid.Empty;
 			int result;
 			Microsoft.VisualStudio.ErrorHandler.ThrowOnFailure(
@@ -136,6 +140,8 @@ namespace ICSharpCode.ILSpy.AddIn
 
 		public IEnumerable<T> GetSelectedItemsData<T>()
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			if (DTE.ToolWindows.SolutionExplorer.SelectedItems is IEnumerable<UIHierarchyItem> hierarchyItems) {
 				foreach (var item in hierarchyItems) {
 					if (item.Object is T typedItem) {

ILSpy.AddIn/ILSpyInstance.cs

@@ -42,7 +42,8 @@ namespace ICSharpCode.ILSpy.AddIn
 			var process = new Process() {
 				StartInfo = new ProcessStartInfo() {
 					FileName = GetILSpyPath(),
-					UseShellExecute = false
+					UseShellExecute = false,
+					Arguments = "/navigateTo:none"
 				}
 			};
 			process.Start();
@@ -53,6 +54,7 @@ namespace ICSharpCode.ILSpy.AddIn
 			}
 		}
 
+		[System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "VSTHRD110:Observe result of async calls", Justification = "<Pending>")]
 		void SendMessage(Process ilspyProcess, string message, bool activate)
 		{
 			// We wait asynchronously until target window can be found and try to find it multiple times

ILSpy.AddIn/README.md

@@ -0,0 +1,3 @@
+Test cases for various types of projects as well as corresponding test plans are located in a separate repository.
+
+[https://github.com/icsharpcode/ILSpy-Addin-tests](https://github.com/icsharpcode/ILSpy-Addin-tests)

ILSpy.AddIn/Utils.cs

@@ -8,6 +8,7 @@ using System.Text;
 using EnvDTE;
 using Microsoft.VisualStudio.Editor;
 using Microsoft.VisualStudio.LanguageServices;
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Text;
 using Microsoft.VisualStudio.Text.Editor;
 using Microsoft.VisualStudio.TextManager.Interop;
@@ -148,6 +149,8 @@ namespace ICSharpCode.ILSpy.AddIn
 
 		public static object[] GetProperties(EnvDTE.Properties properties, params string[] names)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var values = new object[names.Length];
 			foreach (object p in properties) {
 				try {
@@ -168,6 +171,8 @@ namespace ICSharpCode.ILSpy.AddIn
 
 		public static List<(string, object)> GetAllProperties(EnvDTE.Properties properties)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			var result = new List<(string, object)>();
 			for (int i = 0; i < properties.Count; i++) {
 				try {
@@ -207,6 +212,10 @@ namespace ICSharpCode.ILSpy.AddIn
 		public static IWpfTextViewHost GetCurrentViewHost(IServiceProvider serviceProvider)
 		{
 			IVsTextManager txtMgr = (IVsTextManager)serviceProvider.GetService(typeof(SVsTextManager));
+			if (txtMgr == null) {
+				return null;
+			}
+
 			IVsTextView vTextView = null;
 			int mustHaveFocus = 1;
 			txtMgr.GetActiveView(mustHaveFocus, null, out vTextView);
@@ -235,6 +244,8 @@ namespace ICSharpCode.ILSpy.AddIn
 
 		public static string GetProjectOutputAssembly(Project project, Microsoft.CodeAnalysis.Project roslynProject)
 		{
+			ThreadHelper.ThrowIfNotOnUIThread();
+
 			string outputFileName = Path.GetFileName(roslynProject.OutputFilePath);
 
 			// Get the directory path based on the project file.

ILSpy.BamlDecompiler/ILSpy.BamlDecompiler.csproj

@@ -32,12 +32,12 @@
   <ItemGroup>
     <Reference Include="PresentationCore" />
     <Reference Include="PresentationFramework" />
-    <Reference Include="System.ComponentModel.Composition" />
     <Reference Include="WindowsBase" />
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="AvalonEdit" Version="6.0.0-rc1" />
+    <PackageReference Include="AvalonEdit" Version="6.0.0" />
+    <PackageReference Include="System.Composition" Version="1.3.0" />
   </ItemGroup>
 
   <ItemGroup>

ILSpy.Tests/ILSpy.Tests.csproj

@@ -42,8 +42,8 @@
 
   <ItemGroup>
     <PackageReference Include="DiffLib" Version="2017.7.26.1241" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.0.0-beta4-final" />
-    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.0.0-beta4-final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.3.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.3.1" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.13.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
     <PackageReference Include="NUnit" Version="3.11.0" />

ILSpy/AboutPage.cs

@@ -19,7 +19,6 @@
 using System;
 using System.ComponentModel;
 using System.ComponentModel.Composition;
-using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -129,20 +128,19 @@ namespace ICSharpCode.ILSpy
 			button.Cursor = Cursors.Arrow;
 			stackPanel.Children.Add(button);
 			
-			button.Click += delegate {
+			button.Click += async delegate {
 				button.Content = Resources.Checking;
 				button.IsEnabled = false;
-				GetLatestVersionAsync().ContinueWith(
-					delegate (Task<AvailableVersionInfo> task) {
+				
 				try {
+					AvailableVersionInfo vInfo = await GetLatestVersionAsync();
 					stackPanel.Children.Clear();
-							ShowAvailableVersion(task.Result, stackPanel);
+					ShowAvailableVersion(vInfo, stackPanel);
 				} catch (Exception ex) {
 					AvalonEditTextOutput exceptionOutput = new AvalonEditTextOutput();
 					exceptionOutput.WriteLine(ex.ToString());
 					textView.ShowText(exceptionOutput);
 				}
-					}, TaskScheduler.FromCurrentSynchronizationContext());
 			};
 		}
 		
@@ -183,36 +181,25 @@ namespace ICSharpCode.ILSpy
 			}
 		}
 		
-		static Task<AvailableVersionInfo> GetLatestVersionAsync()
+		static async Task<AvailableVersionInfo> GetLatestVersionAsync()
 		{
-			var tcs = new TaskCompletionSource<AvailableVersionInfo>();
-			new Action(() => {
 			WebClient wc = new WebClient();
 			IWebProxy systemWebProxy = WebRequest.GetSystemWebProxy();
 			systemWebProxy.Credentials = CredentialCache.DefaultCredentials;
 			wc.Proxy = systemWebProxy;
-				wc.DownloadDataCompleted += delegate(object sender, DownloadDataCompletedEventArgs e) {
-					if (e.Error != null) {
-						tcs.SetException(e.Error);
-					} else {
-						try {
-							XDocument doc = XDocument.Load(new MemoryStream(e.Result));
+
+			string data = await wc.DownloadStringTaskAsync(UpdateUrl);
+
+			XDocument doc = XDocument.Load(new StringReader(data));
 			var bands = doc.Root.Elements("band");
 			var currentBand = bands.FirstOrDefault(b => (string)b.Attribute("id") == band) ?? bands.First();
 			Version version = new Version((string)currentBand.Element("latestVersion"));
 			string url = (string)currentBand.Element("downloadUrl");
 			if (!(url.StartsWith("http://", StringComparison.Ordinal) || url.StartsWith("https://", StringComparison.Ordinal)))
 				url = null; // don't accept non-urls
+
 			latestAvailableVersion = new AvailableVersionInfo { Version = version, DownloadUrl = url };
-							tcs.SetResult(latestAvailableVersion);
-						} catch (Exception ex) {
-							tcs.SetException(ex);
-						}
-					}
-				};
-				wc.DownloadDataAsync(UpdateUrl);
-			}).BeginInvoke(null, null);
-			return tcs.Task;
+			return latestAvailableVersion;
 		}
 		
 		sealed class AvailableVersionInfo
@@ -274,9 +261,7 @@ namespace ICSharpCode.ILSpy
 			
 			void OnPropertyChanged(string propertyName)
 			{
-				if (PropertyChanged != null) {
-					PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
-				}
+				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
 			}
 		}
 		
@@ -285,10 +270,10 @@ namespace ICSharpCode.ILSpy
 		/// Returns the download URL if an update is available.
 		/// Returns null if no update is available, or if no check was performed.
 		/// </summary>
-		public static Task<string> CheckForUpdatesIfEnabledAsync(ILSpySettings spySettings)
+		public static async Task<string> CheckForUpdatesIfEnabledAsync(ILSpySettings spySettings)
 		{
-			var tcs = new TaskCompletionSource<string>();
 			UpdateSettings s = new UpdateSettings(spySettings);
+
 			// If we're in an MSIX package, updates work differently
 			if (s.AutomaticUpdateCheckEnabled && !WindowsVersionHelper.HasPackageIdentity) {
 				// perform update check if we never did one before;
@@ -297,40 +282,34 @@ namespace ICSharpCode.ILSpy
 				    || s.LastSuccessfulUpdateCheck < DateTime.UtcNow.AddDays(-7)
 				    || s.LastSuccessfulUpdateCheck > DateTime.UtcNow)
 				{
-					CheckForUpdateInternal(tcs, s);
+					return await CheckForUpdateInternal(s);
 				} else {
-					tcs.SetResult(null);
+					return null;
 				}
 			} else {
-				tcs.SetResult(null);
+				return null;
 			}
-			return tcs.Task;
 		}
 
 		public static Task<string> CheckForUpdatesAsync(ILSpySettings spySettings)
 		{
-			var tcs = new TaskCompletionSource<string>();
 			UpdateSettings s = new UpdateSettings(spySettings);
-			CheckForUpdateInternal(tcs, s);
-			return tcs.Task;
+			return CheckForUpdateInternal(s);
 		}
 
