Add interface implementation analyzer and tests

The analyzer can be used on any non-static members of classes and
structs. The analyzer shows a new 'Implements' node for those members
that implement an interface (implicitly or explicitly). Abstract members
are considered as implementation. Overridden virtual members of base
classes are not considered.

ILSpy.Tests/Analyzers/MemberImplementsInterfaceAnalyzerTests.cs

@@ -0,0 +1,186 @@
+// Copyright (c) 2020 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.IO;
+using System.Linq;
+using System.Reflection.Metadata;
+using System.Reflection.PortableExecutable;
+using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.Decompiler.TypeSystem.Implementation;
+using ICSharpCode.ILSpy.Analyzers;
+using ICSharpCode.ILSpy.Analyzers.Builtin;
+using Moq;
+using NUnit.Framework;
+
+namespace ICSharpCode.ILSpy.Tests.Analyzers
+{
+	[TestFixture, Parallelizable(ParallelScope.All)]
+	public class MemberImplementsInterfaceAnalyzerTests
+	{
+		static readonly SymbolKind[] ValidSymbolKinds = { SymbolKind.Event, SymbolKind.Indexer, SymbolKind.Method, SymbolKind.Property };
+		static readonly SymbolKind[] InvalidSymbolKinds =
+			Enum.GetValues(typeof(SymbolKind)).Cast<SymbolKind>().Except(ValidSymbolKinds).ToArray();
+
+		static readonly TypeKind[] ValidTypeKinds = { TypeKind.Class, TypeKind.Struct };
+		static readonly TypeKind[] InvalidTypeKinds = Enum.GetValues(typeof(TypeKind)).Cast<TypeKind>().Except(ValidTypeKinds).ToArray();
+		
+		private ICompilation testAssembly;
+
+		[OneTimeSetUp]
+		public void Setup()
+		{
+			string fileName = GetType().Assembly.Location;
+
+			using (var stream = new FileStream(fileName, FileMode.Open, FileAccess.Read)) {
+				var module = new PEFile(fileName, stream, PEStreamOptions.PrefetchEntireImage, MetadataReaderOptions.None);
+
+				testAssembly = new SimpleCompilation(module.WithOptions(TypeSystemOptions.Default), MinimalCorlib.Instance);
+			}
+		}
+
+		[Test]
+		public void VerifyDoesNotShowForNoSymbol()
+		{
+			// Arrange
+			var analyzer = new MemberImplementsInterfaceAnalyzer();
+
+			// Act
+			var shouldShow = analyzer.Show(symbol: null);
+			
+			// Assert
+			Assert.IsFalse(shouldShow, $"The analyzer will be unexpectedly shown for no symbol");
+		}
+
+		[Test]
+		[TestCaseSource(nameof(InvalidSymbolKinds))]
+		public void VerifyDoesNotShowForNonMembers(SymbolKind symbolKind)
+		{
+			// Arrange
+			var symbolMock = new Mock<ISymbol>();
+			symbolMock.Setup(s => s.SymbolKind).Returns(symbolKind);
+			var analyzer = new MemberImplementsInterfaceAnalyzer();
+
+			// Act
+			var shouldShow = analyzer.Show(symbolMock.Object);
+
+			// Assert
+			Assert.IsFalse(shouldShow, $"The analyzer will be unexpectedly shown for symbol '{symbolKind}'");
+		}
+
+		[Test]
+		[TestCaseSource(nameof(ValidSymbolKinds))]
+		public void VerifyDoesNotShowForStaticMembers(SymbolKind symbolKind)
+		{
+			// Arrange
+			var memberMock = SetupMemberMock(symbolKind, TypeKind.Unknown, isStatic: true);
+			var analyzer = new MemberImplementsInterfaceAnalyzer();
+
+			// Act
+			var shouldShow = analyzer.Show(memberMock.Object);
+
+			// Assert
+			Assert.IsFalse(shouldShow, $"The analyzer will be unexpectedly shown for static symbol '{symbolKind}'");
+		}
+
+		[Test]
+		[Pairwise]
+		public void VerifyDoesNotShowForUnsupportedTypes(
+			[ValueSource(nameof(ValidSymbolKinds))] SymbolKind symbolKind,
+			[ValueSource(nameof(InvalidTypeKinds))] TypeKind typeKind)
+		{
+			// Arrange
+			var memberMock = SetupMemberMock(symbolKind, typeKind, isStatic: true);
+			var analyzer = new MemberImplementsInterfaceAnalyzer();
+
+			// Act
+			var shouldShow = analyzer.Show(memberMock.Object);
+
+			// Assert
+			Assert.IsFalse(shouldShow, $"The analyzer will be unexpectedly shown for symbol '{symbolKind}' and '{typeKind}'");
+		}
+
+		[Test]
+		[Pairwise]
+		public void VerifyShowsForSupportedTypes(
+			[ValueSource(nameof(ValidSymbolKinds))] SymbolKind symbolKind,
+			[ValueSource(nameof(ValidTypeKinds))] TypeKind typeKind)
+		{
+			// Arrange
+			var memberMock = SetupMemberMock(symbolKind, typeKind, isStatic: false);
+			var analyzer = new MemberImplementsInterfaceAnalyzer();
+
+			// Act
+			var shouldShow = analyzer.Show(memberMock.Object);
+
+			// Assert
+			Assert.IsTrue(shouldShow, $"The analyzer will not be shown for symbol '{symbolKind}' and '{typeKind}'");
+		}
+
+		[Test]
+		public void VerifyReturnsOnlyInterfaceMembers()
+		{
+			// Arrange
+			var symbol = SetupSymbolForAnalysis(typeof(TestClass), nameof(TestClass.TestMethod));
+			var analyzer = new MemberImplementsInterfaceAnalyzer();
+
+			// Act
+			var results = analyzer.Analyze(symbol, new AnalyzerContext());
+
+			// Assert
+			Assert.IsNotNull(results);
+			Assert.AreEqual(1, results.Count());
+			var result = results.FirstOrDefault() as IMethod;
+			Assert.IsNotNull(result);
+			Assert.IsNotNull(result.DeclaringTypeDefinition);
+			Assert.AreEqual(TypeKind.Interface, result.DeclaringTypeDefinition.Kind);
+			Assert.AreEqual(nameof(ITestInterface), result.DeclaringTypeDefinition.Name);
+		}
+
+		private ISymbol SetupSymbolForAnalysis(Type type, string methodName)
+		{
+			var typeDefinition = testAssembly.FindType(type).GetDefinition();
+			return typeDefinition.Methods.First(m => m.Name == methodName);
+		}
+
+		private static Mock<IMember> SetupMemberMock(SymbolKind symbolKind, TypeKind typeKind, bool isStatic)
+        {
+			var memberMock = new Mock<IMember>();
+			memberMock.Setup(m => m.SymbolKind).Returns(symbolKind);
+			memberMock.Setup(m => m.DeclaringTypeDefinition.Kind).Returns(typeKind);
+			memberMock.Setup(m => m.IsStatic).Returns(isStatic);
+			return memberMock;
+		}
+
+		private interface ITestInterface
+		{
+			void TestMethod();
+		}
+
+		private class BaseClass
+		{
+			public virtual void TestMethod() => throw new NotImplementedException();
+		}
+
+		private class TestClass : BaseClass, ITestInterface
+		{
+			public override void TestMethod() => throw new NotImplementedException();
+		}
+	}
+}

