Prevent creating ConstructedReturnTypes that cause infinite recursion.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/2.0@1390 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/BackendBindings/Boo/BooBinding/Project/Src/CodeCompletion/InferredReturnType.cs

@@ -43,7 +43,7 @@ namespace Grunwald.BooBinding.CodeCompletion
 			get {
 				// clear up references to method/expression after the type has been resolved
 				if (block != null) {
-					GetReturnTypeVisitor v = new GetReturnTypeVisitor(context);
+					GetReturnTypeVisitor v = new GetReturnTypeVisitor(this);
 					Block b = block;
 					block = null; // reset block before calling Visit to prevent StackOverflow
 					v.Visit(b);
@@ -70,9 +70,11 @@ namespace Grunwald.BooBinding.CodeCompletion
 		class GetReturnTypeVisitor : DepthFirstVisitor
 		{
 			IClass context;
-			public GetReturnTypeVisitor(IClass context)
+			InferredReturnType parentReturnType;
+			public GetReturnTypeVisitor(InferredReturnType parentReturnType)
 			{
-				this.context = context;
+				this.context = parentReturnType.context;
+				this.parentReturnType = parentReturnType;
 			}
 			
 			public IReturnType result;
@@ -99,7 +101,18 @@ namespace Grunwald.BooBinding.CodeCompletion
 			{
 				noReturnStatement = false;
 				IClass enumerable = ProjectContentRegistry.Mscorlib.GetClass("System.Collections.Generic.IEnumerable", 1);
-				result = new ConstructedReturnType(enumerable.DefaultReturnType, new IReturnType[] { new InferredReturnType(node.Expression, context) });
+				
+				// Prevent creating an infinite number of InferredReturnTypes in inferring cycles
+				parentReturnType.expression = new NullLiteralExpression();
+				IReturnType returnType = new BooResolver().GetTypeOfExpression(node.Expression, context);
+				returnType.GetUnderlyingClass(); // force to infer type
+				if (parentReturnType.expression == null) {
+					// inferrence cycle with parentReturnType
+					returnType = new GetClassReturnType(context.ProjectContent, "?", 0);
+				}
+				parentReturnType.expression = null;
+				
+				result = new ConstructedReturnType(enumerable.DefaultReturnType, new IReturnType[] { returnType });
 			}
 			
 			public override void OnCallableBlockExpression(CallableBlockExpression node)

src/AddIns/BackendBindings/Boo/BooBinding/Test/ResolverTests.cs

@@ -254,6 +254,23 @@ namespace Grunwald.BooBinding.Tests
 			LocalResolveResult rr2 = Resolve<LocalResolveResult>(prog, "mybool", "/*mark*/");
 			Assert.AreEqual("System.Boolean", rr2.ResolvedType.FullyQualifiedName);
 		}
+		
+		[Test]
+		public void InfiniteRecursionGenerator()
+		{
+			string prog =
+				"class Test:\n" +
+				"\t_testList = []\n" +
+				"\tTestProperty:\n" +
+				"\t\tget:\n" +
+				"\t\t\tfor testobj as Test in _testList:\n" +
+				"\t\t\t\tyield testobj.TestProperty /*mark*/\n";
+			MemberResolveResult rr = Resolve<MemberResolveResult>(prog, "testobj.TestProperty", "/*mark*/");
+			Assert.AreEqual("Test.TestProperty", rr.ResolvedMember.FullyQualifiedName);
+			Assert.AreEqual("System.Collections.Generic.IEnumerable", rr.ResolvedType.FullyQualifiedName);
+			// prevent creating self-referring ConstructedReturnType
+			Assert.AreEqual("?", rr.ResolvedType.TypeArguments[0].FullyQualifiedName);
+		}
 		#endregion
 		
 		#region Nested Classes