Fix ArgumentOutOfRangeException when searching for references on array indexer.

src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/LanguageProperties.cs

@@ -532,11 +532,10 @@ namespace ICSharpCode.SharpDevelop.Dom
 			public override TextFinderMatch Find(string inputText, int startPosition)
 			{
 				int pos = inputText.IndexOf(searchText, startPosition);
-				if (pos >= 0) {
+				if (pos > 0) {
 					return new TextFinderMatch(pos, searchText.Length, pos - 1);
-				} else {
-					return TextFinderMatch.Empty;
 				}
+				return TextFinderMatch.Empty;
 			}
 		}
 		#endregion

src/Main/ICSharpCode.SharpDevelop.Dom/Tests/ICSharpCode.SharpDevelop.Dom.Tests/ICSharpCode.SharpDevelop.Dom.Tests.csproj

@@ -52,8 +52,10 @@
     <Compile Include="CodeSnippetConverterTests.cs" />
     <Compile Include="CSharpAmbienceTests.cs" />
     <Compile Include="ImplementInterfaceTests.cs" />
+    <Compile Include="IndexBeforeTextFinderTests.cs" />
     <Compile Include="NRefactoryAstConverterTests.cs" />
     <Compile Include="NRefactoryRefactoringProviderTests.cs" />
+    <Compile Include="NUnitHelpers\IndexBeforeTextFinderHelper.cs" />
     <Compile Include="NUnitHelpers\SyntaxHelpers.cs" />
     <Compile Include="NUnitHelpers\Constraints.cs" />
     <Compile Include="ProjectContentClassManagementTest.cs" />

src/Main/ICSharpCode.SharpDevelop.Dom/Tests/ICSharpCode.SharpDevelop.Dom.Tests/IndexBeforeTextFinderTests.cs

@@ -0,0 +1,70 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using ICSharpCode.SharpDevelop.Dom;
+using ICSharpCode.SharpDevelop.Dom.Refactoring;
+using ICSharpCode.SharpDevelop.Dom.Tests.NUnitHelpers;
+using NUnit.Framework;
+
+namespace ICSharpCode.SharpDevelop.Dom.Tests
+{
+	[TestFixture]
+	public class IndexBeforeTextFinderTests
+	{
+		TextFinder textFinder;
+		IndexBeforeTextFinderHelper helper;
+		
+		void CreateIndexBeforeTextFinderWithSearchTextOf(string searchText)
+		{
+			helper = new IndexBeforeTextFinderHelper();
+			textFinder = helper.CreateIndexBeforeTextFinder(searchText);
+		}
+		
+		void AssertTextFindMatchesAreEqual(TextFinderMatch expectedMatch, TextFinderMatch actualMatch)
+		{
+			string expectedMatchAsString = GetTextFinderMatchAsString(expectedMatch);
+			string actualMatchAsString = GetTextFinderMatchAsString(actualMatch);
+			Assert.AreEqual(expectedMatchAsString, actualMatchAsString);
+		}
+		
+		string GetTextFinderMatchAsString(TextFinderMatch match)
+		{
+			return String.Format(
+				"Position: {0}, Length: {1}, ResolvePosition: {2}",
+				match.Position,
+				match.Length,
+				match.ResolvePosition);
+		}
+
+		[Test]
+		public void Find_SearchingForSquareBracketCharacterAndInputTextHasNoSquareBracketCharacter_ReturnsEmptyTextFinderMatch()
+		{
+			CreateIndexBeforeTextFinderWithSearchTextOf("[");
+			TextFinderMatch match = textFinder.Find("abc", 0);
+			
+			AssertTextFindMatchesAreEqual(TextFinderMatch.Empty, match);
+		}
+		
+		[Test]
+		public void Find_SearchingForSquareBracketCharacterAndInputTextHasSquareBracketAtPositionOne_ReturnsTextFinderMatchForPositionOne()
+		{
+			CreateIndexBeforeTextFinderWithSearchTextOf("[");
+			TextFinderMatch match = textFinder.Find("a[0]", 0);
+			
+			TextFinderMatch expectedMatch = 
+				new TextFinderMatch(position: 1, length: 1, resolvePosition: 0);
+			
+			AssertTextFindMatchesAreEqual(expectedMatch, match);
+		}
+		
+		[Test]
+		public void Find_SearchingForSquareBracketCharacterAndInputTextHasSquareBracketCharacterAtPositionZero_ReturnsEmptyTextFinderMatch()
+		{
+			CreateIndexBeforeTextFinderWithSearchTextOf("[");
+			TextFinderMatch match = textFinder.Find("[assembly: AssemblyCulture(\"\")]", 0);
+			
+			AssertTextFindMatchesAreEqual(TextFinderMatch.Empty, match);
+		}
+	}
+}

src/Main/ICSharpCode.SharpDevelop.Dom/Tests/ICSharpCode.SharpDevelop.Dom.Tests/NUnitHelpers/IndexBeforeTextFinderHelper.cs

@@ -0,0 +1,21 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using ICSharpCode.SharpDevelop.Dom.Refactoring;
+
+namespace ICSharpCode.SharpDevelop.Dom.Tests.NUnitHelpers
+{
+	public class IndexBeforeTextFinderHelper : LanguageProperties
+	{
+		public IndexBeforeTextFinderHelper()
+			: base(StringComparer.Ordinal)
+		{
+		}
+		
+		public TextFinder CreateIndexBeforeTextFinder(string searchText)
+		{
+			return new IndexBeforeTextFinder(searchText);
+		}
+	}
+}