Fix #3624: decompile semi-auto properties with the C# 14 field keyword

ICSharpCode.Decompiler.Tests/Helpers/Tester.cs

@@ -457,6 +457,7 @@ private static string ReplacePrivImplDetails(string il)
 				"System.Linq.Queryable.dll",
 				"System.IO.FileSystem.Watcher.dll",
 				"System.Memory.dll",
+				"System.ObjectModel.dll",
 				"System.Threading.dll",
 				"System.Threading.Thread.dll",
 				"System.Runtime.dll",

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

@@ -234,6 +234,8 @@
     <None Include="TestCases\ILPretty\Unsafe.cs" />
     <Compile Remove="TestCases\ILPretty\WeirdEnums.cs" />
     <None Include="TestCases\ILPretty\WeirdEnums.cs" />
+    <Compile Remove="TestCases\Pretty\FieldKeyword.cs" />
+    <None Include="TestCases\Pretty\FieldKeyword.cs" />
     <Compile Remove="TestCases\Pretty\IndexRangeTest.cs" />
     <None Include="TestCases\Pretty\IndexRangeTest.cs" />
     <Compile Remove="TestCases\Pretty\MetadataAttributes.cs" />
@@ -248,6 +250,8 @@
     <None Include="TestCases\Ugly\NoDecimalConstants.Expected.cs" />
     <Compile Remove="TestCases\Ugly\NoExtensionMethods.Expected.cs" />
     <None Include="TestCases\Ugly\NoExtensionMethods.Expected.cs" />
+    <Compile Remove="TestCases\Ugly\NoFieldKeyword.Expected.cs" />
+    <None Include="TestCases\Ugly\NoFieldKeyword.Expected.cs" />
     <Compile Remove="TestCases\Ugly\NoForEachStatement.Expected.cs" />
     <None Include="TestCases\Ugly\NoForEachStatement.Expected.cs" />
     <Compile Remove="TestCases\Ugly\NoLocalFunctions.Expected.cs" />

ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs

@@ -687,6 +687,12 @@ public async Task ExtensionEverything([ValueSource(nameof(roslyn5OrNewerOptions)
 			await RunForLibrary(cscOptions: cscOptions | CompilerOptions.Preview | CompilerOptions.NullableEnable);
 		}
 
+		[Test]
+		public async Task FieldKeyword([ValueSource(nameof(roslyn5OrNewerOptions))] CompilerOptions cscOptions)
+		{
+			await RunForLibrary(cscOptions: cscOptions | CompilerOptions.NullableEnable);
+		}
+
 		[Test]
 		public async Task NullPropagation([ValueSource(nameof(roslynOnlyOptions))] CompilerOptions cscOptions)
 		{

