Add InvocationResolveResult.

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

@@ -40,18 +40,18 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		public void AttributeConstructor1()
 		{
 			string program = "using System; [$LoaderOptimization(3)$] class Test { }";
-			var mrr = Resolve<MemberResolveResult>(program);
+			var mrr = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("System.LoaderOptimizationAttribute..ctor", mrr.Member.FullName);
-			Assert.AreEqual("System.Byte", (mrr.Member as IMethod).Parameters[0].Type.Resolve(context).FullName);
+			Assert.AreEqual("System.Byte", mrr.Member.Parameters[0].Type.Resolve(context).FullName);
 		}
 		
 		[Test]
 		public void AttributeConstructor2()
 		{
 			string program = "using System; [$LoaderOptimization(LoaderOptimization.NotSpecified)$] class Test { }";
-			var mrr = Resolve<MemberResolveResult>(program);
+			var mrr = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("System.LoaderOptimizationAttribute..ctor", mrr.Member.FullName);
-			Assert.AreEqual("System.LoaderOptimization", (mrr.Member as IMethod).Parameters[0].Type.Resolve(context).FullName);
+			Assert.AreEqual("System.LoaderOptimization", mrr.Member.Parameters[0].Type.Resolve(context).FullName);
 		}
 		
 		[Test]
@@ -59,7 +59,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		{
 			string program = "using System; [$Obsolete$] class Test {}";
 			
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			var result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("System.ObsoleteAttribute..ctor", result.Member.FullName);
 		}
 		
@@ -71,7 +71,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 	public const AttributeTargets XXX = AttributeTargets.All;
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			var result = Resolve<MemberResolveResult>(program);
 			Assert.AreEqual("MyAttribute.XXX", result.Member.FullName);
 		}
 		
@@ -83,7 +83,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 enum E { A, B }
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			var result = Resolve<MemberResolveResult>(program);
 			Assert.AreEqual("MyNamespace.E.A", result.Member.FullName);
 		}
 		

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

@@ -33,31 +33,31 @@ namespace XN {
 	}
 }
 ";
-			MemberResolveResult mrr;
+			InvocationResolveResult mrr;
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$a.F(1)$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$a.F(1)$"));
 			Assert.AreEqual("XN.XC.F", mrr.Member.FullName);
-			Assert.AreEqual("System.Int32", ((IMethod)mrr.Member).Parameters[1].Type.Resolve(context).FullName);
+			Assert.AreEqual("System.Int32", mrr.Member.Parameters[1].Type.Resolve(context).FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$a.F(\"text\")$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$a.F(\"text\")$"));
 			Assert.AreEqual("XN.XC.F", mrr.Member.FullName);
-			Assert.AreEqual("System.String", ((IMethod)mrr.Member).Parameters[1].Type.Resolve(context).FullName);
+			Assert.AreEqual("System.String", mrr.Member.Parameters[1].Type.Resolve(context).FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$b.F(1)$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$b.F(1)$"));
 			Assert.AreEqual("B.F", mrr.Member.FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$b.F(\"text\")$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$b.F(\"text\")$"));
 			Assert.AreEqual("XN.XC.F", mrr.Member.FullName);
-			Assert.AreEqual("System.String", ((IMethod)mrr.Member).Parameters[1].Type.Resolve(context).FullName);
+			Assert.AreEqual("System.String", mrr.Member.Parameters[1].Type.Resolve(context).FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$c.F(1)$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$c.F(1)$"));
 			Assert.AreEqual("C.F", mrr.Member.FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$c.F(\"text\")$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$c.F(\"text\")$"));
 			Assert.AreEqual("C.F", mrr.Member.FullName);
 		}
 		
-		[Test, Ignore("Anonymous methods not yet implemented")]
+		[Test]
 		public void ExtensionMethodsTest2()
 		{
 			string program = @"using System; using System.Collections.Generic;
@@ -72,18 +72,18 @@ public static class XC {
 	public static IEnumerable<T> Filter<T>(this IEnumerable<T> source, Predicate<T> predicate) { throw new NotImplementedException(); }
 }
 ";
-			MemberResolveResult mrr;
+			InvocationResolveResult mrr;
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$\"text\".ToInt32()$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$\"text\".ToInt32()$"));
 			Assert.AreEqual("XC.ToInt32", mrr.Member.FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$args.Slice(1, 2)$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$args.Slice(1, 2)$"));
 			Assert.AreEqual("XC.Slice", mrr.Member.FullName);
 			Assert.AreEqual("System.String[]", mrr.Type.ReflectionName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$args.Filter(delegate { return true; })$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$args.Filter(delegate { return true; })$"));
 			Assert.AreEqual("XC.Filter", mrr.Member.FullName);
-			Assert.AreEqual("System.Collections.Generic.IEnumerable{System.String}", mrr.Type.ReflectionName);
+			Assert.AreEqual("System.Collections.Generic.IEnumerable`1[[System.String]]", mrr.Type.ReflectionName);
 		}
 	}
 }

