VB -> C#: Parenthesize if nested - fixes #178

I haven't checked the operator precedence, let's err on the side of caution - can always refine later but it's tricky since we don't know the parent won't change precendence from VB too at this point

Author: GrahamTheCoder

ICSharpCode.CodeConverter/CSharp/NodesVisitor.cs

@@ -945,11 +945,16 @@ private ExpressionSyntax GetConvertMethodForKeywordOrNull(SyntaxNode type)
 
             public override CSharpSyntaxNode VisitTryCastExpression(VBSyntax.TryCastExpressionSyntax node)
             {
-                return SyntaxFactory.BinaryExpression(
+                return ParenthesizeIfNested(node, SyntaxFactory.BinaryExpression(
                     SyntaxKind.AsExpression,
                     (ExpressionSyntax)node.Expression.Accept(TriviaConvertingVisitor),
                     (TypeSyntax)node.Type.Accept(TriviaConvertingVisitor)
-                );
+                ));
+            }
+
+            private static CSharpSyntaxNode ParenthesizeIfNested(VBSyntax.TryCastExpressionSyntax node, BinaryExpressionSyntax castExpression)
+            {
+                return node.Parent is VBSyntax.ExpressionSyntax ? (CSharpSyntaxNode) SyntaxFactory.ParenthesizedExpression(castExpression) : castExpression;
             }
 
             public override CSharpSyntaxNode VisitLiteralExpression(VBSyntax.LiteralExpressionSyntax node)

Tests/CSharp/TypeCastTests.cs

@@ -90,6 +90,7 @@ public void TryCastObjectToInteger()
     Private Sub Test()
         Dim o As Object = 5
         Dim i As System.Nullable(Of Integer) = TryCast(o, Integer)
+        Dim s As String = TryCast(o, Integer).ToString()
     End Sub
 End Class",
 @"class Class1
@@ -98,6 +99,7 @@ private void Test()
     {
         object o = 5;
         System.Nullable<int> i = o as int;
+        string s = (o as int).ToString();
     }
 }");
         }