-		static void CheckForUpdateInternal(TaskCompletionSource<string> tcs, UpdateSettings s)
+		static async Task<string> CheckForUpdateInternal(UpdateSettings s)
 		{
-			GetLatestVersionAsync().ContinueWith(
-				delegate (Task<AvailableVersionInfo> task) {
 			try {
+				var v = await GetLatestVersionAsync();
 				s.LastSuccessfulUpdateCheck = DateTime.UtcNow;
-						AvailableVersionInfo v = task.Result;
 				if (v.Version > currentVersion)
-							tcs.SetResult(v.DownloadUrl);
+					return v.DownloadUrl;
 				else
-							tcs.SetResult(null);
-					} catch (AggregateException) {
+					return null;
+			} catch (Exception) {
 				// ignore errors getting the version info
-						tcs.SetResult(null);
+				return null;
 			}
-				});
 		}
 	}
 	

ILSpy/Analyzers/AnalyzerTreeView.cs

@@ -73,7 +73,7 @@ namespace ICSharpCode.ILSpy.Analyzers
 		public void Show()
 		{
 			if (!IsVisible)
-				MainWindow.Instance.ShowInBottomPane("Analyzer", this);
+				MainWindow.Instance.ShowInNewPane("Analyzer", this, PanePosition.Bottom);
 		}
 
 		public void Show(AnalyzerTreeNode node)

ILSpy/Analyzers/RemoveAnalyzeContextMenuEntry.cs

@@ -20,7 +20,7 @@ using System.Linq;
 
 namespace ICSharpCode.ILSpy.Analyzers
 {
-	[ExportContextMenuEntry(Header = "Remove", Icon = "images/Delete.png", Category = "Analyze", Order = 200)]
+	[ExportContextMenuEntry(Header = "Remove", Icon = "images/Delete", Category = "Analyze", Order = 200)]
 	internal sealed class RemoveAnalyzeContextMenuEntry : IContextMenuEntry
 	{
 		public bool IsVisible(TextViewContext context)

ILSpy/App.xaml.cs

@@ -94,7 +94,7 @@ namespace ICSharpCode.ILSpy
 						var name = Path.GetFileNameWithoutExtension(plugin);
 						try {
 							var asm = Assembly.Load(name);
-							var parts = discovery.CreatePartsAsync(asm).Result;
+							var parts = discovery.CreatePartsAsync(asm).GetAwaiter().GetResult();
 							catalog = catalog.AddParts(parts);
 						} catch (Exception ex) {
 							StartupExceptions.Add(new ExceptionData { Exception = ex, PluginName = name });
@@ -102,7 +102,7 @@ namespace ICSharpCode.ILSpy
 					}
 				}
 				// Add the built-in parts
-				catalog = catalog.AddParts(discovery.CreatePartsAsync(Assembly.GetExecutingAssembly()).Result);
+				catalog = catalog.AddParts(discovery.CreatePartsAsync(Assembly.GetExecutingAssembly()).GetAwaiter().GetResult());
 				// If/When the project switches to .NET Standard/Core, this will be needed to allow metadata interfaces (as opposed
 				// to metadata classes). When running on .NET Framework, it's automatic.
 				//   catalog.WithDesktopSupport();

ILSpy/Commands/CheckForUpdatesCommand.cs

@@ -34,9 +34,9 @@ namespace ICSharpCode.ILSpy
 			return base.CanExecute(parameter);
 		}
 
-		public override void Execute(object parameter)
+		public override async void Execute(object parameter)
 		{
-			MainWindow.Instance.ShowMessageIfUpdatesAvailableAsync(ILSpySettings.Load(), forceCheck: true);
+			await MainWindow.Instance.ShowMessageIfUpdatesAvailableAsync(ILSpySettings.Load(), forceCheck: true);
 		}
 	}
 }

ILSpy/Commands/DecompileInNewViewCommand.cs

@@ -0,0 +1,52 @@
+// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Linq;
+using ICSharpCode.ILSpy.Properties;
+using ICSharpCode.ILSpy.TextView;
+using ICSharpCode.ILSpy.TreeNodes;
+
+namespace ICSharpCode.ILSpy.Commands
+{
+	// [ExportContextMenuEntry(Header = nameof(Resources.DecompileToNewPanel), Icon = "images/Search", Category = nameof(Resources.Analyze), Order = 90)]
+	internal sealed class DecompileInNewViewCommand : IContextMenuEntry
+	{
+		public bool IsVisible(TextViewContext context)
+		{
+			if (context.SelectedTreeNodes == null)
+				return false;
+			return true;			
+		}
+
+		public bool IsEnabled(TextViewContext context)
+		{
+			if (context.SelectedTreeNodes == null)
+				return false;
+			return true;			
+		}
+
+		public async void Execute(TextViewContext context)
+		{
+			var dtv = new DecompilerTextView();
+			var nodes = context.SelectedTreeNodes.Cast<ILSpyTreeNode>().ToArray();
+			var title = string.Join(", ", nodes.Select(x => x.ToString()));
+			MainWindow.Instance.ShowInNewPane(title, dtv, PanePosition.Document);
+			await dtv.DecompileAsync(MainWindow.Instance.CurrentLanguage, nodes, new DecompilationOptions());
+		}
+	}
+}

ILSpy/ContextMenuEntry.cs

@@ -78,7 +78,7 @@ namespace ICSharpCode.ILSpy
 			if (textView != null)
 				reference = textView.GetReferenceSegmentAtMousePosition();
 			else if (listBox?.SelectedItem is SearchResult result)
-				reference = new ReferenceSegment { Reference = result.Member };
+				reference = new ReferenceSegment { Reference = result.Reference };
 			else
 				reference = null;
 			var position = textView != null ? textView.GetPositionFromMousePosition() : null;
@@ -222,16 +222,12 @@ namespace ICSharpCode.ILSpy
 						menuItem.Header = MainWindow.GetResourceString( entryPair.Metadata.Header);
 						menuItem.InputGestureText = entryPair.Metadata.InputGestureText;
 						if (!string.IsNullOrEmpty(entryPair.Metadata.Icon)) {
-							object image = Images.Load(entryPair.Value, entryPair.Metadata.Icon);
-							if (!(image is Viewbox)) {
-								image = new Image {
+							menuItem.Icon = new Image {
 								Width = 16,
 								Height = 16,
-									Source = (ImageSource)image
+								Source = Images.Load(entryPair.Value, entryPair.Metadata.Icon)
 							};
 						}
-							menuItem.Icon = image;
-						}
 						if (entryPair.Value.IsEnabled(context)) {
 							menuItem.Click += delegate { entry.Execute(context); };
 						} else

ILSpy/Controls/DockedPane.cs

@@ -1,76 +0,0 @@
-// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
-// 
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-// 
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-using System;
-using System.Windows;
-using System.Windows.Controls;
-using System.Windows.Input;
-
-namespace ICSharpCode.ILSpy.Controls
-{
-	class DockedPane : Control
-	{
-		static DockedPane()
-		{
-			DefaultStyleKeyProperty.OverrideMetadata(typeof(DockedPane), new FrameworkPropertyMetadata(typeof(DockedPane)));
-		}
-		
-		public static readonly DependencyProperty TitleProperty =
-			DependencyProperty.Register("Title", typeof(string), typeof(DockedPane));
-		
-		public string Title {
-			get { return (string)GetValue(TitleProperty); }
-			set { SetValue(TitleProperty, value); }
-		}
-		
-		public static readonly DependencyProperty ContentProperty =
-			DependencyProperty.Register("Content", typeof(object), typeof(DockedPane));
-		
-		public object Content {
-			get { return GetValue(ContentProperty); }
-			set { SetValue(ContentProperty, value); }
-		}
-		
-		public override void OnApplyTemplate()
-		{
-			base.OnApplyTemplate();
-			Button closeButton = (Button)this.Template.FindName("PART_Close", this);
-			if (closeButton != null) {
-				closeButton.Click += closeButton_Click;
-			}
-		}
-		
-		void closeButton_Click(object sender, RoutedEventArgs e)
-		{
-			if (CloseButtonClicked != null)
-				CloseButtonClicked(this, e);
-		}
-		
-		public event EventHandler CloseButtonClicked;
-		
-		protected override void OnKeyDown(KeyEventArgs e)
-		{
-			base.OnKeyDown(e);
-			if (e.Key == Key.F4 && e.KeyboardDevice.Modifiers == ModifierKeys.Control || e.Key == Key.Escape) {
-				if (CloseButtonClicked != null)
-					CloseButtonClicked(this, e);
-				e.Handled = true;
-			}
-		}
-	}
-}

