Merge branch 'master' into pattern-matching

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

@@ -52,6 +52,7 @@
     <PackageReference Include="Microsoft.DiaSymReader.Converter.Xml" Version="$(DSRConverterXmlVersion)" />
     <PackageReference Include="NUnit3TestAdapter" Version="$(NUnitAdapterVersion)" />
     <PackageReference Include="NUnit" Version="$(NUnitVersion)" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="$(MicrosoftNETTestSdkVersion)" />
     <PackageReference Include="System.Memory" Version="4.5.4" />
     <PackageReference Include="Mono.Cecil" Version="$(MonoCecilVersion)" />
     <PackageReference Include="Microsoft.NETCore.ILAsm" Version="$(ILAsmVersion)" />
@@ -108,6 +109,7 @@
     <Compile Include="TestCases\Correctness\DynamicTests.cs" />
     <Compile Include="TestCases\Correctness\StringConcat.cs" />
     <Compile Include="TestCases\Pretty\PatternMatching.cs" />
+    <None Include="TestCases\Pretty\CovariantReturns.cs" />
     <Compile Include="TestCases\VBPretty\VBPropertiesTest.cs" />
     <None Include="TestCases\ILPretty\Issue2260SwitchString.cs" />
     <None Include="TestCases\Pretty\Records.cs" />

ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs

@@ -579,6 +579,12 @@ public void CS9_ExtensionGetEnumerator([ValueSource(nameof(dotnetCoreOnlyOptions
 			RunForLibrary(cscOptions: cscOptions | CompilerOptions.Preview);
 		}
 
+		[Test]
+		public void CovariantReturns([ValueSource(nameof(dotnetCoreOnlyOptions))] CompilerOptions cscOptions)
+		{
+			RunForLibrary(cscOptions: cscOptions | CompilerOptions.Preview);
+		}
+
 		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.Tests/TestCases/Correctness/OverloadResolution.cs

@@ -36,6 +36,7 @@ static void Main()
 			Issue1747();
 			CallAmbiguousOutParam();
 			CallWithInParam();
+			Issue2444.M2();
 		}
 
 		#region ConstructorTest
@@ -334,6 +335,38 @@ static void InVsRegularParam(int i)
 		}
 #endif
 		#endregion
+
+		#region #2444
+		public struct Issue2444
+		{
+			public class X { }
+			public class Y { }
+
+			public static implicit operator Issue2444(X x)
+			{
+				Console.WriteLine("#2444: op_Implicit(X)");
+				return new Issue2444();
+			}
+
+			public static implicit operator Issue2444(Y y)
+			{
+				Console.WriteLine("#2444: op_Implicit(Y)");
+				return new Issue2444();
+			}
+
+			public static void M1(Issue2444 z)
+			{
+				Console.WriteLine(string.Format("#2444: M1({0})", z));
+			}
+
+			public static void M2()
+			{
+				Console.WriteLine("#2444: before M1");
+				M1((X)null);
+				Console.WriteLine("#2444: after M1");
+			}
+		}
+		#endregion
 	}
 
 	class IndexerTests

ICSharpCode.Decompiler.Tests/TestCases/PdbGen/ForLoopTests.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <symbols>
   <files>
-    <file id="1" name="ICSharpCode.Decompiler.Tests.TestCases.PdbGen\ForLoopTests.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
+    <file id="1" name="ICSharpCode\Decompiler\Tests\TestCases\PdbGen\ForLoopTests.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.PdbGen
 {

ICSharpCode.Decompiler.Tests/TestCases/PdbGen/HelloWorld.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <symbols>
   <files>
-    <file id="1" name="ICSharpCode.Decompiler.Tests.TestCases.PdbGen\HelloWorld.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
+    <file id="1" name="ICSharpCode\Decompiler\Tests\TestCases\PdbGen\HelloWorld.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.PdbGen
 {

ICSharpCode.Decompiler.Tests/TestCases/PdbGen/LambdaCapturing.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <symbols>
   <files>
-    <file id="1" name="ICSharpCode.Decompiler.Tests.TestCases.PdbGen\LambdaCapturing.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
+    <file id="1" name="ICSharpCode\Decompiler\Tests\TestCases\PdbGen\LambdaCapturing.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.PdbGen
 {

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

@@ -0,0 +1,50 @@
+namespace ICSharpCode.Decompiler.Tests.TestCases.CovariantReturns
+{
+	public abstract class Base
+	{
+		public abstract Base Instance { get; }
+
+		public abstract Base this[int index] { get; }
+
+		public virtual Base Build()
+		{
+			throw null;
+		}
+
+		protected abstract Base SetParent(object parent);
+	}
+
+	public class Derived : Base
+	{
+		public override Derived Instance { get; }
+
+		public override Derived this[int index] {
+			get {
+				throw null;
+			}
+		}
+
+		public override Derived Build()
+		{
+			throw null;
+		}
+
+		protected override Derived SetParent(object parent)
+		{
+			throw null;
+		}
+	}
+
+	public class UseSites
+	{
+		public Base Test(Base x)
+		{
+			return x.Build();
+		}
+
+		public Derived Test(Derived x)
+		{
+			return x.Build();
+		}
+	}
+}

