Fix bug in ParameterListComparer: the method signatures "Method<T>(T a)" and "Method<S>(S b)" were considered unequal.

ICSharpCode.NRefactory.CSharp/Resolver/MethodGroupResolveResult.cs

@@ -100,8 +100,9 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		}
 		
 		/// <summary>
-		/// Gets the methods that were found.
+		/// Gets the methods that were found, grouped by their declaring type.
 		/// This list does not include extension methods.
+		/// Base types come first in the list.
 		/// </summary>
 		public IEnumerable<MethodListWithDeclaringType> MethodsGroupedByDeclaringType {
 			get { return methodLists; }

ICSharpCode.NRefactory.CSharp/Resolver/OverloadResolution.cs

@@ -235,6 +235,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		/// This method implements the logic that causes applicable methods in derived types to hide
 		/// all methods in base types.
 		/// </summary>
+		/// <param name="methodLists">The methods, grouped by declaring type. Base types must come first in the list.</param>
 		public void AddMethodLists(IList<MethodListWithDeclaringType> methodLists)
 		{
 			if (methodLists == null)

ICSharpCode.NRefactory.Tests/CSharp/Resolver/MemberLookupTests.cs

@@ -0,0 +1,125 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
+// 
+// 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 ICSharpCode.NRefactory.Semantics;
+using ICSharpCode.NRefactory.TypeSystem;
+using NUnit.Framework;
+
+namespace ICSharpCode.NRefactory.CSharp.Resolver
+{
+	[TestFixture]
+	public class MemberLookupTests : ResolverTestBase
+	{
+		MemberLookup lookup;
+		
+		public override void SetUp()
+		{
+			base.SetUp();
+			lookup = new MemberLookup(context, null, project);
+		}
+		
+		CSharpParsedFile Parse(string program)
+		{
+			CompilationUnit cu = new CSharpParser().Parse(new StringReader(program));
+			CSharpParsedFile parsedFile = new TypeSystemConvertVisitor(project, "test.cs").Convert(cu);
+			project.UpdateProjectContent(null, parsedFile);
+			return parsedFile;
+		}
+		
+		[Test]
+		public void GroupMethodsByDeclaringType()
+		{
+			string program = @"
+class Base {
+	public virtual void Method() {}
+}
+class Middle : Base {
+	public void Method(int p) {}
+}
+class Derived : Middle {
+	public override void Method() {}
+}";
+			ITypeDefinition derived = Parse(program).TopLevelTypeDefinitions[2];
+			var rr = lookup.Lookup(new ResolveResult(derived), "Method", EmptyList<IType>.Instance, true) as MethodGroupResolveResult;
+			Assert.AreEqual(2, rr.MethodsGroupedByDeclaringType.Count());
+			
+			var baseGroup = rr.MethodsGroupedByDeclaringType.ElementAt(0);
+			Assert.AreEqual("Base", baseGroup.DeclaringType.ReflectionName);
+			Assert.AreEqual(1, baseGroup.Count);
+			Assert.AreEqual("Derived.Method", baseGroup[0].FullName);
+			
+			var middleGroup = rr.MethodsGroupedByDeclaringType.ElementAt(1);
+			Assert.AreEqual("Middle", middleGroup.DeclaringType.ReflectionName);
+			Assert.AreEqual(1, middleGroup.Count);
+			Assert.AreEqual("Middle.Method", middleGroup[0].FullName);
+		}
+		
+		[Test]
+		public void MethodInGenericClassOverriddenByConcreteMethod()
+		{
+			string program = @"
+class Base<T> {
+	public virtual void Method(T a) {}
+}
+class Derived : Base<int> {
+	public override void Method(int a) {}
+	public override void Method(string a) {}
+}";
+			ITypeDefinition derived = Parse(program).TopLevelTypeDefinitions[1];
+			var rr = lookup.Lookup(new ResolveResult(derived), "Method", EmptyList<IType>.Instance, true) as MethodGroupResolveResult;
+			Assert.AreEqual(2, rr.MethodsGroupedByDeclaringType.Count());
+			
+			var baseGroup = rr.MethodsGroupedByDeclaringType.ElementAt(0);
+			Assert.AreEqual("Base`1[[System.Int32]]", baseGroup.DeclaringType.ReflectionName);
+			Assert.AreEqual(1, baseGroup.Count);
+			Assert.AreEqual("Derived.Method", baseGroup[0].FullName);
+			Assert.AreEqual("System.Int32", baseGroup[0].Parameters[0].Type.Resolve(context).ReflectionName);
+			
+			var derivedGroup = rr.MethodsGroupedByDeclaringType.ElementAt(1);
+			Assert.AreEqual("Derived", derivedGroup.DeclaringType.ReflectionName);
+			Assert.AreEqual(1, derivedGroup.Count);
+			Assert.AreEqual("Derived.Method", derivedGroup[0].FullName);
+			Assert.AreEqual("System.String", derivedGroup[0].Parameters[0].Type.Resolve(context).ReflectionName);
+		}
+		
+		[Test]
+		public void GenericMethod()
+		{
+			string program = @"
+class Base {
+	public virtual void Method<T>(T a) {}
+}
+class Derived : Base {
+	public override void Method<S>(S a) {}
+}";
+			ITypeDefinition derived = Parse(program).TopLevelTypeDefinitions[1];
+			var rr = lookup.Lookup(new ResolveResult(derived), "Method", EmptyList<IType>.Instance, true) as MethodGroupResolveResult;
+			Assert.AreEqual(1, rr.MethodsGroupedByDeclaringType.Count());
+			
+			var baseGroup = rr.MethodsGroupedByDeclaringType.ElementAt(0);
+			Assert.AreEqual("Base", baseGroup.DeclaringType.ReflectionName);
+			Assert.AreEqual(1, baseGroup.Count);
+			Assert.AreEqual("Derived.Method", baseGroup[0].FullName);
+			Assert.AreEqual("``0", baseGroup[0].Parameters[0].Type.Resolve(context).ReflectionName);
+		}
+	}
+}