ILSpy/DebugSteps.xaml.cs

@@ -79,7 +79,7 @@ namespace ICSharpCode.ILSpy
 
 		public static void Show()
 		{
-			MainWindow.Instance.ShowInTopPane(Properties.Resources.DebugSteps, new DebugSteps());
+			MainWindow.Instance.ShowInNewPane(Properties.Resources.DebugSteps, new DebugSteps(), PanePosition.Top);
 		}
 
 		void IPane.Closed()

ILSpy/Docking/DockLayoutSettings.cs

@@ -0,0 +1,50 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Xml;
+using System.Xml.Linq;
+using Xceed.Wpf.AvalonDock.Layout.Serialization;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class DockLayoutSettings
+	{
+		private string rawSettings;
+
+		public bool Valid => rawSettings != null;
+
+		public DockLayoutSettings(XElement element)
+		{
+			if ((element != null) && element.HasElements) {
+				rawSettings = element.Elements().FirstOrDefault()?.ToString();
+			}
+		}
+
+		public XElement SaveAsXml()
+		{
+			try {
+				return XElement.Parse(rawSettings);
+			} catch (Exception) {
+				return null;
+			}
+		}
+
+		public void Deserialize(XmlLayoutSerializer serializer)
+		{
+			if (!Valid)
+				return;
+
+			using (StringReader reader = new StringReader(rawSettings)) {
+				serializer.Deserialize(reader);
+			}
+		}
+
+		public void Serialize(XmlLayoutSerializer serializer)
+		{
+			using (StringWriter fs = new StringWriter()) {
+				serializer.Serialize(fs);
+				rawSettings = fs.ToString();
+			}
+		}
+	}
+}

ILSpy/Docking/DockingHelper.cs

@@ -0,0 +1,32 @@
+using System.Windows;
+using System.Windows.Controls;
+using Xceed.Wpf.AvalonDock.Layout;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public static class DockingHelper
+	{
+		public static void DockHorizontal(LayoutContent layoutContent, ILayoutElement paneRelativeTo, GridLength dockHeight, bool dockBefore = false)
+		{
+			if (paneRelativeTo is ILayoutDocumentPane parentDocumentPane) {
+				var parentDocumentGroup = paneRelativeTo.FindParent<LayoutDocumentPaneGroup>();
+				if (parentDocumentGroup == null) {
+					var grandParent = parentDocumentPane.Parent as ILayoutContainer;
+					parentDocumentGroup = new LayoutDocumentPaneGroup() { Orientation = System.Windows.Controls.Orientation.Vertical };
+					grandParent.ReplaceChild(paneRelativeTo, parentDocumentGroup);
+					parentDocumentGroup.Children.Add(parentDocumentPane);
+				}
+				parentDocumentGroup.Orientation = System.Windows.Controls.Orientation.Vertical;
+				int indexOfParentPane = parentDocumentGroup.IndexOfChild(parentDocumentPane);
+				var layoutDocumentPane = new LayoutDocumentPane(layoutContent) { DockHeight = dockHeight };
+				parentDocumentGroup.InsertChildAt(dockBefore ? indexOfParentPane : indexOfParentPane + 1, layoutDocumentPane);
+				layoutContent.IsActive = true;
+				layoutContent.Root.CollectGarbage();
+				Application.Current.MainWindow.Dispatcher.Invoke(() => {
+
+					layoutDocumentPane.DockHeight = dockHeight;
+				}, System.Windows.Threading.DispatcherPriority.Loaded);
+			}
+		}
+	}
+}

ILSpy/Docking/PanePosition.cs

@@ -0,0 +1,9 @@
+namespace ICSharpCode.ILSpy
+{
+	public enum PanePosition
+	{
+		Top,
+		Bottom,
+		Document
+	}
+}

ILSpy/ILSpy.csproj

@@ -49,8 +49,10 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="AvalonEdit" Version="6.0.0-rc1" />
-    <PackageReference Include="Microsoft.VisualStudio.Composition" Version="15.5.23" />
+    <PackageReference Include="AvalonEdit" Version="6.0.0" />
+    <PackageReference Include="Dirkster.AvalonDock" Version="3.5.12" />
+    <PackageReference Include="Microsoft.VisualStudio.Composition" Version="16.3.7" />
+    <PackageReference Include="System.Composition" Version="1.3.0" />
     <PackageReference Include="Mono.Cecil" Version="0.10.3" />
     <PackageReference Include="OSVersionHelper" Version="1.0.11" />
   </ItemGroup>
@@ -100,6 +102,7 @@
     <Compile Include="AssemblyListManager.cs" />
     <Compile Include="AvalonEdit\ITextMarker.cs" />
     <Compile Include="AvalonEdit\TextMarkerService.cs" />
+    <Compile Include="Commands\DecompileInNewViewCommand.cs" />
     <Compile Include="Commands\CheckForUpdatesCommand.cs" />
     <Compile Include="Commands\BrowseBackCommand.cs" />
     <Compile Include="Commands\BrowseForwardCommand.cs" />
@@ -123,7 +126,6 @@
     <Compile Include="Controls\ResourceObjectTable.xaml.cs">
       <DependentUpon>ResourceObjectTable.xaml</DependentUpon>
     </Compile>
-    <Compile Include="Controls\DockedPane.cs" />
     <Compile Include="Commands\DecompileAllCommand.cs" />
     <Compile Include="Commands\ExportCommandAttribute.cs" />
     <Compile Include="Controls\ExtensionMethods.cs" />
@@ -137,6 +139,8 @@
     <Compile Include="DebugSteps.xaml.cs">
       <DependentUpon>DebugSteps.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Docking\DockingHelper.cs" />
+    <Compile Include="Docking\DockLayoutSettings.cs" />
     <Compile Include="ILSpyTraceListener.cs" />
     <Compile Include="DecompilationOptions.cs" />
     <Compile Include="ExtensionMethods.cs" />
@@ -163,11 +167,14 @@
     <Compile Include="Languages\Language.cs" />
     <Compile Include="Languages\Languages.cs" />
     <Compile Include="Options\DecompilerSettingsPanel.xaml.cs" />
+    <Compile Include="Docking\PanePosition.cs" />
     <Compile Include="Properties\Resources.Designer.cs">
       <DesignTime>True</DesignTime>
       <AutoGen>True</AutoGen>
       <DependentUpon>Resources.resx</DependentUpon>
     </Compile>
+    <Compile Include="Search\AbstractEntitySearchStrategy.cs" />
+    <Compile Include="Search\AssemblySearchStrategy.cs" />
     <Compile Include="Search\LiteralSearchStrategy.cs" />
     <Compile Include="LoadedAssembly.cs" />
     <Compile Include="LoadedAssemblyExtensions.cs" />
@@ -205,11 +212,13 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Commands\RefreshCommand.cs" />
     <Compile Include="Commands\SaveCommand.cs" />
+    <Compile Include="Search\ResourceSearchStrategy.cs" />
     <Compile Include="Search\SearchPane.cs">
       <DependentUpon>SearchPane.xaml</DependentUpon>
     </Compile>
     <Compile Include="Commands\SimpleCommand.cs" />
     <Compile Include="Search\AbstractSearchStrategy.cs" />
+    <Compile Include="Search\SearchResult.cs" />
     <Compile Include="SolutionWriter.cs" />
     <Compile Include="TaskHelper.cs" />
     <Compile Include="TextView\BracketHighlightRenderer.cs" />

ILSpy/Images/Copy.xaml

@@ -1,20 +1,10 @@
 <!-- This file was generated by the AiToXaml tool.-->
 <!-- Tool Version: 14.0.22307.0 -->
-<Viewbox Width="16" Height="16" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
-  <Rectangle Width="16" Height="16">
-    <Rectangle.Fill>
-      <DrawingBrush>
-        <DrawingBrush.Drawing>
-          <DrawingGroup>
+<DrawingGroup xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 	<DrawingGroup.Children>
 		<GeometryDrawing Brush="#00FFFFFF" Geometry="F1M16,16L0,16 0,0 16,0z" />
 		<GeometryDrawing Brush="#FFF6F6F6" Geometry="F1M0.9999,-0.000199999999999534L0.9999,13.0008 5.0009,13.0008 5.0009,15.9998 15.9999,15.9998 15.9999,7.3788 11.6209,3.0008 10.6049,3.0008 7.6179,-0.000199999999999534z" />
 		<GeometryDrawing Brush="#FF424242" Geometry="F1M14,14L7,14 7,5 10,5 10,9 14,9z M6,11L3,11 3,2 6.798,2 8.81,4 6,4z M11,5.207L13.793,8 11,8z M11.207,4L10.19,4 7.202,1 2,1 2,12 6,12 6,15 15,15 15,7.793z" />
 		<GeometryDrawing Brush="#FFF0EFF1" Geometry="F1M14,14L7,14 7,5 10,5 10,9 14,9z M6,11L3,11 3,2 6.798,2 8.81,4 6,4z M11,5.207L13.793,8 11,8z" />
 	</DrawingGroup.Children>
-          </DrawingGroup>
-        </DrawingBrush.Drawing>
-      </DrawingBrush>
-    </Rectangle.Fill>
-  </Rectangle>
-</Viewbox>
+</DrawingGroup>