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

@@ -25,7 +25,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 	}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("A.TargetMethod", result.Member.FullName);
 			Assert.AreEqual("System.Int32", result.Type.ReflectionName);
 		}
@@ -66,7 +66,7 @@ class B : A {
 	}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("B.GetRandomNumber", result.Member.FullName);
 		}
 		
@@ -87,7 +87,7 @@ class B : A {
 	}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("B.GetRandomNumber", result.Member.FullName);
 		}
 		
@@ -104,7 +104,7 @@ class B : A {
 	}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("A.TargetMethod", result.Member.FullName);
 			Assert.AreEqual("System.Int32", result.Type.ReflectionName);
 		}
@@ -202,11 +202,11 @@ class Program {
 	static void T(ref int y) {}
 }";
 			
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program, "T(a)");
-			Assert.IsFalse(((IMethod)mrr.Member).Parameters[0].IsRef);
+			InvocationResolveResult mrr = Resolve<InvocationResolveResult>(program, "T(a)");
+			Assert.IsFalse(mrr.Member.Parameters[0].IsRef);
 			
-			mrr = Resolve<MemberResolveResult>(program, "T(ref a)");
-			Assert.IsTrue(((IMethod)mrr.Member).Parameters[0].IsRef);
+			mrr = Resolve<InvocationResolveResult>(program, "T(ref a)");
+			Assert.IsTrue(mrr.Member.Parameters[0].IsRef);
 		}
 		
 		[Test, Ignore("Grouping by declaring type not yet implemented")]
@@ -221,7 +221,7 @@ class Program {
 class DerivedClass : BaseClass {
 	public void Test(object a) { }
 }";
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult mrr = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("DerivedClass.Test", mrr.Member.FullName);
 		}
 		
@@ -237,10 +237,10 @@ class DerivedClass : BaseClass {
 class DerivedClass : BaseClass {
 	public void Test(string a) { }
 }";
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult mrr = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("BaseClass.Test", mrr.Member.FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program.Replace("(3)", "(\"3\")"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("(3)", "(\"3\")"));
 			Assert.AreEqual("DerivedClass.Test", mrr.Member.FullName);
 		}
 		
@@ -261,7 +261,7 @@ class DerivedClass : MiddleClass {
 	public override void Test(int a) { }
 }";
 			
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult mrr = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("MiddleClass.Test", mrr.Member.FullName);
 		}
 	}

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

@@ -408,7 +408,7 @@ class TestClass {
 ";
 			TypeResolveResult trr = Resolve<TypeResolveResult>(program.Replace("COL a", "$COL$ a"));
 			Assert.AreEqual("System.Collections.ArrayList", trr.Type.FullName, "COL");
-			ResolveResult rr = Resolve<ResolveResult>(program.Replace("new COL()", "$new COL()$"));
+			ResolveResult rr = Resolve<InvocationResolveResult>(program.Replace("new COL()", "$new COL()$"));
 			Assert.AreEqual("System.Collections.ArrayList", rr.Type.FullName, "a");
 		}
 		
@@ -539,7 +539,7 @@ class TestClass {
 			trr = Resolve<TypeResolveResult>(program.Replace("$", "$global::XX.XX$"));
 			Assert.AreEqual("XX.XX", trr.Type.FullName);
 			
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program.Replace("$", "$XX.Test()$"));
+			InvocationResolveResult mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$XX.Test()$"));
 			Assert.AreEqual("XX.XX.Test", mrr.Member.FullName);
 		}
 		
@@ -651,7 +651,7 @@ namespace A {
 	class BaseClass {
 		public static string Test() {}
 	}";
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program.Replace("$", "$BaseClass.Test()$"));
+			MemberResolveResult mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$BaseClass.Test()$"));
 			Assert.AreEqual("BaseClass.Test", mrr.Member.FullName);
 			
