diff --git a/Upsilon/Binder/Binder.cs b/Upsilon/Binder/Binder.cs
index 3fa205a..81e8fdf 100644
--- a/Upsilon/Binder/Binder.cs
+++ b/Upsilon/Binder/Binder.cs
@@ -709,11 +709,10 @@ namespace Upsilon.Binder
                         return new BoundFullStopIndexExpression(expression, index, Type.Unknown, e.Span);
                     }
 
-                    if (expression.Kind == BoundKind.VariableExpression)
+                    var variableSymbol = ResolveVariable(expression);
+                    if (variableSymbol != null)
                     {
-                        var variableExpression     = (BoundVariableExpression)expression;
-                        var obj = variableExpression.Variable;
-                        var functionParameter = (FunctionParameterSymbol) obj.VariableSymbol;
+                        var functionParameter = (FunctionParameterSymbol) variableSymbol;
                         var udBoundDef = (UserDataBoundTypeDefinition)functionParameter.BoundTypeDefinition;
                         if (udBoundDef.Properties.TryGetValue(index, out var property))
                         {