ILSpy/Images/README.md

@@ -14,7 +14,7 @@ Icons used in ILSpy:
 | Constructor               |  x  |  x   | based on VS 2017 Icon Pack (Method) using a different colour                    |         |
 | Copy                      |  x  |  x   | VS 2017 Icon Pack (Copy)                                                        |         |
 | Delegate                  |  x  |  x   | VS 2017 Icon Pack (Delegate)                                                    |         |
-| Delete                    |  x  |  x   |                                                                                 |         |
+| Delete                    |  x  |  x   | VS 2017 Icon Pack (Remove_color)                                                |         |
 | Enum                      |  x  |  x   | VS 2017 Icon Pack (Enumerator)                                                  |         |
 | EnumValue                 |  x  |  x   | VS 2017 Icon Pack (EnumItem)                                                    |         |
 | Event                     |  x  |  x   | VS 2017 Icon Pack (Event)                                                       |         |
@@ -45,10 +45,10 @@ Icons used in ILSpy:
 | Property                  |  x  |  x   | VS 2017 Icon Pack (Property)                                                    |         |
 | ReferenceFolder           |  x  |  x   | combined VS 2017 Icon Pack (Reference) two times                                |         |
 | Refresh                   |  x  |  x   | VS 2017 Icon Pack (Refresh)                                                     |         |
-| Resource                  |  x  |  x   |                                                                                 |         |
-| ResourceImage             |  x  |  x   |                                                                                 |         |
-| ResourceResourcesFile     |  x  |  x   |                                                                                 |         |
-| ResourceXml               |  x  |  x   |                                                                                 |         |
+| Resource                  |  x  |  x   | VS 2017 Icon Pack (Document)                                                    |         |
+| ResourceImage             |  x  |  x   | VS 2017 Icon Pack (Image)                                                       |         |
+| ResourceResourcesFile     |  x  |  x   | VS 2017 Icon Pack (LocalResources)                                              |         |
+| ResourceXml               |  x  |  x   | VS 2017 Icon Pack (XMLFile)                                                     |         |
 | ResourceXsd               |  x  |  x   | combined VS 2017 Icon Pack (XMLSchema) with the "file symbol in ResourceXslt    |         |
 | ResourceXsl               |  x  |  x   | VS 2017 Icon Pack (XMLTransformation)                                           |         |
 | ResourceXslt              |  x  |  x   | VS 2017 Icon Pack (XSLTTemplate)                                                |         |
@@ -57,12 +57,12 @@ Icons used in ILSpy:
 | SearchMsdn                |  x  |  x   | based on VS 2017 Icon Pack (Search) + Microsoft Logo                            |         |
 | ShowAll                   |  x  |  x   | combined PublicOnly, OverlayPrivate, OverlayProtected, OverlayInternal          |         |
 | ShowPrivateInternal       |  x  |  x   | combined OverlayPrivate and OverlayInternal                                     |         |
-| ShowPublicOnly            |  x  |  x   |                                                                                 |         |
+| ShowPublicOnly            |  x  |  x   | VS 2017 Icon Pack (Type)                                                        |         |
 | Sort                      |  x  |  x   | VS 2017 Icon Pack (SortAscending)                                               |         |
 | Struct                    |  x  |  x   | VS 2017 Icon Pack (Structure)                                                   |         |
-| SubTypes                  |  x  |  x   |                                                                                 |         |
-| SuperTypes                |  x  |  x   |                                                                                 |         |
-| ViewCode                  |  x  |  x   |                                                                                 |         |
+| SubTypes                  |  x  |  x   | based on VS 2017 Icon Pack (BaseType) rotated +90°                              |         |
+| SuperTypes                |  x  |  x   | based on VS 2017 Icon Pack (BaseType) rotated -90°                              |         |
+| ViewCode                  |  x  |  x   | VS 2017 Icon Pack (GoToSourceCode)                                              |         |
 | VirtualMethod             |  x  |  x   | combined VS 2017 Icon Pack (Method) two times                                   |         |
 | Warning                   |  x  |  x   | VS 2017 Icon Pack (StatusWarning)                                               |         |
 

ILSpy/Languages/CSharpHighlightingTokenWriter.cs

@@ -194,7 +194,6 @@ namespace ICSharpCode.ILSpy
 				case "event":
 				case "extern":
 				case "override":
-				case "readonly":
 				case "sealed":
 				case "static":
 				case "virtual":
@@ -203,6 +202,12 @@ namespace ICSharpCode.ILSpy
 				case "partial":
 					color = modifiersColor;
 					break;
+				case "readonly":
+					if (role == ComposedType.ReadonlyRole)
+						color = parameterModifierColor;
+					else
+						color = modifiersColor;
+					break;
 				case "checked":
 				case "unchecked":
 					color = checkedKeywordColor;

ILSpy/LoadedAssembly.cs

@@ -87,7 +87,7 @@ namespace ICSharpCode.ILSpy
 		public PEFile GetPEFileOrNull()
 		{
 			try {
-				return GetPEFileAsync().Result;
+				return GetPEFileAsync().GetAwaiter().GetResult();
 			} catch (Exception ex) {
 				System.Diagnostics.Trace.TraceError(ex.ToString());
 				return null;

ILSpy/MainWindow.xaml

@@ -4,7 +4,7 @@
 	x:ClassModifier="public"
 	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:tv="clr-namespace:ICSharpCode.TreeView;assembly=ICSharpCode.TreeView"
 	xmlns:local="clr-namespace:ICSharpCode.ILSpy"
-	xmlns:textView="clr-namespace:ICSharpCode.ILSpy.TextView"
+	xmlns:avalondock="http://schemas.xceed.com/wpf/xaml/avalondock"
 	xmlns:controls="clr-namespace:ICSharpCode.ILSpy.Controls"
 	xmlns:properties="clr-namespace:ICSharpCode.ILSpy.Properties"	
 	Title="ILSpy"
@@ -51,7 +51,8 @@
 	<DockPanel>
 		<!-- Main menu -->
 		<Menu DockPanel.Dock="Top" Name="mainMenu" Height="23" KeyboardNavigation.TabNavigation="None">
-			<MenuItem Header="{x:Static properties:Resources._File}" /> <!-- contents of file menu are added using MEF -->
+			<MenuItem Header="{x:Static properties:Resources._File}" />
+			<!-- contents of file menu are added using MEF -->
 			<MenuItem Header="{x:Static properties:Resources._View}">
 				<MenuItem Header="{x:Static properties:Resources.Show_publiconlyTypesMembers}" IsCheckable="True" IsChecked="{Binding FilterSettings.ApiVisPublicOnly}" />
 				<MenuItem Header="{x:Static properties:Resources.Show_internalTypesMembers}" IsCheckable="True" IsChecked="{Binding FilterSettings.ApiVisPublicAndInternal}" />
@@ -96,6 +97,15 @@
 			          ItemsSource="{Binding SelectedItem.LanguageVersions, ElementName=languageComboBox, UpdateSourceTrigger=PropertyChanged}"
 			          SelectedItem="{Binding FilterSettings.LanguageVersion, UpdateSourceTrigger=PropertyChanged}"/>
 		</ToolBar>
+		<Border DockPanel.Dock="Top" BorderBrush="Black" BorderThickness="1" Name="updatePanel" Visibility="Collapsed">
+			<DockPanel KeyboardNavigation.TabNavigation="Contained">
+				<Button DockPanel.Dock="Right" Click="updatePanelCloseButtonClick" MinWidth="0">X</Button>
+				<StackPanel Orientation="Horizontal">
+					<TextBlock Name="updatePanelMessage" Margin="4,0" VerticalAlignment="Center"  Text="{x:Static properties:Resources.ILSpyVersionAvailable}" />
+					<Button Name="downloadOrCheckUpdateButton" Click="downloadOrCheckUpdateButtonClick" Content="{x:Static properties:Resources.Download}"/>
+				</StackPanel>
+			</DockPanel>
+		</Border>
 		<!-- Status bar -->
 		<StatusBar x:Name="statusBar" DockPanel.Dock="Bottom" Height="26" Visibility="Collapsed">
 			<StatusBarItem DockPanel.Dock="Right">
@@ -107,23 +117,16 @@
 			</StatusBarItem>
 		</StatusBar>
 		<!-- Main grid separating left pane (treeView) from main pane (textEditor) -->
-		<Grid>
-			<Grid.ColumnDefinitions>
-				<ColumnDefinition
-					Name="leftColumn"
-					MinWidth="100"
-					Width="0.4*" />
-				<ColumnDefinition
-					Width="3" />
-				<ColumnDefinition
-					Name="rightColumn"
-					MinWidth="100"
-					Width="0.6*" />
-			</Grid.ColumnDefinitions>
-			<Grid.RowDefinitions>
-				<RowDefinition
-					Height="*" />
-			</Grid.RowDefinitions>
+
+		<avalondock:DockingManager x:Name="DockManager"
+                    AllowMixedOrientation="True" Grid.ColumnSpan="2">
+
+			<avalondock:LayoutRoot x:Name="LayoutRoot" >
+				<avalondock:LayoutPanel Orientation="Vertical">
+					<avalondock:LayoutPanel Orientation="Horizontal">
+						<avalondock:LayoutAnchorablePaneGroup DockWidth="400" Orientation="Vertical">
+							<avalondock:LayoutAnchorablePane DockHeight="*">
+								<avalondock:LayoutAnchorable x:Name="Tree" Title="Assemblies" CanHide="False" CanClose="False">
 									<!-- Left pane: Tree View of assemblies and classes -->
 									<tv:SharpTreeView
 										Name="treeView"
@@ -133,73 +136,21 @@
 										AllowDropOrder="True"
 										AllowDrop="True"
 										BorderThickness="0,1,1,1" Visibility="Visible" />
-			<GridSplitter
-				Grid.ZIndex="1"
-				Grid.Column="1"
-				Margin="-5,0"
-				BorderThickness="5,0"
-				HorizontalAlignment="Center"
-				VerticalAlignment="Stretch"
-				Focusable="False"
-				BorderBrush="Transparent" />
-			<!-- Right pane: Text Editor -->
-			<Grid Grid.Column="2">
-				<Grid.ColumnDefinitions>
-					<ColumnDefinition
-						Width="*" />
-				</Grid.ColumnDefinitions>
-				<Grid.RowDefinitions>
-					<RowDefinition Height="Auto" />
-					<RowDefinition Height="0" Name="topPaneRow" />
-					<RowDefinition Height="0" />
-					<RowDefinition Height="0.7*" MinHeight="100" Name="textViewRow" />
-					<RowDefinition Height="0" />
-					<RowDefinition Height="0" Name="bottomPaneRow" />
-				</Grid.RowDefinitions>
-				<Border BorderBrush="Black" BorderThickness="1" Name="updatePanel" Visibility="Collapsed">
-					<DockPanel KeyboardNavigation.TabNavigation="Contained">
-						<Button DockPanel.Dock="Right" Click="updatePanelCloseButtonClick" MinWidth="0">X</Button>
-						<StackPanel Orientation="Horizontal">
-							<TextBlock Name="updatePanelMessage" Margin="4,0" VerticalAlignment="Center"  Text="{x:Static properties:Resources.ILSpyVersionAvailable}" />
-							<Button Name="downloadOrCheckUpdateButton" Click="downloadOrCheckUpdateButtonClick" Content="{x:Static properties:Resources.Download}"/>
-						</StackPanel>
-					</DockPanel>
-				</Border>
-				
-				<controls:DockedPane x:Name="topPane" Grid.Row="1" Title="Top" Visibility="Collapsed"
-									 AutomationProperties.Name="Close top pane"
-					CloseButtonClicked="TopPane_CloseButtonClicked" Margin="0,0,0,3"
-					BorderThickness="1,1,0,1" />
-				
-				<GridSplitter
-					Grid.ZIndex="1"
-					Grid.Row="2"
-					Margin="0,-2,0,-5"
-					BorderThickness="0,2,0,5"
-					BorderBrush="Transparent"
-					HorizontalAlignment="Stretch"
-					VerticalAlignment="Center"
-					Focusable="False"
-					Visibility="{Binding Visibility, ElementName=topPane}" />
+								</avalondock:LayoutAnchorable>
+							</avalondock:LayoutAnchorablePane>
+						</avalondock:LayoutAnchorablePaneGroup>
 
+						<avalondock:LayoutDocumentPaneGroup DockWidth="*">
+							<avalondock:LayoutDocumentPane x:Name="adDocumentPane">
+								<avalondock:LayoutDocument Title="View" CanClose="False">
 									<!-- decompilerTextView is into the mainPane by code -->
-				<ContentPresenter Name="mainPane" Grid.Row="3"/>
-				
-				<GridSplitter
-					Grid.ZIndex="1"
-					Grid.Row="4"
-					Margin="0,-2,0,-5"
-					BorderThickness="0,2,0,5"
-					BorderBrush="Transparent"
-					HorizontalAlignment="Stretch"
-					VerticalAlignment="Center"
-					Focusable="False"
-					Visibility="{Binding Visibility, ElementName=bottomPane}" />
-				
-				<controls:DockedPane x:Name="bottomPane" Grid.Row="5" Title="Bottom" Visibility="Collapsed"
-									 AutomationProperties.Name="Close"
-					CloseButtonClicked="BottomPane_CloseButtonClicked" Margin="0,3,0,0" BorderThickness="1,1,0,1"/>
-			</Grid>
-		</Grid>
+									<ContentPresenter Name="mainPane" />
+								</avalondock:LayoutDocument>
+							</avalondock:LayoutDocumentPane>
+						</avalondock:LayoutDocumentPaneGroup>
+					</avalondock:LayoutPanel>
+				</avalondock:LayoutPanel>
+			</avalondock:LayoutRoot>
+		</avalondock:DockingManager>
 	</DockPanel>
 </Window>

ILSpy/MainWindow.xaml.cs

@@ -44,6 +44,8 @@ using ICSharpCode.ILSpy.TreeNodes;
 using ICSharpCode.TreeView;
 using Microsoft.Win32;
 using OSVersionHelper;
+using Xceed.Wpf.AvalonDock.Layout;
+using Xceed.Wpf.AvalonDock.Layout.Serialization;
 
 namespace ICSharpCode.ILSpy
 {
@@ -90,10 +92,8 @@ namespace ICSharpCode.ILSpy
 			decompilerTextView = App.ExportProvider.GetExportedValue<DecompilerTextView>();
 			mainPane.Content = decompilerTextView;
 
-			if (sessionSettings.SplitterPosition > 0 && sessionSettings.SplitterPosition < 1) {
-				leftColumn.Width = new GridLength(sessionSettings.SplitterPosition, GridUnitType.Star);
-				rightColumn.Width = new GridLength(1 - sessionSettings.SplitterPosition, GridUnitType.Star);
-			}
+			sessionSettings.DockLayout.Deserialize(new XmlLayoutSerializer(DockManager));
+
 			sessionSettings.FilterSettings.PropertyChanged += filterSettings_PropertyChanged;
 
 			InitMainMenu();
@@ -140,19 +140,15 @@ namespace ICSharpCode.ILSpy
 
 		Button MakeToolbarItem(Lazy<ICommand, IToolbarCommandMetadata> command)
 		{
-			object image = Images.Load(command.Value, command.Metadata.ToolbarIcon);
-			if (!(image is Viewbox)) {
-				image = new Image {
-					Width = 16,
-					Height = 16,
-					Source = (ImageSource)image
-				};
-			}
 			return new Button {
 				Command = CommandWrapper.Unwrap(command.Value),
 				ToolTip = Properties.Resources.ResourceManager.GetString(command.Metadata.ToolTip),
 				Tag = command.Metadata.Tag,
-				Content = image
+				Content = new Image {
+					Width = 16,
+					Height = 16,
+					Source = Images.Load(command.Value, command.Metadata.ToolbarIcon)
+				}
 			};
 		}
 		#endregion
@@ -178,16 +174,12 @@ namespace ICSharpCode.ILSpy
 						if (!string.IsNullOrEmpty(GetResourceString(entry.Metadata.Header)))
 							menuItem.Header = GetResourceString(entry.Metadata.Header);
 						if (!string.IsNullOrEmpty(entry.Metadata.MenuIcon)) {
-							object image = Images.Load(entry.Value, entry.Metadata.MenuIcon);
-							if (!(image is Viewbox)) {
-								image = new Image {
+							menuItem.Icon = new Image {
 								Width = 16,
 								Height = 16,
-									Source = (ImageSource)image
+								Source = Images.Load(entry.Value, entry.Metadata.MenuIcon)
 							};
 						}
-							menuItem.Icon = image;
-						}
 
