Add some tests for native integers.

The conversion roundtrip tests are disabled due to https://github.com/dotnet/roslyn/issues/45929

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="3.7.0-2.final" />
-    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.7.0-2.final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.7.0-3.final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.7.0-3.final" />
     <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" />

ICSharpCode.Decompiler.Tests/RoundtripAssembly.cs

@@ -88,39 +88,65 @@ namespace ICSharpCode.Decompiler.Tests
 		[Test]
 		public void ExplicitConversions()
 		{
-			RunWithOutput("Random Tests\\TestCases", "ExplicitConversions.exe");
+			RunWithOutput("Random Tests\\TestCases", "ExplicitConversions.exe", LanguageVersion.CSharp8_0);
 		}
 
 		[Test]
 		public void ExplicitConversions_32()
 		{
-			RunWithOutput("Random Tests\\TestCases", "ExplicitConversions_32.exe");
+			RunWithOutput("Random Tests\\TestCases", "ExplicitConversions_32.exe", LanguageVersion.CSharp8_0);
+		}
+
+		[Test]
+		[Ignore("Waiting for https://github.com/dotnet/roslyn/issues/45929")]
+		public void ExplicitConversions_With_NativeInts()
+		{
+			RunWithOutput("Random Tests\\TestCases", "ExplicitConversions.exe", LanguageVersion.Preview);
+		}
+
+		[Test]
+		[Ignore("Waiting for https://github.com/dotnet/roslyn/issues/45929")]
+		public void ExplicitConversions_32_With_NativeInts()
+		{
+			RunWithOutput("Random Tests\\TestCases", "ExplicitConversions_32.exe", LanguageVersion.Preview);
 		}
 
 		[Test]
 		public void Random_TestCase_1()
 		{
-			RunWithOutput("Random Tests\\TestCases", "TestCase-1.exe");
+			RunWithOutput("Random Tests\\TestCases", "TestCase-1.exe", LanguageVersion.CSharp8_0);
+		}
+
+		[Test]
+		[Ignore("Waiting for https://github.com/dotnet/roslyn/issues/45929")]
+		public void Random_TestCase_1_With_NativeInts()
+		{
+			RunWithOutput("Random Tests\\TestCases", "TestCase-1.exe", LanguageVersion.Preview);
 		}
 
-		void RunWithTest(string dir, string fileToRoundtrip, string fileToTest, string keyFile = null, bool useOldProjectFormat = false)
+		// Let's limit the roundtrip tests to C# 8.0 for now; because 9.0 is still in preview
+		// and the generated project doesn't build as-is.
+		const LanguageVersion defaultLanguageVersion = LanguageVersion.CSharp8_0;
+
+		void RunWithTest(string dir, string fileToRoundtrip, string fileToTest, LanguageVersion languageVersion = defaultLanguageVersion, string keyFile = null, bool useOldProjectFormat = false)
 		{
-			RunInternal(dir, fileToRoundtrip, outputDir => RunTest(outputDir, fileToTest), keyFile, useOldProjectFormat);
+			RunInternal(dir, fileToRoundtrip, outputDir => RunTest(outputDir, fileToTest), languageVersion, snkFilePath: keyFile, useOldProjectFormat: useOldProjectFormat);
 		}
 
-		void RunWithOutput(string dir, string fileToRoundtrip)
+		void RunWithOutput(string dir, string fileToRoundtrip, LanguageVersion languageVersion = defaultLanguageVersion)
 		{
 			string inputDir = Path.Combine(TestDir, dir);
 			RunInternal(dir, fileToRoundtrip,
-				outputDir => Tester.RunAndCompareOutput(fileToRoundtrip, Path.Combine(inputDir, fileToRoundtrip), Path.Combine(outputDir, fileToRoundtrip)));
+				outputDir => Tester.RunAndCompareOutput(fileToRoundtrip, Path.Combine(inputDir, fileToRoundtrip), Path.Combine(outputDir, fileToRoundtrip)),
+				languageVersion);
 		}
 
-		void RunOnly(string dir, string fileToRoundtrip)
+		void RunOnly(string dir, string fileToRoundtrip, LanguageVersion languageVersion = defaultLanguageVersion)
 		{
-			RunInternal(dir, fileToRoundtrip, outputDir => { });
+			RunInternal(dir, fileToRoundtrip, outputDir => { }, languageVersion);
 		}
 
-		void RunInternal(string dir, string fileToRoundtrip, Action<string> testAction, string snkFilePath = null, bool useOldProjectFormat = false)
+		void RunInternal(string dir, string fileToRoundtrip, Action<string> testAction, LanguageVersion languageVersion, string snkFilePath = null, bool useOldProjectFormat = false)
 		{
 			if (!Directory.Exists(TestDir)) {
 				Assert.Ignore($"Assembly-roundtrip test ignored: test directory '{TestDir}' needs to be checked out separately." + Environment.NewLine +
@@ -131,8 +157,8 @@ namespace ICSharpCode.Decompiler.Tests
 			string outputDir = inputDir + "-output";
 			if (inputDir.EndsWith("TestCases")) {
 				// make sure output dir names are unique so that we don't get trouble due to parallel test execution
-				decompiledDir += Path.GetFileNameWithoutExtension(fileToRoundtrip);
-				outputDir += Path.GetFileNameWithoutExtension(fileToRoundtrip);
+				decompiledDir += Path.GetFileNameWithoutExtension(fileToRoundtrip) + "_" + languageVersion.ToString();
+				outputDir += Path.GetFileNameWithoutExtension(fileToRoundtrip) + "_" + languageVersion.ToString();
 			}
 			ClearDirectory(decompiledDir);
 			ClearDirectory(outputDir);
@@ -155,9 +181,7 @@ namespace ICSharpCode.Decompiler.Tests
 						// use a fixed GUID so that we can diff the output between different ILSpy runs without spurious changes
 						var projectGuid = Guid.Parse("{127C83E4-4587-4CF9-ADCA-799875F3DFE6}");
 
