diff --git a/src/lang/Nub.Lang/Diagnostics/Diagnostic.cs b/src/lang/Nub.Lang/Diagnostics/Diagnostic.cs
index eb75061..f53dca8 100644
--- a/src/lang/Nub.Lang/Diagnostics/Diagnostic.cs
+++ b/src/lang/Nub.Lang/Diagnostics/Diagnostic.cs
@@ -116,10 +116,10 @@ public class Diagnostic
         var lineNumWidth = Math.Min(endLine + contextLines, lines.Length).ToString().Length;
 
         var contextStart = Math.Max(1, startLine - contextLines);
-        var contextEnd = Math.Min(lines.Length, endLine + contextLines);
+        var contextEnd = Math.Min(lines.Length + 1, endLine + contextLines);
 
         var contextWidth = 0;
-        for (var i = contextStart; i < contextEnd; i++)
+        for (var i = contextStart; i <= contextEnd; i++)
         {
             if (lines[i - 1].Length > contextWidth)
             {