 						menuItem.IsEnabled = entry.Metadata.IsEnabled;
 						menuItem.InputGestureText = entry.Metadata.InputGestureText;
@@ -331,6 +323,10 @@ namespace ICSharpCode.ILSpy
 							}
 						}
 					}
+				} else if (navigateTo == "none") {
+					// Don't navigate anywhere; start empty.
+					// Used by ILSpy VS addin, it'll send us the real location to navigate to via IPC.
+					found = true;
 				} else {
 					IEntity mr = await Task.Run(() => FindEntityInRelevantAssemblies(navigateTo, relevantAssemblies));
 					if (mr != null && mr.ParentModule.PEFile != null) {
@@ -345,31 +341,31 @@ namespace ICSharpCode.ILSpy
 					output.Write(string.Format("Cannot find '{0}' in command line specified assemblies.", navigateTo));
 					decompilerTextView.ShowText(output);
 				}
-			} else if (commandLineLoadedAssemblies.Count == 1) {
+			} else if (relevantAssemblies.Count == 1) {
 				// NavigateTo == null and an assembly was given on the command-line:
 				// Select the newly loaded assembly
-				AssemblyTreeNode asmNode = assemblyListTreeNode.FindAssemblyNode(commandLineLoadedAssemblies[0]);
+				AssemblyTreeNode asmNode = assemblyListTreeNode.FindAssemblyNode(relevantAssemblies[0]);
 				if (asmNode != null && treeView.SelectedItem == initialSelection) {
 					SelectNode(asmNode);
 				}
 			} else if (spySettings != null) {
 				SharpTreeNode node = null;
-				if (sessionSettings.ActiveTreeViewPath?.Length > 0) {
+				if (activeTreeViewPath?.Length > 0) {
 					foreach (var asm in assemblyList.GetAssemblies()) {
-						if (asm.FileName == sessionSettings.ActiveTreeViewPath[0]) {
+						if (asm.FileName == activeTreeViewPath[0]) {
 							// FindNodeByPath() blocks the UI if the assembly is not yet loaded,
 							// so use an async wait instead.
 							await asm.GetPEFileAsync().Catch<Exception>(ex => { });
 						}
 					}
-					node = FindNodeByPath(sessionSettings.ActiveTreeViewPath, true);
+					node = FindNodeByPath(activeTreeViewPath, true);
 				}
 				if (treeView.SelectedItem == initialSelection) {
 					if (node != null) {
 						SelectNode(node);
 
 						// only if not showing the about page, perform the update check:
-						ShowMessageIfUpdatesAvailableAsync(spySettings);
+						await ShowMessageIfUpdatesAvailableAsync(spySettings);
 					} else {
 						AboutPage.Display(decompilerTextView);
 					}
@@ -503,20 +499,21 @@ namespace ICSharpCode.ILSpy
 		#region Update Check
 		string updateAvailableDownloadUrl;
 
-		public void ShowMessageIfUpdatesAvailableAsync(ILSpySettings spySettings, bool forceCheck = false)
+		public async Task ShowMessageIfUpdatesAvailableAsync(ILSpySettings spySettings, bool forceCheck = false)
 		{
 			// Don't check for updates if we're in an MSIX since they work differently
 			if (WindowsVersionHelper.HasPackageIdentity) {
 				return;
 			}
 
-			Task<string> result;
+			string downloadUrl;
 			if (forceCheck) {
-				result = AboutPage.CheckForUpdatesAsync(spySettings);
+				downloadUrl = await AboutPage.CheckForUpdatesAsync(spySettings);
 			} else {
-				result = AboutPage.CheckForUpdatesIfEnabledAsync(spySettings);
+				downloadUrl = await AboutPage.CheckForUpdatesIfEnabledAsync(spySettings);
 			}
-			result.ContinueWith(task => AdjustUpdateUIAfterCheck(task, forceCheck), TaskScheduler.FromCurrentSynchronizationContext());
+
+			AdjustUpdateUIAfterCheck(downloadUrl, forceCheck);
 		}
 
 		void updatePanelCloseButtonClick(object sender, RoutedEventArgs e)
@@ -524,22 +521,22 @@ namespace ICSharpCode.ILSpy
 			updatePanel.Visibility = Visibility.Collapsed;
 		}
 
-		void downloadOrCheckUpdateButtonClick(object sender, RoutedEventArgs e)
+		async void downloadOrCheckUpdateButtonClick(object sender, RoutedEventArgs e)
 		{
 			if (updateAvailableDownloadUrl != null) {
 				MainWindow.OpenLink(updateAvailableDownloadUrl);
 			} else {
 				updatePanel.Visibility = Visibility.Collapsed;
-				AboutPage.CheckForUpdatesAsync(ILSpySettings.Load())
-					.ContinueWith(task => AdjustUpdateUIAfterCheck(task, true), TaskScheduler.FromCurrentSynchronizationContext());
+				string downloadUrl = await AboutPage.CheckForUpdatesAsync(ILSpySettings.Load());
+				AdjustUpdateUIAfterCheck(downloadUrl, true);
 			}
 		}
 
-		void AdjustUpdateUIAfterCheck(Task<string> task, bool displayMessage)
+		void AdjustUpdateUIAfterCheck(string downloadUrl, bool displayMessage)
 		{
-			updateAvailableDownloadUrl = task.Result;
+			updateAvailableDownloadUrl = downloadUrl;
 			updatePanel.Visibility = displayMessage ? Visibility.Visible : Visibility.Collapsed;
-			if (task.Result != null) {
+			if (downloadUrl != null) {
 				updatePanelMessage.Text = Properties.Resources.ILSpyVersionAvailable;
 				downloadOrCheckUpdateButton.Content = Properties.Resources.Download;
 			} else {
@@ -713,6 +710,8 @@ namespace ICSharpCode.ILSpy
 					return assemblyListTreeNode.FindAssemblyNode(asm);
 				case Resource res:
 					return assemblyListTreeNode.FindResourceNode(res);
+				case ValueTuple<Resource, string> resName:
+					return assemblyListTreeNode.FindResourceNode(resName.Item1, resName.Item2);
 				case ITypeDefinition type:
 					return assemblyListTreeNode.FindTypeNode(type);
 				case IField fd:
@@ -1016,11 +1015,7 @@ namespace ICSharpCode.ILSpy
 			sessionSettings.ActiveTreeViewPath = GetPathForNode(treeView.SelectedItem as SharpTreeNode);
 			sessionSettings.ActiveAutoLoadedAssembly = GetAutoLoadedAssemblyNode(treeView.SelectedItem as SharpTreeNode);
 			sessionSettings.WindowBounds = this.RestoreBounds;
-			sessionSettings.SplitterPosition = leftColumn.Width.Value / (leftColumn.Width.Value + rightColumn.Width.Value);
-			if (topPane.Visibility == Visibility.Visible)
-				sessionSettings.TopPaneSplitterPosition = topPaneRow.Height.Value / (topPaneRow.Height.Value + textViewRow.Height.Value);
-			if (bottomPane.Visibility == Visibility.Visible)
-				sessionSettings.BottomPaneSplitterPosition = bottomPaneRow.Height.Value / (bottomPaneRow.Height.Value + textViewRow.Height.Value);
+			sessionSettings.DockLayout.Serialize(new XmlLayoutSerializer(DockManager));
 			sessionSettings.Save();
 		}
 