 			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$Test$"));
@@ -661,7 +661,7 @@ namespace A {
 			Assert.AreEqual("DerivedClass.Test", mrr.Member.FullName);
 			
 			// returns BaseClass.Test because DerivedClass.Test is not invocable
-			mrr = Resolve<MemberResolveResult>(program.Replace("$", "$DerivedClass.Test()$"));
+			mrr = Resolve<InvocationResolveResult>(program.Replace("$", "$DerivedClass.Test()$"));
 			Assert.AreEqual("BaseClass.Test", mrr.Member.FullName);
 		}
 		

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

@@ -20,7 +20,7 @@ class A {
 	}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("System.Collections.Generic.List..ctor", result.Member.FullName);
 			
 			Assert.AreEqual("System.Collections.Generic.List`1[[System.String]]", result.Type.ReflectionName);
@@ -35,7 +35,7 @@ class A {
 	}
 }
 ";
-			ResolveResult result = Resolve<ResolveResult>(program);
+			ResolveResult result = Resolve<ErrorResolveResult>(program);
 			Assert.AreSame(SharedTypes.UnknownType, result.Type);
 		}
 		
@@ -67,21 +67,18 @@ class A {
 	A(double dblVal) {}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program.Replace("$", "$new A()$"));
-			IMethod m = (IMethod)result.Member;
-			Assert.IsFalse(m.IsStatic, "new A() is static");
-			Assert.AreEqual(0, m.Parameters.Count, "new A() parameter count");
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program.Replace("$", "$new A()$"));
+			Assert.IsFalse(result.Member.IsStatic, "new A() is static");
+			Assert.AreEqual(0, result.Member.Parameters.Count, "new A() parameter count");
 			Assert.AreEqual("A", result.Type.FullName);
 			
-			result = Resolve<MemberResolveResult>(program.Replace("$", "$new A(10)$"));
-			m = (IMethod)result.Member;
-			Assert.AreEqual(1, m.Parameters.Count, "new A(10) parameter count");
-			Assert.AreEqual("intVal", m.Parameters[0].Name, "new A(10) parameter");
+			result = Resolve<InvocationResolveResult>(program.Replace("$", "$new A(10)$"));
+			Assert.AreEqual(1, result.Member.Parameters.Count, "new A(10) parameter count");
+			Assert.AreEqual("intVal", result.Member.Parameters[0].Name, "new A(10) parameter");
 			
-			result = Resolve<MemberResolveResult>(program.Replace("$", "$new A(11.1)$"));
-			m = (IMethod)result.Member;
-			Assert.AreEqual(1, m.Parameters.Count, "new A(11.1) parameter count");
-			Assert.AreEqual("dblVal", m.Parameters[0].Name, "new A(11.1) parameter");
+			result = Resolve<InvocationResolveResult>(program.Replace("$", "$new A(11.1)$"));
+			Assert.AreEqual(1, result.Member.Parameters.Count, "new A(11.1) parameter count");
+			Assert.AreEqual("dblVal", result.Member.Parameters[0].Name, "new A(11.1) parameter");
 		}
 		
 		[Test]
@@ -93,11 +90,9 @@ class A {
 	}
 }
 ";
-			MemberResolveResult result = Resolve<MemberResolveResult>(program);
-			IMethod m = (IMethod)result.Member;
-			Assert.IsNotNull(m);
+			InvocationResolveResult result = Resolve<InvocationResolveResult>(program);
 			Assert.AreEqual("A", result.Type.ReflectionName);
-			Assert.AreEqual(0, m.Parameters.Count);
+			Assert.AreEqual(0, result.Member.Parameters.Count);
 		}
 		
 		[Test, Ignore("Parser returns incorrect positions")]
@@ -122,13 +117,13 @@ class C : B {
  	{}
 }
 ";
-			MemberResolveResult mrr = Resolve<MemberResolveResult>(program, "base(b)");
+			InvocationResolveResult mrr = Resolve<InvocationResolveResult>(program, "base(b)");
 			Assert.AreEqual("A..ctor", mrr.Member.FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program, "base(c)");
+			mrr = Resolve<InvocationResolveResult>(program, "base(c)");
 			Assert.AreEqual("B..ctor", mrr.Member.FullName);
 			
-			mrr = Resolve<MemberResolveResult>(program, "this(0)");
+			mrr = Resolve<InvocationResolveResult>(program, "this(0)");
 			Assert.AreEqual("C..ctor", mrr.Member.FullName);
 		}
 	}

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

@@ -171,7 +171,8 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		protected T Resolve<T>(string code) where T : ResolveResult
 		{
 			ResolveResult rr = Resolve(code);
-			Assert.IsTrue(rr is T, "Resolve should be " + typeof(T).Name + ", but was " + (rr != null ? rr.GetType().Name : "null"));
+			Assert.IsNotNull(rr);
+			Assert.IsTrue(rr.GetType() == typeof(T), "Resolve should be " + typeof(T).Name + ", but was " + rr.GetType().Name);
 			return (T)rr;
 		}
 		

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

@@ -86,7 +86,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			
 			ITypeDefinition declType = ctx.GetTypeDefinition(typeof(int));
 			var methods = declType.Methods.Where(m => m.Name == "Parse").ToList();
-			var argument = new MethodGroupResolveResult(declType, "Parse", methods, new IType[0]);
+			var argument = new MethodGroupResolveResult(new TypeResolveResult(declType), "Parse", methods, new IType[0]);
 			
 			bool success;
 			ti.InferTypeArguments(new [] { A, B }, new [] { argument },
@@ -105,7 +105,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			
 			ITypeDefinition declType = ctx.GetTypeDefinition(typeof(Console));
 			var methods = declType.Methods.Where(m => m.Name == "ReadKey").ToList();
-			var argument = new MethodGroupResolveResult(declType, "ReadKey", methods, new IType[0]);
+			var argument = new MethodGroupResolveResult(new TypeResolveResult(declType), "ReadKey", methods, new IType[0]);
 			
 			bool success;
 			Assert.AreEqual(
@@ -123,15 +123,21 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		{
 			IType[] expectedParameterTypes;
 			IType inferredReturnType;
+			IParameter[] parameters;
 			
 			public MockImplicitLambda(IType[] expectedParameterTypes, IType inferredReturnType)
 			{
 				this.expectedParameterTypes = expectedParameterTypes;
 				this.inferredReturnType = inferredReturnType;
+				this.parameters = new IParameter[expectedParameterTypes.Length];
+				for (int i = 0; i < parameters.Length; i++) {
+					// UnknownType because this lambda is implicitly typed
+					parameters[i] = new DefaultParameter(SharedTypes.UnknownType, "X" + i);
+				}
 			}
 			
 			public override IList<IParameter> Parameters {
-				get { throw new NotImplementedException(); }
+				get { return parameters; }
 			}
 			
 			public override Conversion IsValid(IType[] parameterTypes, IType returnType, Conversions conversions)

ICSharpCode.NRefactory/CSharp/Resolver/AmbiguousResolveResult.cs

@@ -22,7 +22,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 	
 	public class AmbiguousMemberResultResult : MemberResolveResult
 	{
-		public AmbiguousMemberResultResult(IMember member, IType returnType) : base(member, returnType)
+		public AmbiguousMemberResultResult(ResolveResult targetResult, IMember member, IType returnType) : base(targetResult, member, returnType)
 		{
 		}
 		

ICSharpCode.NRefactory/CSharp/Resolver/CSharpResolver.cs

@@ -1555,6 +1555,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					}
 				}
 			}
+			// TODO: return implicit/explicit conversion being applied
 			return new ResolveResult(targetType);
 		}
 		
@@ -1651,7 +1652,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				MemberLookup lookup = new MemberLookup(context, t, t.ProjectContent);
 				ResolveResult r;
 				if (lookupMode == SimpleNameLookupMode.Expression || lookupMode == SimpleNameLookupMode.InvocationTarget) {
-					r = lookup.Lookup(t, identifier, typeArguments, lookupMode == SimpleNameLookupMode.InvocationTarget);
+					r = lookup.Lookup(new TypeResolveResult(t), identifier, typeArguments, lookupMode == SimpleNameLookupMode.InvocationTarget);
 				} else {
 					r = lookup.LookupType(t, identifier, typeArguments, parameterizeResultType);
 				}
@@ -1785,11 +1786,11 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				return DynamicResult;
 			
 			MemberLookup lookup = CreateMemberLookup();
-			ResolveResult result = lookup.Lookup(target.Type, identifier, typeArguments, isInvocationTarget);
+			ResolveResult result = lookup.Lookup(target, identifier, typeArguments, isInvocationTarget);
 			if (result is UnknownMemberResolveResult) {
 				var extensionMethods = GetExtensionMethods(target.Type, identifier, typeArguments.Count);
 				if (extensionMethods.Count > 0) {
-					return new MethodGroupResolveResult(target.Type, identifier, EmptyList<IMethod>.Instance, typeArguments) {
+					return new MethodGroupResolveResult(target, identifier, EmptyList<IMethod>.Instance, typeArguments) {
 						extensionMethods = extensionMethods
 					};
 				}
@@ -1842,6 +1843,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			return extensionMethodGroups;
 		}
 		
+		/// <summary>
+		/// Gets all extension methods available in the current using scope.
+		/// This list includes unaccessible 
+		/// </summary>
 		List<List<IMethod>> GetAllExtensionMethods()
 		{
 			// TODO: maybe cache the result?
@@ -1873,7 +1878,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		{
 			return
 				from c in context.GetTypes(namespaceName, StringComparer.Ordinal)
-				where c.IsStatic && c.HasExtensionMethods
+				where c.IsStatic && c.HasExtensionMethods && c.TypeParameters.Count == 0
 				from m in c.Methods
 				where m.IsExtensionMethod
 				select m;
@@ -1894,9 +1899,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			if (mgrr != null) {
 				OverloadResolution or = mgrr.PerformOverloadResolution(context, arguments, argumentNames);
 				if (or.BestCandidate != null) {
-					IType returnType = or.BestCandidate.ReturnType.Resolve(context);
-					returnType = returnType.AcceptVisitor(new MethodTypeParameterSubstitution(or.InferredTypeArguments));
-					return new MemberResolveResult(or.BestCandidate, returnType);
+					return new InvocationResolveResult(mgrr.TargetResult, or, context);
 				} else {
 					// No candidate found at all (not even an inapplicable one).
 					// This can happen with empty method groups (as sometimes used with extension methods)
@@ -2019,7 +2022,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				or.AddCandidate(p);
 			}
 			if (or.BestCandidate != null) {
-				return new MemberResolveResult(or.BestCandidate, or.BestCandidate.ReturnType.Resolve(context));
+				return new InvocationResolveResult(target, or, context);
 			} else {
 				return ErrorResult;
 			}
@@ -2039,7 +2042,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				or.AddCandidate(ctor);
 			}
 			if (or.BestCandidate != null) {
-				return new MemberResolveResult(or.BestCandidate, type);
+				return new InvocationResolveResult(new TypeResolveResult(type), or, context);
 			} else {
 				return new ErrorResolveResult(type);
 			}

ICSharpCode.NRefactory/CSharp/Resolver/InvocationResolveResult.cs

@@ -0,0 +1,83 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the MIT license (for details please see \doc\license.txt)
+
+using System;
+using System.Collections.Generic;
+using ICSharpCode.NRefactory.TypeSystem;
+using ICSharpCode.NRefactory.TypeSystem.Implementation;
+
+namespace ICSharpCode.NRefactory.CSharp.Resolver
+{
+	/// <summary>
+	/// Represents the result of a method invocation.
+	/// </summary>
+	public class InvocationResolveResult : MemberResolveResult
+	{
+		public readonly OverloadResolutionErrors OverloadResolutionErrors;
+		public readonly IList<IType> TypeArguments;
+		
+		public readonly IList<ResolveResult> Arguments;
+		public readonly IList<Conversion> ArgumentConversions;
+		
+		/// <summary>
+		/// Gets whether this invocation is calling an extension method using extension method syntax.
+		/// </summary>
+		public readonly bool IsExtensionMethodInvocation;
+		
+		/// <summary>
+		/// Gets whether a params-Array is being used in its expanded form.
+		/// </summary>
+		public readonly bool IsExpandedForm;
+		
+		readonly IList<int> argumentToParameterMap;
+		
+		public InvocationResolveResult(ResolveResult targetResult, OverloadResolution or, ITypeResolveContext context)
+			: base(
+				or.IsExtensionMethodInvocation ? new TypeResolveResult(or.BestCandidate.DeclaringType) : targetResult,
+				or.BestCandidate,
+				GetReturnType(or, context))
+		{
+			this.OverloadResolutionErrors = or.BestCandidateErrors;
+			this.TypeArguments = or.InferredTypeArguments;
+			this.Arguments = or.Arguments;
+			this.ArgumentConversions = or.ArgumentConversions;
+			this.IsExtensionMethodInvocation = or.IsExtensionMethodInvocation;
+			this.IsExpandedForm = or.BestCandidateIsExpandedForm;
+			this.argumentToParameterMap = or.GetArgumentToParameterMap();
+		}
+		
+		static IType GetReturnType(OverloadResolution or, ITypeResolveContext context)
+		{
+			IType returnType;
+			if (or.BestCandidate.EntityType == EntityType.Constructor)
+				returnType = or.BestCandidate.DeclaringType;
+			else
+				returnType = or.BestCandidate.ReturnType.Resolve(context);
+			
+			var typeArguments = or.InferredTypeArguments;
+			if (typeArguments.Count > 0)
+				return returnType.AcceptVisitor(new MethodTypeParameterSubstitution(typeArguments));
+			else
+				return returnType;
+		}
+		
+		public override bool IsError {
+			get { return this.OverloadResolutionErrors != OverloadResolutionErrors.None; }
+		}
+		
+		/// <summary>
+		/// Gets an array that maps argument indices to parameter indices.
+		/// For arguments that could not be mapped to any parameter, the value will be -1.
+		/// 
+		/// parameterIndex = ArgumentToParameterMap[argumentIndex]
+		/// </summary>
+		public IList<int> GetArgumentToParameterMap()
+		{
+			return argumentToParameterMap;
+		}
+		
+		public new IParameterizedMember Member {
+			get { return (IParameterizedMember)base.Member; }
+		}
+	}
+}

