Extend UseLambdaSyntax to emit statement lambdas

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

@@ -105,6 +105,7 @@
     <None Include="TestCases\ILPretty\ExtensionEncodingV2.il" />
     <None Include="testcases\ilpretty\ExtensionEncodingV1.il" />
     <None Include="TestCases\ILPretty\GuessAccessors.il" />
+    <None Include="TestCases\ILPretty\InaccessibleParameterTypes.il" />
     <None Include="TestCases\ILPretty\Issue2260SwitchString.il" />
     <None Include="TestCases\ILPretty\Issue3442.il" />
     <None Include="TestCases\ILPretty\Issue3344CkFinite.il" />
@@ -209,6 +210,8 @@
     <None Include="TestCases\ILPretty\FSharpUsing_Release.cs" />
     <Compile Remove="TestCases\ILPretty\GuessAccessors.cs" />
     <None Include="TestCases\ILPretty\GuessAccessors.cs" />
+    <Compile Remove="TestCases\ILPretty\InaccessibleParameterTypes.cs" />
+    <None Include="TestCases\ILPretty\InaccessibleParameterTypes.cs" />
     <Compile Remove="TestCases\ILPretty\NoAccessorProperties.cs" />
     <None Include="TestCases\ILPretty\NoAccessorProperties.cs" />
     <Compile Remove="TestCases\ILPretty\Issue1145.cs" />

ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs

@@ -51,6 +51,12 @@ public void AllFilesHaveTests()
 			}
 		}
 
+		[Test]
+		public async Task AnonymousMethodEdgeCases()
+		{
+			await Run();
+		}
+
 		[Test, Ignore("Need to decide how to represent virtual methods without 'newslot' flag")]
 		public async Task Issue379()
 		{
@@ -353,6 +359,12 @@ public async Task GuessAccessors()
 			await Run();
 		}
 
+		[Test]
+		public async Task InaccessibleParameterTypes()
+		{
+			await Run();
+		}
+
 		[Test]
 		public async Task EmptyBodies()
 		{

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

@@ -0,0 +1,22 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+	public class AnonymousMethodEdgeCases
+	{
+		public Func<int, int> AssignmentIsTheLambdaBody()
+		{
+			return (int x) => {
+				int num;
+				return num = x;
+			};
+		}
+
+		public Action<object> UsedParameterWithInvalidName()
+		{
+			return (object value) => {
+				Console.WriteLine(value);
+			};
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/AnonymousMethodEdgeCases.il

@@ -0,0 +1,79 @@
+// Hand-written input for two anonymous-method shapes that C# cannot express directly:
+// an expression-bodied lambda whose body is the assignment declaring its own local, and
+// a parameter whose metadata name is not a valid C# identifier but IS used in the body.
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )
+  .ver 4:0:0:0
+}
+.assembly extern System.Core
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )
+  .ver 4:0:0:0
+}
+.assembly AnonymousMethodEdgeCases
+{
+  .ver 1:0:0:0
+}
+.module AnonymousMethodEdgeCases.dll
+.imagebase 0x00400000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003
+.corflags 0x00000001
+
+.class public auto ansi beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.ILPretty.AnonymousMethodEdgeCases
+	extends [mscorlib]System.Object
+{
+	.method public hidebysig specialname rtspecialname instance void .ctor () cil managed
+	{
+		.maxstack 8
+		ldarg.0
+		call instance void [mscorlib]System.Object::.ctor()
+		ret
+	}
+
+	.method public hidebysig instance class [System.Core]System.Func`2<int32, int32> AssignmentIsTheLambdaBody () cil managed
+	{
+		.maxstack 8
+		ldarg.0
+		ldftn instance int32 ICSharpCode.Decompiler.Tests.TestCases.ILPretty.AnonymousMethodEdgeCases::'<AssignmentIsTheLambdaBody>b__1_0'(int32)
+		newobj instance void class [System.Core]System.Func`2<int32, int32>::.ctor(object, native int)
+		ret
+	}
+
+	// return num = x; -- the store's value is the return value, so the local has a store and
+	// no load, and the decompiled lambda body is the assignment itself.
+	.method private hidebysig instance int32 '<AssignmentIsTheLambdaBody>b__1_0' (int32 x) cil managed
+	{
+		.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+		.maxstack 2
+		.locals init (
+			[0] int32 num
+		)
+		ldarg.1
+		dup
+		stloc.0
+		ret
+	}
+
+	.method public hidebysig instance class [System.Core]System.Action`1<object> UsedParameterWithInvalidName () cil managed
+	{
+		.maxstack 8
+		ldarg.0
+		ldftn instance void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.AnonymousMethodEdgeCases::'<UsedParameterWithInvalidName>b__2_0'(object)
+		newobj instance void class [System.Core]System.Action`1<object>::.ctor(object, native int)
+		ret
+	}
+
+	// The parameter name '<p0>' is what C# emits for an anonymous method declared without a
+	// parameter list; used here, so the lambda's parameter list has to name it somehow.
+	.method private hidebysig instance void '<UsedParameterWithInvalidName>b__2_0' (object '<p0>') cil managed
+	{
+		.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+		.maxstack 8
+		ldarg.1
+		call void [mscorlib]System.Console::WriteLine(object)
+		ret
+	}
+}