-						// Let's limit the roundtrip tests to C# 7.3 for now; because 8.0 is still in preview
-						// and the generated project doesn't build as-is.
-						var settings = new DecompilerSettings(LanguageVersion.CSharp7_3);
+						var settings = new DecompilerSettings(languageVersion);
 						if (useOldProjectFormat) {
 							settings.UseSdkStyleProjectFormat = false;
 						}

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

@@ -0,0 +1,77 @@
+// Copyright (c) 2020 Daniel Grunwald
+// 
+// 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;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
+{
+	internal class NativeInts
+	{
+		private const nint nint_const = 42;
+		private const nuint nuint_const = 99u;
+
+		private IntPtr intptr;
+		private UIntPtr uintptr;
+		private nint i;
+		private nuint u;
+		private int i32;
+		private uint u32;
+		private long i64;
+		private ulong u64;
+		private (IntPtr, nint, UIntPtr, nuint) tuple_field;
+		private Dictionary<nint, IntPtr> dict1;
+		private Dictionary<IntPtr, nint> dict2;
+
+		public void Convert()
+		{
+			intptr = i;
+			intptr = (nint)u;
+			intptr = (nint)(nuint)uintptr;
+
+			uintptr = (nuint)i;
+			uintptr = u;
+			uintptr = (nuint)(nint)intptr;
+
+			i = intptr;
+			i = (nint)u;
+			i = (nint)(nuint)uintptr;
+
+			u = (nuint)i;
+			u = uintptr;
+			u = (nuint)(nint)intptr;
+		}
+
+		public void Convert2()
+		{
+			i32 = (int)i;
+			i = i32;
+			intptr = (IntPtr)i32;
+
+			i64 = (long)intptr;
+			i64 = i;
+			i = (nint)i64;
+
+			u32 = (uint)i;
+			i = (nint)u32;
+
+			u64 = (uint)i;
+			i = (nint)u64;
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/CSharpLanguageVersion.cs

@@ -17,7 +17,7 @@ namespace ICSharpCode.Decompiler.CSharp
 		CSharp7_2 = 702,
 		CSharp7_3 = 703,
 		CSharp8_0 = 800,
-		CSharp9_0 = 900,
+		Preview = 900,
 		Latest = 0x7FFFFFFF
 	}
 }

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -1650,8 +1650,15 @@ namespace ICSharpCode.Decompiler.CSharp
 			IType GetType(KnownTypeCode typeCode)
 			{
 				IType type = compilation.FindType(typeCode);
-				if (inst.IsLifted)
+				// Prefer n(u)int over (U)IntPtr
+				if (typeCode == KnownTypeCode.IntPtr && settings.NativeIntegers && !type.Equals(context.TypeHint)) {
+					type = SpecialType.NInt;
+				} else if (typeCode == KnownTypeCode.UIntPtr && settings.NativeIntegers && !type.Equals(context.TypeHint)) {
+					type = SpecialType.NUInt;
+				}
+				if (inst.IsLifted) {
 					type = NullableType.Create(compilation, type);
+				}
 				return type;
 			}
 

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -114,7 +114,7 @@ namespace ICSharpCode.Decompiler
 				staticLocalFunctions = false;
 				ranges = false;
 			}
-			if (languageVersion < CSharp.LanguageVersion.CSharp9_0) {
+			if (languageVersion < CSharp.LanguageVersion.Preview) {
 				nativeIntegers = false;
 			}
 		}
@@ -122,7 +122,7 @@ namespace ICSharpCode.Decompiler
 		public CSharp.LanguageVersion GetMinimumRequiredVersion()
 		{
 			if (nativeIntegers)
-				return CSharp.LanguageVersion.CSharp9_0;
+				return CSharp.LanguageVersion.Preview;
 			if (nullableReferenceTypes || readOnlyMethods || asyncEnumerator || asyncUsingAndForEachStatement || staticLocalFunctions || ranges)
 				return CSharp.LanguageVersion.CSharp8_0;
 			if (introduceUnmanagedConstraint || tupleComparisons || stackAllocInitializers || patternBasedFixedStatement)

ILSpy.Tests/ILSpy.Tests.csproj

@@ -46,8 +46,8 @@
 
   <ItemGroup>
     <PackageReference Include="DiffLib" Version="2017.7.26.1241" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.7.0-2.final" />
-    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.7.0-2.final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.7.0-3.final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.7.0-3.final" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.13.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.7.1" />
     <PackageReference Include="NUnit" Version="3.11.0" />

ILSpy/Languages/CSharpLanguage.cs

@@ -107,7 +107,7 @@ namespace ICSharpCode.ILSpy
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp7_2.ToString(), "C# 7.2 / VS 2017.4"),
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp7_3.ToString(), "C# 7.3 / VS 2017.7"),
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp8_0.ToString(), "C# 8.0 / VS 2019"),
-						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp9_0.ToString(), "C# 9.0 (experimental)"),
+						new LanguageVersion(Decompiler.CSharp.LanguageVersion.Preview.ToString(), "C# 9.0 (experimental)"),
 					};
 				}
 				return versions;