ICSharpCode.NRefactory.Tests/CSharp/Resolver/ResolverTestBase.cs

@@ -197,7 +197,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			SetUp();
 			
 			CSharpParsedFile parsedFile = new CSharpParsedFile("test.cs", resolver.CurrentUsingScope);
-			TypeSystemConvertVisitor convertVisitor = new TypeSystemConvertVisitor(parsedFile, resolver.CurrentUsingScope, null);
+			TypeSystemConvertVisitor convertVisitor = new TypeSystemConvertVisitor(parsedFile);
 			cu.AcceptVisitor(convertVisitor, null);
 			project.UpdateProjectContent(null, convertVisitor.ParsedFile);
 			

ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj

@@ -154,6 +154,7 @@
     <Compile Include="CSharp\Resolver\LambdaTests.cs" />
     <Compile Include="CSharp\Resolver\LinqTests.cs" />
     <Compile Include="CSharp\Resolver\LocalTypeInferenceTests.cs" />
+    <Compile Include="CSharp\Resolver\MemberLookupTests.cs" />
     <Compile Include="CSharp\Resolver\NameLookupTests.cs" />
     <Compile Include="CSharp\Resolver\ObjectCreationTests.cs" />
     <Compile Include="CSharp\Resolver\ResolveAtLocationTests.cs" />

ICSharpCode.NRefactory.Tests/TypeSystem/TypeSystemTests.cs

@@ -431,8 +431,8 @@ namespace ICSharpCode.NRefactory.TypeSystem
 			Assert.IsFalse(type.TypeParameters[0].HasReferenceTypeConstraint);
 			Assert.IsTrue(type.TypeParameters[1].HasReferenceTypeConstraint);
 			
-			Assert.IsTrue(type.TypeParameters[0].IsReferenceType(ctx) == true);
-			Assert.IsTrue(type.TypeParameters[1].IsReferenceType(ctx) == true);
+			Assert.IsNull(type.TypeParameters[0].IsReferenceType(ctx));
+			Assert.AreEqual(true, type.TypeParameters[1].IsReferenceType(ctx));
 		}
 		
 		[Test]

ICSharpCode.NRefactory/TypeSystem/ExtensionMethods.cs

@@ -37,7 +37,7 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		/// Note that this method does not return all supertypes - doing so is impossible due to contravariance
 		/// (and undesirable for covariance as the list could become very large).
 		/// 
-		/// The output is ordered so that base types occur in before derived types.
+		/// The output is ordered so that base types occur before derived types.
 		/// </remarks>
 		public static IEnumerable<IType> GetAllBaseTypes(this IType type, ITypeResolveContext context)
 		{
@@ -47,12 +47,12 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		}
 		