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

@@ -0,0 +1,31 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+	public class InaccessibleParameterTypes
+	{
+		private class Hidden
+		{
+		}
+
+		public delegate void Handler(Hidden h);
+
+		public static void Register(Action<Hidden> callback)
+		{
+		}
+	}
+	public class InaccessibleParameterTypesConsumer
+	{
+		public InaccessibleParameterTypes.Handler Create()
+		{
+			return delegate {
+			};
+		}
+
+		public void Run()
+		{
+			InaccessibleParameterTypes.Register(delegate {
+			});
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/InaccessibleParameterTypes.il

@@ -0,0 +1,138 @@
+// Anonymous methods whose delegate signature contains a type the use site cannot name.
+// IL (unlike C#) permits a public delegate with a less-accessible parameter type, so the
+// parameter-list-less "delegate {}" form is the only C# syntax the consumer class below
+// could legally have used - the decompiler must not expand it to a lambda parameter list.
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly extern System.Core
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly InaccessibleParameterTypes
+{
+  .ver 1:0:0:0
+}
+.module InaccessibleParameterTypes.dll
+.imagebase 0x00400000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00020003    //  ILONLY 32BITPREFERRED
+
+.class public auto ansi beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes
+	extends [mscorlib]System.Object
+{
+	.class nested private auto ansi beforefieldinit Hidden
+		extends [mscorlib]System.Object
+	{
+		.method public hidebysig specialname rtspecialname instance void .ctor () cil managed
+		{
+			.maxstack 8
+
+			ldarg.0
+			call instance void [mscorlib]System.Object::.ctor()
+			ret
+		}
+	}
+
+	.class nested public auto ansi sealed Handler
+		extends [mscorlib]System.MulticastDelegate
+	{
+		.method public hidebysig specialname rtspecialname instance void .ctor (object 'object', native int 'method') runtime managed
+		{
+		}
+
+		.method public hidebysig newslot virtual instance void Invoke (class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden h) runtime managed
+		{
+		}
+	}
+
+	.method public hidebysig static void Register (class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden> callback) cil managed
+	{
+		.maxstack 8
+
+		ret
+	}
+
+	.method public hidebysig specialname rtspecialname instance void .ctor () cil managed
+	{
+		.maxstack 8
+
+		ldarg.0
+		call instance void [mscorlib]System.Object::.ctor()
+		ret
+	}
+}
+
+.class public auto ansi beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer
+	extends [mscorlib]System.Object
+{
+	// Fields
+	.field private static class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Handler '<>f__am$cache0'
+	.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+	.field private static class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden> '<>f__am$cache1'
+	.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+
+	// Methods
+	.method public hidebysig instance class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Handler Create () cil managed
+	{
+		.maxstack 8
+
+		ldsfld class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Handler ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<>f__am$cache0'
+		brtrue.s IL_0016
+
+		ldnull
+		ldftn void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<Create>m__0'(class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden)
+		newobj instance void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Handler::.ctor(object, native int)
+		stsfld class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Handler ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<>f__am$cache0'
+
+		IL_0016: ldsfld class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Handler ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<>f__am$cache0'
+		ret
+	}
+
+	.method public hidebysig instance void Run () cil managed
+	{
+		.maxstack 8
+
+		ldsfld class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden> ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<>f__am$cache1'
+		brtrue.s IL_0016
+
+		ldnull
+		ldftn void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<Run>m__1'(class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden)
+		newobj instance void class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden>::.ctor(object, native int)
+		stsfld class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden> ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<>f__am$cache1'
+
+		IL_0016: ldsfld class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden> ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypesConsumer::'<>f__am$cache1'
+		call void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes::Register(class [System.Core]System.Action`1<class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden>)
+		ret
+	}
+
+	.method private hidebysig static void '<Create>m__0' (class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden '') cil managed
+	{
+		.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+		.maxstack 8
+
+		ret
+	}
+
+	.method private hidebysig static void '<Run>m__1' (class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.InaccessibleParameterTypes/Hidden '') cil managed
+	{
+		.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+		.maxstack 8
+
+		ret
+	}
+
+	.method public hidebysig specialname rtspecialname instance void .ctor () cil managed
+	{
+		.maxstack 8
+
+		ldarg.0
+		call instance void [mscorlib]System.Object::.ctor()
+		ret
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue1038.cs

@@ -4,7 +4,7 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
 {
 	public class Issue1038<TK, TR> where TR : class, new()
 	{
-		public event Action<TK, TR> TestEvent = delegate {
+		public event Action<TK, TR> TestEvent = (TK A_0, TR A_1) => {
 		};
 	}
 }

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

@@ -524,7 +524,7 @@ public static Func<Task<int>> AsyncLambda()
 
 		public static Func<Task<int>> AsyncDelegate()
 		{
-			return async delegate {
+			return async () => {
 				await Task.Delay(10);
 				return 2;
 			};

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

@@ -119,7 +119,7 @@ public static Func<ValueTask<int>> AsyncLambda()
 
 		public static Func<ValueTask<int>> AsyncDelegate()
 		{
-			return async delegate {
+			return async () => {
 				await Task.Delay(10);
 				return 2;
 			};

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

@@ -990,7 +990,7 @@ public async Task<int> DeconstructionAssignmentToCapturedLocals(string file)
 		{
 			int a = 0;
 			int b = 0;
-			await Task.Run(delegate {
+			await Task.Run(() => {
 				(a, b) = GetTuple<int, int>();
 			});
 			return a + b;