diff --git a/Upsilon/Binder/Binder.cs b/Upsilon/Binder/Binder.cs
index 02c3329..66cc4fb 100644
--- a/Upsilon/Binder/Binder.cs
+++ b/Upsilon/Binder/Binder.cs
@@ -712,6 +712,8 @@ namespace Upsilon.Binder
                         {
                             return new BoundFullStopIndexExpression(expression, index, property.Type, e.Span);
                         }
+                        _diagnostics.LogError($"No variable '{index}' found on type '{udBoundDef.Name}'.",
+                            e.Span);
                     }
                     return new BoundFullStopIndexExpression(expression, index, Type.Unknown, e.Span);
                 case Type.Unknown: