diff --git a/clap_generate/src/generators/shells/zsh.rs b/clap_generate/src/generators/shells/zsh.rs
index 9217a06d086f..0000371aaf87 100644
--- a/clap_generate/src/generators/shells/zsh.rs
+++ b/clap_generate/src/generators/shells/zsh.rs
@@ -535,7 +535,7 @@ fn write_positionals_of(p: &App) -> String {
                 .replace("[", "\\[")
                 .replace("]", "\\]")
                 .replace(":", "\\:"),
-            value_completion = value_completion(arg).unwrap_or("".to_string())
+            value_completion = value_completion(arg).unwrap_or_else(|| "".to_string())
         );
 
         debug!("write_positionals_of:iter: Wrote...{}", a);