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

@@ -32,6 +32,11 @@ public interface IA
 			void Method();
 
 #if CS80
+			static IA()
+			{
+
+			}
+
 			void DefaultMethod()
 			{
 				Method();

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -1453,9 +1453,24 @@ EntityDeclaration DoDecompile(IMethod method, DecompileRun decompileRun, ITypeRe
 			{
 				SetNewModifier(methodDecl);
 			}
+			if (IsCovariantReturnOverride(method))
+			{
+				RemoveAttribute(methodDecl, KnownAttribute.PreserveBaseOverrides);
+				methodDecl.Modifiers &= ~(Modifiers.New | Modifiers.Virtual);
+				methodDecl.Modifiers |= Modifiers.Override;
+			}
 			return methodDecl;
 		}
 
+		private bool IsCovariantReturnOverride(IEntity entity)
+		{
+			if (!settings.CovariantReturns)
+				return false;
+			if (!entity.HasAttribute(KnownAttribute.PreserveBaseOverrides))
+				return false;
+			return true;
+		}
+
 		internal static bool IsWindowsFormsInitializeComponentMethod(IMethod method)
 		{
 			return method.ReturnType.Kind == TypeKind.Void && method.Name == "InitializeComponent" && method.DeclaringTypeDefinition.GetNonInterfaceBaseTypes().Any(t => t.FullName == "System.Windows.Forms.Control");
@@ -1768,7 +1783,15 @@ EntityDeclaration DoDecompile(IProperty property, DecompileRun decompileRun, ITy
 				var accessorHandle = (MethodDefinitionHandle)(property.Getter ?? property.Setter).MetadataToken;
 				var accessor = metadata.GetMethodDefinition(accessorHandle);
 				if (!accessorHandle.GetMethodImplementations(metadata).Any() && accessor.HasFlag(System.Reflection.MethodAttributes.Virtual) == accessor.HasFlag(System.Reflection.MethodAttributes.NewSlot))
+				{
 					SetNewModifier(propertyDecl);
+				}
+				if (getterHasBody && IsCovariantReturnOverride(property.Getter))
+				{
+					RemoveAttribute(getter, KnownAttribute.PreserveBaseOverrides);
+					propertyDecl.Modifiers &= ~(Modifiers.New | Modifiers.Virtual);
+					propertyDecl.Modifiers |= Modifiers.Override;
+				}
 				return propertyDecl;
 			}
 			catch (Exception innerException) when (!(innerException is OperationCanceledException || innerException is DecompilerException))

ICSharpCode.Decompiler/CSharp/CallBuilder.cs

@@ -1148,7 +1148,7 @@ private ExpressionWithResolveResult HandleImplicitConversion(IMethod method, Tra
 			var conversions = CSharpConversions.Get(expressionBuilder.compilation);
 			IType targetType = method.ReturnType;
 			var conv = conversions.ImplicitConversion(argument.Type, targetType);
-			if (!(conv.IsUserDefined && conv.Method.Equals(method)))
+			if (!(conv.IsUserDefined && conv.IsValid && conv.Method.Equals(method)))
 			{
 				// implicit conversion to targetType isn't directly possible, so first insert a cast to the argument type
 				argument = argument.ConvertTo(method.Parameters[0].Type, expressionBuilder);

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -1618,7 +1618,7 @@ IType FindType(StackType stackType, Sign sign)
 			}
 			else
 			{
-				return compilation.FindType(stackType.ToKnownTypeCode(sign));
+				return compilation.FindType(stackType, sign);
 			}
 		}
 
@@ -1644,7 +1644,7 @@ IType FindArithmeticType(StackType stackType, Sign sign)
 					stackType = StackType.I8;
 				}
 			}
-			return compilation.FindType(stackType.ToKnownTypeCode(sign));
+			return compilation.FindType(stackType, sign);
 		}
 
 		/// <summary>
@@ -3568,7 +3568,7 @@ protected internal override TranslatedExpression VisitNullCoalescingInstruction(
 				}
 				else if (!value.Type.Equals(SpecialType.NullType) && !fallback.Type.Equals(SpecialType.NullType) && !value.Type.Equals(fallback.Type))
 				{
-					targetType = compilation.FindType(inst.UnderlyingResultType.ToKnownTypeCode());
+					targetType = compilation.FindType(inst.UnderlyingResultType);
 				}
 				else
 				{
@@ -3731,7 +3731,7 @@ protected internal override TranslatedExpression VisitSwitchInstruction(SwitchIn
 			}
 			else
 			{
-				resultType = compilation.FindType(inst.ResultType.ToKnownTypeCode());
+				resultType = compilation.FindType(inst.ResultType);
 			}
 
 			foreach (var section in inst.Sections)