CSharpAstResolver: don't return the same ResolveResult for two different nodes.

(make clones when using caches)
Closes icsharpcode/NRefactory#46.

ICSharpCode.NRefactory.CSharp/Resolver/CSharpResolver.cs

@@ -41,8 +41,6 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 	public class CSharpResolver
 	{
 		static readonly ResolveResult ErrorResult = ErrorResolveResult.UnknownError;
-		static readonly ResolveResult DynamicResult = new ResolveResult(SpecialType.Dynamic);
-		static readonly ResolveResult NullResult = new ResolveResult(SpecialType.NullType);
 		
 		readonly ICompilation compilation;
 		internal readonly CSharpConversions conversions;
@@ -1381,7 +1379,9 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 							foundInCache = cache.TryGetValue(identifier, out r);
 					}
 				}
-				if (!foundInCache) {
+				if (foundInCache) {
+					r = (r != null ? r.ShallowClone() : null);
+				} else {
 					r = LookInCurrentType(identifier, typeArguments, lookupMode, parameterizeResultType);
 					if (cache != null) {
 						// also cache missing members (r==null)
@@ -1398,9 +1398,11 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				r = LookInUsingScopeNamespace(null, compilation.RootNamespace, identifier, typeArguments, parameterizeResultType);
 			} else {
 				if (k == 0 && lookupMode != NameLookupMode.TypeInUsingDeclaration) {
-					if (!context.CurrentUsingScope.ResolveCache.TryGetValue(identifier, out r)) {
+					if (context.CurrentUsingScope.ResolveCache.TryGetValue(identifier, out r)) {
+						r = (r != null ? r.ShallowClone() : null);
+					} else {
 						r = LookInCurrentUsingScope(identifier, typeArguments, false, false);
-						r = context.CurrentUsingScope.ResolveCache.GetOrAdd(identifier, r);
+						context.CurrentUsingScope.ResolveCache.TryAdd(identifier, r);
 					}
 				} else {
 					r = LookInCurrentUsingScope(identifier, typeArguments, lookupMode == NameLookupMode.TypeInUsingDeclaration, parameterizeResultType);
@@ -1477,7 +1479,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					if (!(isInUsingDeclaration && u == currentUsingScope)) {
 						foreach (var pair in u.UsingAliases) {
 							if (pair.Key == identifier) {
-								return pair.Value;
+								return pair.Value.ShallowClone();
 							}
 						}
 					}
@@ -1589,7 +1591,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			}
 			
 			if (target.Type.Kind == TypeKind.Dynamic)
-				return DynamicResult;
+				return new ResolveResult(SpecialType.Dynamic);
 			
 			MemberLookup lookup = CreateMemberLookup(lookupMode);
 			ResolveResult result;
@@ -1887,7 +1889,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			// C# 4.0 spec: §7.6.5
 			
 			if (target.Type.Kind == TypeKind.Dynamic)
-				return DynamicResult;
+				return new ResolveResult(SpecialType.Dynamic);
 			
 			MethodGroupResolveResult mgrr = target as MethodGroupResolveResult;
 			if (mgrr != null) {
@@ -2297,7 +2299,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		public ResolveResult ResolvePrimitive(object value)
 		{
 			if (value == null) {
-				return NullResult;
+				return new ResolveResult(SpecialType.NullType);
 			} else {
 				TypeCode typeCode = Type.GetTypeCode(value.GetType());
 				IType type = compilation.FindType(typeCode);

ICSharpCode.NRefactory.CSharp/Resolver/ResolveVisitor.cs

@@ -59,7 +59,6 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		// The ResolveVisitor is also responsible for handling lambda expressions.
 		
 		static readonly ResolveResult errorResult = ErrorResolveResult.UnknownError;
-		readonly ResolveResult voidResult;
 		
 		CSharpResolver resolver;
 		/// <summary>Resolve result of the current LINQ query.</summary>
@@ -112,13 +111,18 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			this.resolver = resolver;
 			this.parsedFile = parsedFile;
 			this.navigator = skipAllNavigator;
-			this.voidResult = new ResolveResult(resolver.Compilation.FindType(KnownTypeCode.Void));
 		}
 		
 		internal void SetNavigator(IResolveVisitorNavigator navigator)
 		{
 			this.navigator = navigator ?? skipAllNavigator;
 		}
+		
+		ResolveResult voidResult {
+			get {
+				return new ResolveResult(resolver.Compilation.FindType(KnownTypeCode.Void));
+			}
+		}
 		#endregion
 		