@@ -1042,95 +1037,19 @@ namespace ICSharpCode.ILSpy
 
 		#region Top/Bottom Pane management
 
-		/// <summary>
-		///   When grid is resized using splitter, row height value could become greater than 1.
-		///   As result, when a new pane is shown, both textView and pane could become very small.
-		///   This method normalizes two rows and ensures that height is less then 1.
-		/// </summary>
-		void NormalizePaneRowHeightValues(RowDefinition pane1Row, RowDefinition pane2Row)
-		{
-			var pane1Height = pane1Row.Height;
-			var pane2Height = pane2Row.Height;
-
-			//only star height values are normalized.
-			if (!pane1Height.IsStar || !pane2Height.IsStar) {
-				return;
-			}
-
-			var totalHeight = pane1Height.Value + pane2Height.Value;
-			if (totalHeight == 0) {
-				return;
-			}
-
-			pane1Row.Height = new GridLength(pane1Height.Value / totalHeight, GridUnitType.Star);
-			pane2Row.Height = new GridLength(pane2Height.Value / totalHeight, GridUnitType.Star);
-		}
-
-		public void ShowInTopPane(string title, object content)
-		{
-			topPaneRow.MinHeight = 100;
-			if (sessionSettings.TopPaneSplitterPosition > 0 && sessionSettings.TopPaneSplitterPosition < 1) {
-				//Ensure all 3 blocks are in fair conditions
-				NormalizePaneRowHeightValues(bottomPaneRow, textViewRow);
-
-				textViewRow.Height = new GridLength(1 - sessionSettings.TopPaneSplitterPosition, GridUnitType.Star);
-				topPaneRow.Height = new GridLength(sessionSettings.TopPaneSplitterPosition, GridUnitType.Star);
-			}
-			topPane.Title = title;
-			if (topPane.Content != content) {
-				IPane pane = topPane.Content as IPane;
-				if (pane != null)
-					pane.Closed();
-				topPane.Content = content;
-			}
-			topPane.Visibility = Visibility.Visible;
-		}
-
-		void TopPane_CloseButtonClicked(object sender, EventArgs e)
+		public void ShowInNewPane(string title, object content, PanePosition panePosition, string toolTip = null)
 		{
-			sessionSettings.TopPaneSplitterPosition = topPaneRow.Height.Value / (topPaneRow.Height.Value + textViewRow.Height.Value);
-			topPaneRow.MinHeight = 0;
-			topPaneRow.Height = new GridLength(0);
-			topPane.Visibility = Visibility.Collapsed;
-
-			IPane pane = topPane.Content as IPane;
-			topPane.Content = null;
-			if (pane != null)
-				pane.Closed();
-		}
-
-		public void ShowInBottomPane(string title, object content)
-		{
-			bottomPaneRow.MinHeight = 100;
-			if (sessionSettings.BottomPaneSplitterPosition > 0 && sessionSettings.BottomPaneSplitterPosition < 1) {
-				//Ensure all 3 blocks are in fair conditions
-				NormalizePaneRowHeightValues(topPaneRow, textViewRow);
-
-				textViewRow.Height = new GridLength(1 - sessionSettings.BottomPaneSplitterPosition, GridUnitType.Star);
-				bottomPaneRow.Height = new GridLength(sessionSettings.BottomPaneSplitterPosition, GridUnitType.Star);
-			}
-			bottomPane.Title = title;
-			if (bottomPane.Content != content) {
-				IPane pane = bottomPane.Content as IPane;
-				if (pane != null)
-					pane.Closed();
-				bottomPane.Content = content;
+			if (panePosition == PanePosition.Document) {
+				var layoutDocument = new LayoutDocument() { Title = title, Content = content, ToolTip = toolTip, CanClose = true };
+				var documentPane = this.DockManager.Layout.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
+				documentPane.Children.Add(layoutDocument);
+			} else {
+				var layoutAnchorable = new LayoutAnchorable() { Title = title, Content = content, ToolTip = toolTip, CanClose = true, CanHide = true };
+				var documentPane = this.DockManager.Layout.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
+				Docking.DockingHelper.DockHorizontal(layoutAnchorable, documentPane, new GridLength(200), panePosition == PanePosition.Top);
 			}
-			bottomPane.Visibility = Visibility.Visible;
 		}
 
-		void BottomPane_CloseButtonClicked(object sender, EventArgs e)
-		{
-			sessionSettings.BottomPaneSplitterPosition = bottomPaneRow.Height.Value / (bottomPaneRow.Height.Value + textViewRow.Height.Value);
-			bottomPaneRow.MinHeight = 0;
-			bottomPaneRow.Height = new GridLength(0);
-			bottomPane.Visibility = Visibility.Collapsed;
-
-			IPane pane = bottomPane.Content as IPane;
-			bottomPane.Content = null;
-			if (pane != null)
-				pane.Closed();
-		}
 		#endregion
 
 		public void UnselectAll()

ILSpy/Properties/Resources.Designer.cs

@@ -1008,6 +1008,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Decompile to new tab.
+        /// </summary>
+        public static string DecompileToNewPanel {
+            get {
+                return ResourceManager.GetString("DecompileToNewPanel", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Decompiling....
         /// </summary>

ILSpy/Properties/Resources.resx

@@ -766,4 +766,7 @@ Are you sure you want to continue?</value>
   <data name="Assembly" xml:space="preserve">
     <value>Assembly</value>
   </data>
+  <data name="DecompileToNewPanel" xml:space="preserve">
+    <value>Decompile to new tab</value>
+  </data>
 </root>

ILSpy/Search/AbstractEntitySearchStrategy.cs

@@ -0,0 +1,122 @@
+using System;
+using System.Collections.Concurrent;
+using System.Text.RegularExpressions;
+using System.Threading;
+using System.Windows.Media;
+using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.ILSpy.TreeNodes;
+
+namespace ICSharpCode.ILSpy.Search
+{
+	abstract class AbstractEntitySearchStrategy	: AbstractSearchStrategy
+	{
+		protected readonly Language language;
+		protected readonly ApiVisibility apiVisibility;
+
+		protected AbstractEntitySearchStrategy(Language language, ApiVisibility apiVisibility, IProducerConsumerCollection<SearchResult> resultQueue, params string[] terms)
+			: base(resultQueue, terms)
+		{
+			this.language = language;
+			this.apiVisibility = apiVisibility;
+		}
+
+		protected bool CheckVisibility(IEntity entity)
+		{
+			if (apiVisibility == ApiVisibility.All)
+				return true;
+
+			do {
+				if (apiVisibility == ApiVisibility.PublicOnly) {
+					if (!(entity.Accessibility == Accessibility.Public ||
+						entity.Accessibility == Accessibility.Protected ||
+						entity.Accessibility == Accessibility.ProtectedOrInternal))
+						return false;
+				} else if (apiVisibility == ApiVisibility.PublicAndInternal) {
+					if (!language.ShowMember(entity))
+						return false;
+				}
+				entity = entity.DeclaringTypeDefinition;
+			}
+			while (entity != null);
+
+			return true;
+		}
+
+		protected void OnFoundResult(IEntity entity)
+		{
+			var result = ResultFromEntity(entity);
+			OnFoundResult(result);
+		}
+
+		SearchResult ResultFromEntity(IEntity item)
+		{
+			var declaringType = item.DeclaringTypeDefinition;
+			return new MemberSearchResult {
+				Member = item,
+				Fitness = CalculateFitness(item),
+				Name = GetLanguageSpecificName(item),
+				Location = declaringType != null ? language.TypeToString(declaringType, includeNamespace: true) : item.Namespace,
+				Assembly = item.ParentModule.FullAssemblyName,
+				ToolTip = item.ParentModule.PEFile?.FileName
+			};
+		}
+
+		float CalculateFitness(IEntity member)
+		{
+			string text = member.Name;
+
+			// Probably compiler generated types without meaningful names, show them last
+			if (text.StartsWith("<")) {
+				return 0;
+			}
+
+			// Constructors always have the same name in IL:
+			// Use type name instead
+			if (text == ".cctor" || text == ".ctor") {
+				text = member.DeclaringType.Name;
+			}
+
+			// Ignore generic arguments, it not possible to search based on them either
+			text = ReflectionHelper.SplitTypeParameterCountFromReflectionName(text);
+
+			return 1.0f / text.Length;
+		}
+
+		string GetLanguageSpecificName(IEntity member)
+		{
+			switch (member) {
+				case ITypeDefinition t:
+					return language.TypeToString(t, false);
+				case IField f:
+					return language.FieldToString(f, true, false, false);
+				case IProperty p:
+					return language.PropertyToString(p, true, false, false);
+				case IMethod m:
+					return language.MethodToString(m, true, false, false);
+				case IEvent e:
+					return language.EventToString(e, true, false, false);
+				default:
+					throw new NotSupportedException(member?.GetType() + " not supported!");
+			}
+		}
+
+		static internal ImageSource GetIcon(IEntity member)
+		{
+			switch (member) {
+				case ITypeDefinition t:
+					return TypeTreeNode.GetIcon(t);
+				case IField f:
+					return FieldTreeNode.GetIcon(f);
+				case IProperty p:
+					return PropertyTreeNode.GetIcon(p);
+				case IMethod m:
+					return MethodTreeNode.GetIcon(m);
+				case IEvent e:
+					return EventTreeNode.GetIcon(e);
+				default:
+					throw new NotSupportedException(member?.GetType() + " not supported!");
+			}
+		}
+	}
+}

ILSpy/Search/AbstractSearchStrategy.cs

@@ -15,14 +15,10 @@ namespace ICSharpCode.ILSpy.Search
 		protected readonly Regex regex;
 		protected readonly bool fullNameSearch;
 		protected readonly bool omitGenerics;
-		protected readonly Language language;
-		protected readonly ApiVisibility apiVisibility;
 		private readonly IProducerConsumerCollection<SearchResult> resultQueue;
 
-		protected AbstractSearchStrategy(Language language, ApiVisibility apiVisibility, IProducerConsumerCollection<SearchResult> resultQueue, params string[] terms)
+		protected AbstractSearchStrategy(IProducerConsumerCollection<SearchResult> resultQueue, params string[] terms)
 		{
-			this.language = language;
-			this.apiVisibility = apiVisibility;
 			this.resultQueue = resultQueue;
 
 			if (terms.Length == 1 && terms[0].Length > 2) {
@@ -44,17 +40,17 @@ namespace ICSharpCode.ILSpy.Search
 
 		public abstract void Search(PEFile module, CancellationToken cancellationToken);
 