 		/// <summary>
-		/// Gets the non-interface base types.
+		/// Gets all non-interface base types.
 		/// </summary>
 		/// <remarks>
-		/// When <paramref name="type"/> is an interface, this method will also return base interfaces.
+		/// When <paramref name="type"/> is an interface, this method will also return base interfaces (return same output as GetAllBaseTypes()).
 		/// 
-		/// The output is ordered so that base types occur in before derived types.
+		/// The output is ordered so that base types occur before derived types.
 		/// </remarks>
 		public static IEnumerable<IType> GetNonInterfaceBaseTypes(this IType type, ITypeResolveContext context)
 		{

ICSharpCode.NRefactory/TypeSystem/ParameterListComparer.cs

@@ -18,11 +18,51 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
+using ICSharpCode.NRefactory.TypeSystem.Implementation;
 
 namespace ICSharpCode.NRefactory.TypeSystem
 {
 	public static class ParameterListComparer
 	{
+		// We want to consider the parameter lists "Method<T>(T a)" and "Method<S>(S b)" as equal.
+		// However, the parameter types are not considered equal, as T is a different type parameter than S.
+		// In order to compare the method signatures, we will normalize all method type parameters.
+		sealed class NormalizeMethodTypeParameters : TypeVisitor
+		{
+			public static readonly NormalizeMethodTypeParameters Instance = new NormalizeMethodTypeParameters();
+			
+			ITypeParameter[] normalTypeParameters = { new DefaultTypeParameter(EntityType.Method, 0, string.Empty) };
+			
+			public override IType VisitTypeParameter(ITypeParameter type)
+			{
+				if (type.OwnerType == EntityType.Method) {
+					ITypeParameter[] tps = this.normalTypeParameters;
+					while (type.Index >= tps.Length) {
+						// We don't have a normal type parameter for this index, so we need to extend our array.
+						// Because the array can be used concurrently from multiple threads, we have to use
+						// Interlocked.CompareExchange.
+						ITypeParameter[] newTps = new ITypeParameter[type.Index + 1];
+						tps.CopyTo(newTps, 0);
+						for (int i = tps.Length; i < newTps.Length; i++) {
+							newTps[i] = new DefaultTypeParameter(EntityType.Method, i, string.Empty);
+						}
+						ITypeParameter[] oldTps = Interlocked.CompareExchange(ref normalTypeParameters, newTps, tps);
+						if (oldTps == tps) {
+							// exchange successful
+							tps = newTps;
+						} else {
+							// exchange not successful
+							tps = oldTps;
+						}
+					}
+					return tps[type.Index];
+				} else {
+					return base.VisitTypeParameter(type);
+				}
+			}
+		}
+		
 		public static bool Compare(ITypeResolveContext context, IParameterizedMember x, IParameterizedMember y)
 		{
 			var px = x.Parameters;
@@ -36,7 +76,13 @@ namespace ICSharpCode.NRefactory.TypeSystem
 					continue;
 				if (a == null || b == null)
 					return false;
-				if (!a.Type.Resolve(context).Equals(b.Type.Resolve(context)))
+				IType aType = a.Type.Resolve(context);
+				IType bType = b.Type.Resolve(context);
+				
+				aType = aType.AcceptVisitor(NormalizeMethodTypeParameters.Instance);
+				bType = bType.AcceptVisitor(NormalizeMethodTypeParameters.Instance);
+				
+				if (!aType.Equals(bType))
 					return false;
 			}
 			return true;
@@ -48,7 +94,9 @@ namespace ICSharpCode.NRefactory.TypeSystem
 			unchecked {
 				foreach (IParameter p in obj.Parameters) {
 					hashCode *= 27;
-					hashCode += p.Type.Resolve(context).GetHashCode();
+					IType type = p.Type.Resolve(context);
+					type = type.AcceptVisitor(NormalizeMethodTypeParameters.Instance);
+					hashCode += type.GetHashCode();
 				}
 			}
 			return hashCode;