 		#region ResetContext
@@ -1594,7 +1598,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		ResolveResult IAstVisitor<ResolveResult>.VisitTypeReferenceExpression(TypeReferenceExpression typeReferenceExpression)
 		{
 			if (resolverEnabled) {
-				return Resolve(typeReferenceExpression.Type);
+				return Resolve(typeReferenceExpression.Type).ShallowClone();
 			} else {
 				Scan(typeReferenceExpression.Type);
 				return null;
@@ -2420,6 +2424,13 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			internal abstract AstNode BodyExpression { get; }
 			
 			internal abstract void EnforceMerge(ResolveVisitor parentVisitor);
+			
+			public override ResolveResult ShallowClone()
+			{
+				if (IsUndecided)
+					throw new NotSupportedException();
+				return base.ShallowClone();
+			}
 		}
 		
 		void MergeUndecidedLambdas()
@@ -3261,7 +3272,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				foreach (var clause in queryExpression.Clauses) {
 					currentQueryResult = Resolve(clause);
 				}
-				return currentQueryResult;
+				return WrapResult(currentQueryResult);
 			} finally {
 				currentQueryResult = oldQueryResult;
 				cancellationToken = oldCancellationToken;

ICSharpCode.NRefactory.ConsistencyCheck/ResolverTest.cs

@@ -55,6 +55,7 @@ namespace ICSharpCode.NRefactory.ConsistencyCheck
 			}
 			
 			Dictionary<AstNode, ResolveResult> resolvedNodes = new Dictionary<AstNode, ResolveResult>();
+			HashSet<ResolveResult> resolveResults = new HashSet<ResolveResult>();
 			HashSet<AstNode> nodesWithConversions = new HashSet<AstNode>();
 			
 			public ResolveVisitorNavigationMode Scan(AstNode node)
@@ -69,6 +70,9 @@ namespace ICSharpCode.NRefactory.ConsistencyCheck
 				resolvedNodes.Add(node, result);
 				if (CSharpAstResolver.IsUnresolvableNode(node))
 					throw new InvalidOperationException("Resolved unresolvable node");
+				if (!ParenthesizedExpression.ActsAsParenthesizedExpression(node))
+					if (!resolveResults.Add(result))
+						throw new InvalidOperationException("Duplicate resolve result");
 				
 				if (result.IsError && !allowErrors) {
 					Console.WriteLine("Compiler error at " + fileName + ":" + node.StartLocation + ": " + result);

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

@@ -103,8 +103,8 @@ class TestClass {
 	}
 }
 ";
-			var rr = Resolve<CSharpInvocationResolveResult>(program);
-			Assert.AreEqual("System.Linq.Enumerable.Select", rr.Member.FullName);
+			var rr = Resolve<ConversionResolveResult>(program);
+			Assert.IsTrue(rr.Conversion.IsIdentityConversion);
 			Assert.AreEqual("System.Collections.Generic.IEnumerable", rr.Type.FullName);
 			Assert.AreEqual("System.Int32", ((ParameterizedType)rr.Type).TypeArguments[0].FullName);
 		}
@@ -114,7 +114,7 @@ class TestClass {
 		{
 			string program = @"using System;
 class TestClass { static void M() {
-	$(from a in new XYZ() select a.ToUpper())$.ToString();
+	(from a in new XYZ() $select a.ToUpper()$).ToString();
 }}
 class XYZ {
 	public int Select<U>(Func<string, U> f) { return 42; }

ICSharpCode.NRefactory/Semantics/MemberResolveResult.cs

@@ -75,6 +75,16 @@ namespace ICSharpCode.NRefactory.Semantics
 			this.constantValue = constantValue;
 		}
 		
+		public MemberResolveResult(ResolveResult targetResult, IMember member, IType returnType, bool isConstant, object constantValue, bool isVirtualCall)
+			: base(returnType)
+		{
+			this.targetResult = targetResult;
+			this.member = member;
+			this.isConstant = isConstant;
+			this.constantValue = constantValue;
+			this.isVirtualCall = isVirtualCall;
+		}
+		
 		public ResolveResult TargetResult {
 			get { return targetResult; }
 		}

ICSharpCode.NRefactory/Semantics/ResolveResult.cs

@@ -70,5 +70,10 @@ namespace ICSharpCode.NRefactory.Semantics
 		{
 			return DomRegion.Empty;
 		}
+		
+		public virtual ResolveResult ShallowClone()
+		{
+			return (ResolveResult)MemberwiseClone();
+		}
 	}
 }

ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultMemberReference.cs

@@ -63,7 +63,9 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			IType type = typeReference.Resolve(context);
 			IEnumerable<IMember> members;
 			if (entityType == EntityType.Accessor) {
-				members = type.GetAccessors(m => m.Name == name && !m.IsExplicitInterfaceImplementation);
+				members = type.GetAccessors(
+					m => m.Name == name && !m.IsExplicitInterfaceImplementation,
+					GetMemberOptions.IgnoreInheritedMembers);
 			} else if (entityType == EntityType.Method) {
 				members = type.GetMethods(
 					m => m.Name == name && m.EntityType == EntityType.Method