ICSharpCode.NRefactory/CSharp/Resolver/MemberLookup.cs

@@ -162,8 +162,9 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		/// <summary>
 		/// Performs a member lookup.
 		/// </summary>
-		public ResolveResult Lookup(IType type, string name, IList<IType> typeArguments, bool isInvocation)
+		public ResolveResult Lookup(ResolveResult targetResolveResult, string name, IList<IType> typeArguments, bool isInvocation)
 		{
+			IType type = targetResolveResult.Type;
 			int typeArgumentCount = typeArguments.Count;
 			
 			List<IType> types = new List<IType>();
@@ -259,10 +260,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				return new UnknownMemberResolveResult(type, name, typeArguments);
 			IMember firstNonMethod = members.FirstOrDefault(m => !(m is IMethod));
 			if (members.Count == 1 && firstNonMethod != null)
-				return new MemberResolveResult(firstNonMethod, context);
+				return new MemberResolveResult(targetResolveResult, firstNonMethod, context);
 			if (firstNonMethod == null)
-				return new MethodGroupResolveResult(type, name, members.ConvertAll(m => (IMethod)m), typeArguments);
-			return new AmbiguousMemberResultResult(firstNonMethod, firstNonMethod.ReturnType.Resolve(context));
+				return new MethodGroupResolveResult(targetResolveResult, name, members.ConvertAll(m => (IMethod)m), typeArguments);
+			return new AmbiguousMemberResultResult(targetResolveResult, firstNonMethod, firstNonMethod.ReturnType.Resolve(context));
 		}
 
 		static bool IsNonInterfaceType(ITypeDefinition def)

ICSharpCode.NRefactory/CSharp/Resolver/MemberResolveResult.cs

@@ -14,25 +14,29 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		readonly IMember member;
 		readonly bool isConstant;
 		readonly object constantValue;
+		readonly ResolveResult targetResult;
 		
-		public MemberResolveResult(IMember member, IType returnType) : base(returnType)
+		public MemberResolveResult(ResolveResult targetResult, IMember member, IType returnType) : base(returnType)
 		{
 			if (member == null)
 				throw new ArgumentNullException("member");
+			this.targetResult = targetResult;
 			this.member = member;
 		}
 		
-		public MemberResolveResult(IMember member, IType returnType, object constantValue) : base(returnType)
+		public MemberResolveResult(ResolveResult targetResult, IMember member, IType returnType, object constantValue) : base(returnType)
 		{
 			if (member == null)
 				throw new ArgumentNullException("member");
+			this.targetResult = targetResult;
 			this.member = member;
 			this.isConstant = true;
 			this.constantValue = constantValue;
 		}
 		
-		public MemberResolveResult(IMember member, ITypeResolveContext context) : base(member.ReturnType.Resolve(context))
+		public MemberResolveResult(ResolveResult targetResult, IMember member, ITypeResolveContext context) : base(member.ReturnType.Resolve(context))
 		{
+			this.targetResult = targetResult;
 			this.member = member;
 			IField field = member as IField;
 			if (field != null) {

