Fixed bug in GetCurrentParameterIndex + added unit tests for this

function.

ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngineBase.cs

@@ -155,14 +155,11 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 		public int GetCurrentParameterIndex (int triggerOffset, int endOffset, out List<string> usedNamedParameters)
 		{
 			usedNamedParameters =new List<string> ();
-			char lastChar = document.GetCharAt (endOffset - 1);
-			if (lastChar == '(' || lastChar == '<') { 
-				return 0;
-			}
 			var parameter = new Stack<int> ();
 			var bracketStack = new Stack<Stack<int>> ();
 			bool inSingleComment = false, inString = false, inVerbatimString = false, inChar = false, inMultiLineComment = false;
 			var word = new StringBuilder ();
+			bool foundCharAfterOpenBracket = false;
 			for (int i = triggerOffset; i < endOffset; i++) {
 				char ch = document.GetCharAt (i);
 				char nextCh = i + 1 < document.TextLength ? document.GetCharAt (i + 1) : '\0';
@@ -176,6 +173,8 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 				} else {
 					word.Length = 0;
 				}
+				if (!char.IsWhiteSpace(ch) && parameter.Count > 0)
+					foundCharAfterOpenBracket = true;
 				switch (ch) {
 					case '{':
 						if (inString || inChar || inVerbatimString || inSingleComment || inMultiLineComment) {
@@ -303,10 +302,11 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 						break;
 				}
 			}
-			if (parameter.Count == 0 || bracketStack.Count > 0) {
+			if (parameter.Count != 1 || bracketStack.Count > 0) {
 				return -1;
 			}
-
+			if (!foundCharAfterOpenBracket)
+				return 0;
 			return parameter.Pop() + 1;
 		}
 

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

@@ -0,0 +1,100 @@
+//
+// GetCurrentParameterIndexTests.cs
+//
+// Author:
+//       Mike Krüger <mkrueger@xamarin.com>
+//
+// Copyright (c) 2013 Xamarin Inc. (http://xamarin.com)
+//
+// 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 NUnit.Framework;
+using ICSharpCode.NRefactory.CSharp.Completion;
+using ICSharpCode.NRefactory.Editor;
+using ICSharpCode.NRefactory.CSharp.TypeSystem;
+using System.Text;
+
+namespace ICSharpCode.NRefactory.CSharp.CodeCompletion
+{
+	[TestFixture]
+	public class GetCurrentParameterIndexTests
+	{
+		static int GetIndex(string text)
+		{
+			var editorText = new StringBuilder();
+			int trigger = 0, end = 0;
+			for (int i = 0; i < text.Length; i++) {
+				if (text[i] == '@') {
+					trigger = editorText.Length;
+					continue;
+				}
+				if (text[i] == '$') {
+					end = editorText.Length;
+					continue;
+				}
+				editorText.Append(text [i]);
+			}
+
+			var doc = new ReadOnlyDocument(editorText.ToString ());
+			var pctx = new CSharpProjectContent();
+			var rctx = new CSharpTypeResolveContext(pctx.CreateCompilation().MainAssembly);
+			var ctxProvider = new DefaultCompletionContextProvider(doc, new CSharpUnresolvedFile("a.cs"));
+			var engine = new CSharpParameterCompletionEngine(doc, ctxProvider, new ParameterCompletionTests.TestFactory(pctx), pctx, rctx);
+
+			return engine.GetCurrentParameterIndex(trigger, end);
+		}
+
+		[Test]
+		public void TestFirstParameterStart ()
+		{
+			var index = GetIndex("@Test($");
+			Assert.AreEqual(0, index);
+		}
+
+		[Test]
+		public void TestFirstParameter ()
+		{
+			var index = GetIndex("@Test(foo$");
+			Assert.AreEqual(1, index);
+		}
+
+		[Test]
+		public void TestSecondParameter ()
+		{
+			var index = GetIndex("@Test(foo, $");
+			Assert.AreEqual(2, index);
+		}
+
+		
+		[Test]
+		public void TestAfterMethod ()
+		{
+			var index = GetIndex("@Test(foo) $");
+			Assert.AreEqual(-1, index);
+		}
+
+		[Test]
+		public void TestJaggedMethod ()
+		{
+			var index = GetIndex("@Foo(Test($");
+			Assert.AreEqual(-1, index);
+		}
+	}
+}
+

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

@@ -42,7 +42,7 @@ namespace ICSharpCode.NRefactory.CSharp.CodeCompletion
 	[TestFixture()]
 	public class ParameterCompletionTests : TestBase
 	{
-		class TestFactory : IParameterCompletionDataFactory
+		internal class TestFactory : IParameterCompletionDataFactory
 		{
 			IProjectContent ctx;
 			
@@ -295,7 +295,7 @@ namespace ICSharpCode.NRefactory.CSharp.CodeCompletion
 				cursorPosition = endPos - 1; 
 			}
 			var doc = new ReadOnlyDocument(editorText);
-			
+
 			IProjectContent pctx = new CSharpProjectContent();
 			pctx = pctx.AddAssemblyReferences(new [] { CecilLoaderTests.Mscorlib, CecilLoaderTests.SystemCore });
 			

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

@@ -390,6 +390,7 @@
     <Compile Include="IndentationTests\IndentationTests.cs" />
     <Compile Include="CSharp\CodeCompletion\ImportCompletionTests.cs" />
     <Compile Include="CSharp\CodeActions\CreateEnumValueTests.cs" />
+    <Compile Include="CSharp\CodeCompletion\GetCurrentParameterIndexTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\cecil\Mono.Cecil.csproj">