[Completion] Added a case to prevent recursive constructor calls:

'public A() : this()'.

ICSharpCode.NRefactory.CSharp/Completion/CSharpParameterCompletionEngine.cs

@@ -152,7 +152,7 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 					if (invoke.Node is ConstructorInitializer) {
 						var init = (ConstructorInitializer)invoke.Node;
 						if (init.ConstructorInitializerType == ConstructorInitializerType.This) {
-							return factory.CreateConstructorProvider(document.GetOffset(invoke.Node.StartLocation), ctx.CurrentTypeDefinition);
+							return factory.CreateConstructorProvider(document.GetOffset(invoke.Node.StartLocation), ctx.CurrentTypeDefinition, init);
 						} else {
 							var baseType = ctx.CurrentTypeDefinition.DirectBaseTypes.FirstOrDefault(bt => bt.Kind != TypeKind.Interface);
 							if (baseType == null) {

ICSharpCode.NRefactory.CSharp/Completion/IParameterCompletionDataFactory.cs

@@ -35,6 +35,11 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 	{
 		IParameterDataProvider CreateConstructorProvider (int startOffset, IType type);
 
+		/// <summary>
+		/// Creates a constructor provider skipping the parent of thisInitializer.
+		/// </summary>
+		IParameterDataProvider CreateConstructorProvider (int startOffset, IType type, AstNode thisInitializer);
+
 		IParameterDataProvider CreateMethodDataProvider (int startOffset, IEnumerable<IMethod> methods);
 
 		IParameterDataProvider CreateDelegateDataProvider (int startOffset, IType type);

ICSharpCode.NRefactory.Tests/CSharp/CodeCompletion/ParameterCompletionTests.cs

@@ -220,6 +220,14 @@ namespace ICSharpCode.NRefactory.CSharp.CodeCompletion
 				};
 			}
 
+			public IParameterDataProvider CreateConstructorProvider(int startOffset, ICSharpCode.NRefactory.TypeSystem.IType type, AstNode skipNode)
+			{
+				Assert.IsTrue(type.Kind != TypeKind.Unknown);
+				return new Provider () {
+					Data = type.GetConstructors (m => m.Accessibility == Accessibility.Public)
+				};
+			}
+
 			public IParameterDataProvider CreateMethodDataProvider (int startOffset, IEnumerable<IMethod> methods)
 			{
 				return new Provider () {