ICSharpCode.NRefactory/CSharp/Resolver/MethodGroupResolveResult.cs

@@ -17,26 +17,33 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 	{
 		readonly ReadOnlyCollection<IMethod> methods;
 		readonly ReadOnlyCollection<IType> typeArguments;
-		readonly IType targetType;
+		readonly ResolveResult targetResult;
 		readonly string methodName;
 		
-		public MethodGroupResolveResult(IType targetType, string methodName, IList<IMethod> methods, IList<IType> typeArguments) : base(SharedTypes.UnknownType)
+		public MethodGroupResolveResult(ResolveResult targetResult, string methodName, IList<IMethod> methods, IList<IType> typeArguments) : base(SharedTypes.UnknownType)
 		{
-			if (targetType == null)
-				throw new ArgumentNullException("targetType");
+			if (targetResult == null)
+				throw new ArgumentNullException("targetResult");
 			if (methods == null)
 				throw new ArgumentNullException("methods");
-			this.targetType = targetType;
+			this.targetResult = targetResult;
 			this.methodName = methodName;
 			this.methods = new ReadOnlyCollection<IMethod>(methods);
 			this.typeArguments = typeArguments != null ? new ReadOnlyCollection<IType>(typeArguments) : EmptyList<IType>.Instance;
 		}
 		
+		/// <summary>
+		/// Gets the resolve result for the target object.
+		/// </summary>
+		public ResolveResult TargetResult {
+			get { return targetResult; }
+		}
+		
 		/// <summary>
 		/// Gets the type of the reference to the target object.
 		/// </summary>
 		public IType TargetType {
-			get { return targetType; }
+			get { return targetResult.Type; }
 		}
 		
 		/// <summary>
@@ -81,7 +88,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				UsingScope oldUsingScope = resolver.UsingScope;
 				try {
 					resolver.UsingScope = usingScope;
-					extensionMethods = resolver.GetExtensionMethods(targetType, methodName, typeArguments.Count);
+					extensionMethods = resolver.GetExtensionMethods(this.TargetType, methodName, typeArguments.Count);
 				} finally {
 					resolver.UsingScope = oldUsingScope;
 					resolver = null;
@@ -121,6 +128,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					}
 					var extOr = new OverloadResolution(context, extArguments, extArgumentNames, typeArgumentArray);
 					extOr.AllowExpandingParams = allowExpandingParams;
+					extOr.IsExtensionMethodInvocation = true;
 					
 					foreach (var g in extensionMethods) {
 						foreach (var m in g) {

ICSharpCode.NRefactory/CSharp/Resolver/OverloadResolution.cs

@@ -114,12 +114,28 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		}
 		#endregion
 		
+		/// <summary>
+		/// Gets/Sets whether the methods are extension methods that are being called using extension method syntax.
+		/// </summary>
+		/// <remarks>
+		/// Setting this property to true restricts the possible conversions on the first argument to
+		/// implicit identity, reference, or boxing conversions.
+		/// </remarks>
+		public bool IsExtensionMethodInvocation { get; set; }
+		
 		/// <summary>
 		/// Gets/Sets whether expanding 'params' into individual elements is allowed.
 		/// The default value is true.
 		/// </summary>
 		public bool AllowExpandingParams { get; set; }
 		
