Merge NRefactory changes from SharpDevelop to NRefactory repository.

* Fix NRE in TypeGuessing after `yield return new`
* Add message text to CS0618UsageOfObsoleteMemberIssue
* Fix IndexOutOfRangeException in AddOptionalParameterToInvocationAction
* Fix icsharpcode/SharpDevelop#580: EventHandler names suggested by code completion should include the variable name/expression.
* Fix icsharpcode/SharpDevelop#574: Wrong error highlighting with interface implementation

3 files changed, 57 insertions, 7 deletions

diff --git a/ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngine.cs b/ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngine.cs
index e016692d..28c9ea02 100644
--- a/ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngine.cs
+++ b/ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngine.cs
@@ -886,7 +886,7 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 									string parameterDefinition = AddDelegateHandlers(
 										wrapper,
 										delegateType,
-										optDelegateName: GuessEventHandlerMethodName(curTokenIndex)
+										optDelegateName: GuessEventHandlerMethodName(curTokenIndex, (currentType == null) ? null : currentType.Name)
 									);
 								}
 
@@ -2589,10 +2589,49 @@ namespace ICSharpCode.NRefactory.CSharp.Completion
 			}
 		}
 
-		public string GuessEventHandlerMethodName(int tokenIndex)
+		public string GuessEventHandlerMethodName(int tokenIndex, string surroundingTypeName)
 		{
+			var names = new List<string>();
+			
+			string eventName = GetPreviousToken(ref tokenIndex, false);
 			string result = GetPreviousToken(ref tokenIndex, false);
-			return "Handle" + result;
+			if (result != ".") {
+				if (surroundingTypeName == null) {
+					eventName = "Handle" + eventName;
+				} else {
+					names.Add(surroundingTypeName);
+				}
+			}
+			while (result == ".") {
+				result = GetPreviousToken(ref tokenIndex, false);
+				if (result == "this") {
+					if (names.Count == 0) {
+						if (surroundingTypeName == null) {
+							eventName = "Handle" + eventName;
+						} else {
+							names.Add(surroundingTypeName);
+						}
+					}
+				} else if (result != null) {
+					string trimmedName = result.Trim();
+					if (trimmedName.Length == 0) {
+						break;
+					}
+					names.Insert(0, trimmedName);
+				}
+				result = GetPreviousToken(ref tokenIndex, false);
+			}
+			if (!string.IsNullOrEmpty(eventName)) {
+				names.Add(eventName);
+			}
+			result = String.Join("_", names.ToArray());
+			foreach (char ch in result) {
+				if (!char.IsLetterOrDigit(ch) && ch != '_') {
+					result = "";
+					break;
+				}
+			}
+			return result;
 		}
 
 		bool MatchDelegate(IType delegateType, IMethod method)
diff --git a/ICSharpCode.NRefactory.CSharp/Refactoring/Script.cs b/ICSharpCode.NRefactory.CSharp/Refactoring/Script.cs
index a82006a7..a69b5c92 100644
--- a/ICSharpCode.NRefactory.CSharp/Refactoring/Script.cs
+++ b/ICSharpCode.NRefactory.CSharp/Refactoring/Script.cs
@@ -624,7 +624,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 		}
 	}
 
-	static class ExtMethods
+	public static class ExtMethods
 	{
 		public static void ContinueScript (this Task task, Action act)
 		{
diff --git a/ICSharpCode.NRefactory.CSharp/Refactoring/TypeGuessing.cs b/ICSharpCode.NRefactory.CSharp/Refactoring/TypeGuessing.cs
index 3a7e886b..dd04185b 100644
--- a/ICSharpCode.NRefactory.CSharp/Refactoring/TypeGuessing.cs
+++ b/ICSharpCode.NRefactory.CSharp/Refactoring/TypeGuessing.cs
@@ -259,9 +259,20 @@ namespace ICSharpCode.NRefactory.CSharp
 			}
 
 			if (expr.Parent is YieldReturnStatement) {
-				var state = resolver.GetResolverStateBefore(expr);
-				if (state != null && (state.CurrentMember.ReturnType is ParameterizedType)) {
-					var pt = (ParameterizedType)state.CurrentMember.ReturnType;
+				ParameterizedType pt = null;
+				var parent = expr.Ancestors.FirstOrDefault(n => n is EntityDeclaration || n is AnonymousMethodExpression|| n is LambdaExpression);
+				if (parent != null) {
+					var rr = resolver.Resolve(parent);
+					if (!rr.IsError)
+						pt = rr.Type as ParameterizedType;
+				}
+				var e = parent as EntityDeclaration;
+				if (e != null) {
+					var rt = resolver.Resolve(e.ReturnType);
+					if (!rt.IsError)
+						pt = rt.Type as ParameterizedType;
+				}
+				if (pt != null) {
 					if (pt.FullName == "System.Collections.Generic.IEnumerable") {
 						return new [] { pt.TypeArguments.First() };
 					}