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

@@ -0,0 +1,246 @@
+using System;
+using System.ComponentModel;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
+{
+	internal class FieldKeyword
+	{
+		public class BaseVirtual
+		{
+			public virtual int P {
+				get {
+					return field;
+				}
+				set {
+					field = value + 1;
+				}
+			}
+		}
+
+		public class DerivedVirtual : BaseVirtual
+		{
+			public override int P {
+				get {
+					return field * 2;
+				}
+				set {
+					field = value - 1;
+				}
+			}
+		}
+
+		public class Generic<T> where T : class
+		{
+			public T? Item {
+				get {
+					return field;
+				}
+				set {
+					if (value != null)
+					{
+						field = value;
+					}
+				}
+			}
+
+			public T Lazy => field ?? (field = Activator.CreateInstance<T>());
+		}
+
+		public class Notify : INotifyPropertyChanged
+		{
+			public string Name {
+				get {
+					return field;
+				}
+				set {
+					if (field != value)
+					{
+						field = value;
+						PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Name"));
+					}
+				}
+			} = "";
+
+			public event PropertyChangedEventHandler? PropertyChanged;
+		}
+
+		public struct StructProperties
+		{
+			public int Value {
+				get {
+					return field;
+				}
+				set {
+					field = value & 0xFF;
+				}
+			}
+
+			public readonly int Doubled => field * 2;
+
+			public StructProperties(int doubled)
+			{
+				Doubled = doubled;
+			}
+		}
+
+		public class RealFieldName
+		{
+			private int field;
+
+			public int PlusOne => this.field + 1;
+
+			public void Reset()
+			{
+				field = 0;
+			}
+		}
+
+		// 0.00m and -0.0 compare equal to their defaults but are observably different, so
+		// neither initializer may be dropped as a redundant default.
+		public struct PreciseDefaults
+		{
+			public decimal Scale {
+				get {
+					return field;
+				}
+				set {
+					field = value;
+				}
+			} = 0.00m;
+
+			public double Sign {
+				get {
+					return field;
+				}
+				set {
+					field = value;
+				}
+			} = -0.0;
+
+			public PreciseDefaults()
+			{
+			}
+		}
+
+		public Func<int> Capture {
+			get {
+				return () => (field != null) ? 1 : 0;
+			}
+			set;
+		}
+
+		public int GetOnly {
+			get {
+				if (field == 0)
+				{
+					field = 42;
+				}
+				return field;
+			}
+		}
+
+		public string InitChecked {
+			get;
+			init {
+				field = value.Trim();
+			}
+		} = "";
+
+		public int LazyGet {
+			get {
+				if (field == 0)
+				{
+					field = ComputeDefault();
+				}
+				return field;
+			}
+			set;
+		}
+
+		public string NullResilient => field ?? (field = CreateDefault());
+
+		public string? OptionalText {
+			get {
+				return field;
+			}
+			set {
+				field = value ?? string.Empty;
+			}
+		}
+
+		public int SetOnly {
+			set {
+				field = value * 2;
+			}
+		}
+
+		public int SetterValidated {
+			get;
+			set {
+				if (value < 0)
+				{
+					throw new ArgumentOutOfRangeException("value");
+				}
+				field = value;
+			}
+		}
+
+		public static int StaticCounter {
+			get {
+				return field;
+			}
+			set {
+				field = Math.Max(field, value);
+			}
+		}
+
+		public static Func<int> StaticFuncProperty {
+			get {
+				return () => (field == null) ? 1 : 2;
+			}
+			set;
+		}
+
+		public int TrivialGet => field;
+
+		public int ViaLocalFunction {
+			get {
+				return Twice();
+				int Twice()
+				{
+					return field * 2;
+				}
+			}
+			set;
+		}
+
+		[field: NonSerialized]
+		public int WithFieldAttribute {
+			get {
+				return field;
+			}
+			set {
+				field = value & 0xF;
+			}
+		}
+
+		public int WithInit {
+			get {
+				return field;
+			}
+			set {
+				field = value + 1;
+			}
+		} = 5;
+
+		private static int ComputeDefault()
+		{
+			return 7;
+		}
+
+		private static string CreateDefault()
+		{
+			return "x";
+		}
+	}
+}

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

@@ -0,0 +1,60 @@
+using System;
+#if !OPT
+using System.Diagnostics;
+#endif
+using System.Runtime.CompilerServices;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Ugly;
+
+internal class GenericHolder<T> where T : class
+{
+	[CompilerGenerated]
+#if !OPT
+	[DebuggerBrowsable(DebuggerBrowsableState.Never)]
+#endif
+	private T Value__BackingField;
+
+	public T Value {
+		get {
+			return Value__BackingField;
+		}
+		set {
+			if (value != null)
+			{
+				Value__BackingField = value;
+			}
+		}
+	}
+}
+internal class NoFieldKeyword
+{
+	[CompilerGenerated]
+#if !OPT
+	[DebuggerBrowsable(DebuggerBrowsableState.Never)]
+#endif
+	private int Clamped__BackingField;
+
+	[CompilerGenerated]
+#if !OPT
+	[DebuggerBrowsable(DebuggerBrowsableState.Never)]
+#endif
+	private int WithInitializer__BackingField = 5;
+
+	public int Clamped {
+		get {
+			return Clamped__BackingField;
+		}
+		set {
+			Clamped__BackingField = Math.Max(0, value);
+		}
+	}
+
+	public int WithInitializer {
+		get {
+			return WithInitializer__BackingField;
+		}
+		set {
+			WithInitializer__BackingField = value + 1;
+		}
+	}
+}