+		/// <summary>
+		/// Gets the arguments for which this OverloadResolution instance was created.
+		/// </summary>
+		public IList<ResolveResult> Arguments {
+			get { return arguments; }
+		}
+		
 		#region AddCandidate
 		public OverloadResolutionErrors AddCandidate(IParameterizedMember member)
 		{
@@ -348,10 +364,17 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					if (candidate.Parameters[parameterIndex].IsOut || candidate.Parameters[parameterIndex].IsRef)
 						candidate.AddError(OverloadResolutionErrors.ParameterPassingModeMismatch);
 				}
-				Conversion c = conversions.ImplicitConversion(arguments[i], candidate.ParameterTypes[parameterIndex]);
+				IType parameterType = candidate.ParameterTypes[parameterIndex];
+				Conversion c = conversions.ImplicitConversion(arguments[i], parameterType);
 				candidate.ArgumentConversions[i] = c;
-				if (!c)
-					candidate.AddError(OverloadResolutionErrors.ArgumentTypeMismatch);
+				if (IsExtensionMethodInvocation && parameterIndex == 0) {
+					// First parameter to extension method must be an identity, reference or boxing conversion
+					if (!(c == Conversion.IdentityConversion || c == Conversion.ImplicitReferenceConversion || c == Conversion.BoxingConversion))
+						candidate.AddError(OverloadResolutionErrors.ArgumentTypeMismatch);
+				} else {
+					if (!c)
+						candidate.AddError(OverloadResolutionErrors.ArgumentTypeMismatch);
+				}
 			}
 		}
 		#endregion
@@ -576,5 +599,19 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					return new Conversion[arguments.Length];
 			}
 		}
+		
+		/// <summary>
+		/// Gets an array that maps argument indices to parameter indices.
+		/// For arguments that could not be mapped to any parameter, the value will be -1.
+		/// 
+		/// parameterIndex = GetArgumentToParameterMap()[argumentIndex]
+		/// </summary>
+		public IList<int> GetArgumentToParameterMap()
+		{
+			if (bestCandidate != null)
+				return bestCandidate.ArgumentToParameterMap;
+			else
+				return null;
+		}
 	}
 }

ICSharpCode.NRefactory/CSharp/Resolver/ResolveVisitor.cs

@@ -332,7 +332,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			if (resolverEnabled) {
 				if (variableInitializer.Parent is FieldDeclaration) {
 					if (resolver.CurrentMember != null)
-						return new MemberResolveResult(resolver.CurrentMember, resolver.CurrentMember.ReturnType.Resolve(resolver.Context));
+						return new MemberResolveResult(null, resolver.CurrentMember, resolver.CurrentMember.ReturnType.Resolve(resolver.Context));
 				} else {
 					string identifier = variableInitializer.Name;
 					foreach (IVariable v in resolver.LocalVariables) {
@@ -353,7 +353,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			ScanChildren(fixedVariableInitializer);
 			if (resolverEnabled) {
 				if (resolver.CurrentMember != null)
-					return new MemberResolveResult(resolver.CurrentMember, resolver.CurrentMember.ReturnType.Resolve(resolver.Context));
+					return new MemberResolveResult(null, resolver.CurrentMember, resolver.CurrentMember.ReturnType.Resolve(resolver.Context));
 				else
 					return errorResult;
 			} else {
@@ -371,7 +371,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				ScanChildren(member);
 				
 				if (resolverEnabled && resolver.CurrentMember != null)
-					return new MemberResolveResult(resolver.CurrentMember, resolver.Context);
+					return new MemberResolveResult(null, resolver.CurrentMember, resolver.Context);
 				else
 					return errorResult;
 			} finally {
@@ -418,7 +418,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					}
 				}
 				if (resolverEnabled && resolver.CurrentMember != null)
-					return new MemberResolveResult(resolver.CurrentMember, resolver.Context);
+					return new MemberResolveResult(null, resolver.CurrentMember, resolver.Context);
 				else
 					return errorResult;
 			} finally {
@@ -453,7 +453,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				}
 				
 				if (resolverEnabled && resolver.CurrentMember != null)
-					return new MemberResolveResult(resolver.CurrentMember, resolver.Context);
+					return new MemberResolveResult(null, resolver.CurrentMember, resolver.Context);
 				else
 					return errorResult;
 			} finally {
@@ -522,7 +522,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				ScanChildren(enumMemberDeclaration);
 				
 				if (resolverEnabled && resolver.CurrentMember != null)
-					return new MemberResolveResult(resolver.CurrentMember, resolver.Context);
+					return new MemberResolveResult(null, resolver.CurrentMember, resolver.Context);
 				else
 					return errorResult;
 			} finally {

ICSharpCode.NRefactory/ICSharpCode.NRefactory.csproj

@@ -104,6 +104,7 @@
     <Compile Include="CSharp\Refactoring\TypeSystemAstBuilder.cs" />
     <Compile Include="CSharp\Resolver\CSharpAttribute.cs" />
     <Compile Include="CSharp\Resolver\ConstantValues.cs" />
+    <Compile Include="CSharp\Resolver\InvocationResolveResult.cs" />
     <Compile Include="CSharp\Resolver\LambdaResolveResult.cs" />
     <Compile Include="CSharp\Resolver\MapTypeIntoNewContext.cs" />
     <Compile Include="CSharp\Resolver\SimpleNameLookupMode.cs" />