Escape keywords in parameter names - fixes #1092

Author: GrahamTheCoder

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### VB -> C#
 
+* Escape parameter names [#1092](https://github.com/icsharpcode/CodeConverter/issues/1092)
 
 ### C# -> VB
 

CodeConverter/CSharp/ExpressionNodeVisitor.cs

@@ -1747,7 +1747,7 @@ async Task<ArgumentSyntax> ConvertArg(VBSyntax.ArgumentSyntax arg, int argIndex)
 
             var argSyntax = await arg.AcceptAsync<ArgumentSyntax>(TriviaConvertingExpressionVisitor);
             if (forceNamedParameters && !arg.IsNamed && parameterSymbol != null) {
-                return argSyntax.WithNameColon(SyntaxFactory.NameColon(parameterSymbol.Name));
+                return argSyntax.WithNameColon(SyntaxFactory.NameColon(SyntaxFactory.IdentifierName(CommonConversions.CsEscapedIdentifier(parameterSymbol.Name))));
             }
 
             return argSyntax;

Tests/CSharp/MemberTests/MemberTests.cs

@@ -2296,6 +2296,33 @@ public void InterfaceWithOptionalParameters_S(int i = 0)
 ");
     }
 
+    [Fact]
+    public async Task OptionalParameterWithReservedName_1092_Async()
+    {
+        await TestConversionVisualBasicToCSharpAsync(
+            @"
+Public Class WithOptionalParameters
+    Sub S1(Optional a As Object = Nothing, Optional [default] As String = """")
+    End Sub
+
+    Sub S()
+        S1(, ""a"")
+    End Sub
+End Class", @"
+public partial class WithOptionalParameters
+{
+    public void S1(object a = null, string @default = """")
+    {
+    }
+
+    public void S()
+    {
+        S1(@default: ""a"");
+    }
+}
+");
+    }
+
 
     [Fact]
     public async Task ExplicitInterfaceImplementationOptionalParametersAsync()