ILSpy.Tests/ILSpy.Tests.csproj

@@ -37,6 +37,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <Compile Include="Analyzers\MemberImplementsInterfaceAnalyzerTests.cs" />
     <Compile Include="Analyzers\MethodUsesAnalyzerTests.cs" />
     <Compile Include="Analyzers\TestCases\MainAssembly.cs" />
     <Compile Include="Analyzers\TypeUsedByAnalyzerTests.cs" />

ILSpy/Analyzers/Builtin/MemberImplementsInterfaceAnalyzer.cs

@@ -0,0 +1,59 @@
+// 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.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using ICSharpCode.Decompiler.TypeSystem;
+
+namespace ICSharpCode.ILSpy.Analyzers.Builtin
+{
+	/// <summary>
+	/// Shows members from all corresponding interfaces the selected member implements.
+	/// </summary>
+	[ExportAnalyzer(Header = "Implements", Order = 40)]
+	class MemberImplementsInterfaceAnalyzer : IAnalyzer
+	{
+		public IEnumerable<ISymbol> Analyze(ISymbol analyzedSymbol, AnalyzerContext context)
+		{
+			Debug.Assert(analyzedSymbol is IMember);
+			var member = (IMember)analyzedSymbol;
+
+			Debug.Assert(!member.IsStatic);
+
+			var baseMembers = InheritanceHelper.GetBaseMembers(member, includeImplementedInterfaces: true);
+			return baseMembers.Where(m => m.DeclaringTypeDefinition.Kind == TypeKind.Interface);
+		}
+
+		public bool Show(ISymbol symbol)
+		{
+			switch (symbol?.SymbolKind) {
+				case SymbolKind.Event:
+				case SymbolKind.Indexer:
+				case SymbolKind.Method:
+				case SymbolKind.Property:
+					var member = (IMember)symbol;
+					var type = member.DeclaringTypeDefinition;
+					return !member.IsStatic && (type.Kind == TypeKind.Class || type.Kind == TypeKind.Struct);
+
+				default:
+					return false;
+			}
+		}
+	}
+}

ILSpy/ILSpy.csproj

@@ -80,6 +80,7 @@
     <Compile Include="Analyzers\Builtin\EventImplementedByAnalyzer.cs" />
     <Compile Include="Analyzers\Builtin\EventOverriddenByAnalyzer.cs" />
     <Compile Include="Analyzers\Builtin\MethodImplementedByAnalyzer.cs" />
+    <Compile Include="Analyzers\Builtin\MemberImplementsInterfaceAnalyzer.cs" />
     <Compile Include="Analyzers\Builtin\MethodOverriddenByAnalyzer.cs" />
     <Compile Include="Analyzers\Builtin\MethodVirtualUsedByAnalyzer.cs" />
     <Compile Include="Analyzers\Builtin\MethodUsedByAnalyzer.cs" />