-		protected virtual bool IsMatch(string entityName)
+		protected virtual bool IsMatch(string name)
 		{
 			if (regex != null) {
-				return regex.IsMatch(entityName);
+				return regex.IsMatch(name);
 			}
 
 			for (int i = 0; i < searchTerm.Length; ++i) {
 				// How to handle overlapping matches?
 				var term = searchTerm[i];
 				if (string.IsNullOrEmpty(term)) continue;
-				string text = entityName;
+				string text = name;
 				switch (term[0]) {
 					case '+': // must contain
 						term = term.Substring(1);
@@ -87,28 +83,6 @@ namespace ICSharpCode.ILSpy.Search
 			return true;
 		}
 
-		protected bool CheckVisibility(IEntity entity)
-		{
-			if (apiVisibility == ApiVisibility.All)
-				return true;
-
-			do {
-				if (apiVisibility == ApiVisibility.PublicOnly) {
-					if (!(entity.Accessibility == Accessibility.Public ||
-						entity.Accessibility == Accessibility.Protected ||
-						entity.Accessibility == Accessibility.ProtectedOrInternal))
-						return false;
-				} else if (apiVisibility == ApiVisibility.PublicAndInternal) {
-					if (!language.ShowMember(entity))
-						return false;
-				}
-				entity = entity.DeclaringTypeDefinition;
-			}
-			while (entity != null);
-
-			return true;
-		}
-
 		bool IsNoncontiguousMatch(string text, string searchTerm)
 		{
 			if (string.IsNullOrEmpty(text) || string.IsNullOrEmpty(searchTerm)) {
@@ -136,9 +110,8 @@ namespace ICSharpCode.ILSpy.Search
 			return false;
 		}
 
-		protected void OnFoundResult(IEntity entity)
+		protected void OnFoundResult(SearchResult result)
 		{
-			var result = ResultFromEntity(entity);
 			resultQueue.TryAdd(result);
 		}
 
@@ -150,75 +123,5 @@ namespace ICSharpCode.ILSpy.Search
 				return null;
 			}
 		}
-
-		SearchResult ResultFromEntity(IEntity item)
-		{
-			var declaringType = item.DeclaringTypeDefinition;
-			return new SearchResult {
-				Member = item,
-				Fitness = CalculateFitness(item),
-				Name = GetLanguageSpecificName(item),
-				Location = declaringType != null ? language.TypeToString(declaringType, includeNamespace: true) : item.Namespace,
-				Assembly = item.ParentModule.FullAssemblyName,
-				ToolTip = item.ParentModule.PEFile?.FileName
-			};
-		}
-
-		float CalculateFitness(IEntity member)
-		{
-			string text = member.Name;
-
-			// Probably compiler generated types without meaningful names, show them last
-			if (text.StartsWith("<")) {
-				return 0;
-			}
-
-			// Constructors always have the same name in IL:
-			// Use type name instead
-			if (text == ".cctor" || text == ".ctor") {
-				text = member.DeclaringType.Name;
-			}
-
-			// Ignore generic arguments, it not possible to search based on them either
-			text = ReflectionHelper.SplitTypeParameterCountFromReflectionName(text);
-
-			return 1.0f / text.Length;
-		}
-
-		string GetLanguageSpecificName(IEntity member)
-		{
-			switch (member) {
-				case ITypeDefinition t:
-					return language.TypeToString(t, false);
-				case IField f:
-					return language.FieldToString(f, true, false, false);
-				case IProperty p:
-					return language.PropertyToString(p, true, false, false);
-				case IMethod m:
-					return language.MethodToString(m, true, false, false);
-				case IEvent e:
-					return language.EventToString(e, true, false, false);
-				default:
-					throw new NotSupportedException(member?.GetType() + " not supported!");
-			}
-		}
-
-		internal static ImageSource GetIcon(IEntity member)
-		{
-			switch (member) {
-				case ITypeDefinition t:
-					return TypeTreeNode.GetIcon(t);
-				case IField f:
-					return FieldTreeNode.GetIcon(f);
-				case IProperty p:
-					return PropertyTreeNode.GetIcon(p);
-				case IMethod m:
-					return MethodTreeNode.GetIcon(m);
-				case IEvent e:
-					return EventTreeNode.GetIcon(e);
-				default:
-					throw new NotSupportedException(member?.GetType() + " not supported!");
-			}
-		}
 	}
 }

ILSpy/Search/AssemblySearchStrategy.cs

@@ -0,0 +1,111 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using System.Reflection.Metadata;
+using System.Threading;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.Decompiler.Util;
+using ICSharpCode.ILSpy.TreeNodes;
+using ICSharpCode.TreeView;
+
+namespace ICSharpCode.ILSpy.Search
+{
+	class AssemblySearchStrategy : AbstractSearchStrategy
+	{
+		readonly AssemblySearchKind searchKind;
+
+		public AssemblySearchStrategy(string term, IProducerConsumerCollection<SearchResult> resultQueue, AssemblySearchKind searchKind)
+			: this(resultQueue, new[] { term }, searchKind)
+		{
+		}
+
+		public AssemblySearchStrategy(IProducerConsumerCollection<SearchResult> resultQueue, string[] terms, AssemblySearchKind searchKind)
+			: base(resultQueue, terms)
+		{
+			this.searchKind = searchKind;
+		}
+
+		public override void Search(PEFile module, CancellationToken cancellationToken)
+		{
+			cancellationToken.ThrowIfCancellationRequested();
+
+			if (searchKind == AssemblySearchKind.NameOrFileName) {
+				string localName = GetNameToMatch(module, AssemblySearchKind.Name);
+				string fileName = Path.GetFileName(GetNameToMatch(module, AssemblySearchKind.FilePath));
+				if (IsMatch(localName) || IsMatch(fileName))
+					OnFoundResult(module);
+				return;
+			}
+
+			string name = GetNameToMatch(module, searchKind);
+			if (IsMatch(name))
+				OnFoundResult(module);
+		}
+
+		string GetNameToMatch(PEFile module, AssemblySearchKind kind)
+		{
+			switch (kind) {
+				case AssemblySearchKind.FullName:
+					return module.FullName;
+				case AssemblySearchKind.Name:
+					return module.Name;
+				case AssemblySearchKind.FilePath:
+					return module.FileName;
+			}
+
+			if (!module.IsAssembly)
+				return null;
+
+			var metadata = module.Metadata;
+			var definition = module.Metadata.GetAssemblyDefinition();
+
+			switch (kind) {
+				case AssemblySearchKind.Culture:
+					if (definition.Culture.IsNil)
+						return "neutral";
+					return metadata.GetString(definition.Culture);
+				case AssemblySearchKind.Version:
+					return definition.Version.ToString();
+				case AssemblySearchKind.PublicKey:
+					return module.Metadata.GetPublicKeyToken();
+				case AssemblySearchKind.HashAlgorithm:
+					return definition.HashAlgorithm.ToString();
+				case AssemblySearchKind.Flags:
+					return definition.Flags.ToString();
+			}
+
+			return null;
+		}
+
+		void OnFoundResult(PEFile module)
+		{
+			var result = new AssemblySearchResult {
+				Module = module,
+				Fitness = 1.0f / module.Name.Length,
+				Name = module.Name,
+				Location = module.FileName,
+				Assembly = module.FullName,
+				ToolTip = module.FileName,
+			};
+			OnFoundResult(result);
+		}
+	}
+
+	enum AssemblySearchKind
+	{
+		NameOrFileName,
+		Name,
+		FullName,
+		FilePath,
+		Culture,
+		Version,
+		PublicKey,
+		HashAlgorithm,
+		Flags
+	}
+}

ILSpy/Search/LiteralSearchStrategy.cs

@@ -15,7 +15,7 @@ using System.Collections.Concurrent;
 
 namespace ICSharpCode.ILSpy.Search
 {
-	class LiteralSearchStrategy : AbstractSearchStrategy
+	class LiteralSearchStrategy : AbstractEntitySearchStrategy
 	{
 		readonly TypeCode searchTermLiteralType;
 		readonly object searchTermLiteralValue;

ILSpy/Search/MemberSearchStrategy.cs

@@ -6,7 +6,7 @@ using ICSharpCode.Decompiler.TypeSystem;
 
 namespace ICSharpCode.ILSpy.Search
 {
-	class MemberSearchStrategy : AbstractSearchStrategy
+	class MemberSearchStrategy : AbstractEntitySearchStrategy
 	{
 		readonly MemberSearchKind searchKind;
 

ILSpy/Search/MetadataTokenSearchStrategy.cs

@@ -9,7 +9,7 @@ using ICSharpCode.Decompiler.TypeSystem;
 
 namespace ICSharpCode.ILSpy.Search
 {
-	class MetadataTokenSearchStrategy : AbstractSearchStrategy
+	class MetadataTokenSearchStrategy : AbstractEntitySearchStrategy
 	{
 		readonly EntityHandle searchTermToken;