[CodeActions] ConvertAsToCastAction: fixed some parentheses issues

ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/ConvertAsToCastAction.cs

@@ -32,13 +32,27 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 	[ContextAction("Convert 'as' to cast.", Description = "Convert 'as' to cast.")]
 	public class ConvertAsToCastAction : SpecializedCodeAction <AsExpression>
 	{
-
+		static InsertParenthesesVisitor insertParentheses = new InsertParenthesesVisitor ();
 		protected override CodeAction GetAction (RefactoringContext context, AsExpression node)
 		{
 			if (!node.AsToken.Contains (context.Location))
 				return null;
-			return new CodeAction (context.TranslateString ("Convert 'as' to cast"), 
-				script => script.Replace (node, new CastExpression (node.Type.Clone (), node.Expression.Clone ())));
+			return new CodeAction (context.TranslateString ("Convert 'as' to cast"),  script => {
+				var castExpr = new CastExpression (node.Type.Clone (), node.Expression.Clone ());
+				var parenthesizedExpr = node.Parent as ParenthesizedExpression;
+				if (parenthesizedExpr != null && parenthesizedExpr.Parent is Expression) {
+					// clone parent expression and replace the ParenthesizedExpression with castExpr to remove
+					// parentheses, then insert parentheses if necessary
+					var parentExpr = (Expression)parenthesizedExpr.Parent.Clone ();
+					parentExpr.GetNodeContaining (parenthesizedExpr.StartLocation, parenthesizedExpr.EndLocation)
+						.ReplaceWith (castExpr);
+					parentExpr.AcceptVisitor (insertParentheses);
+					script.Replace (parenthesizedExpr.Parent, parentExpr);
+				} else {
+					castExpr.AcceptVisitor (insertParentheses);
+					script.Replace (node, castExpr);
+				}
+			});
 		}
 	}
 }

ICSharpCode.NRefactory.Tests/CSharp/CodeActions/ConvertAsToCastTests.cs

@@ -34,7 +34,7 @@ namespace ICSharpCode.NRefactory.CSharp.CodeActions
 	public class ConvertAsToCastTests : ContextActionTestBase
 	{
 		[Test]
-		public void Test()
+		public void Test ()
 		{
 			Test<ConvertAsToCastAction> (@"
 using System;
@@ -54,5 +54,45 @@ class TestClass
 	}
 }");
 		}
+
+		[Test]
+		public void TestRemoveParentheses ()
+		{
+			string input = @"
+class TestClass {
+	void TestMethod (object o)
+	{
+		var b = 1 + (o $as TestClass);
+	}
+}";
+			string output = @"
+class TestClass {
+	void TestMethod (object o)
+	{
+		var b = 1 + (TestClass)o;
+	}
+}";
+			Test<ConvertAsToCastAction> (input, output);
+		}
+
+		[Test]
+		public void TestInsertParentheses ()
+		{
+			string input = @"
+class TestClass {
+	void TestMethod (object o)
+	{
+		var b = 1 + o $as TestClass;
+	}
+}";
+			string output = @"
+class TestClass {
+	void TestMethod (object o)
+	{
+		var b = (TestClass)(1 + o);
+	}
+}";
+			Test<ConvertAsToCastAction> (input, output);
+		}
 	}
 }