diff --git a/src/lsp/defstruct.lsp b/src/lsp/defstruct.lsp
index a1c79b8be..498108511 100644
--- a/src/lsp/defstruct.lsp
+++ b/src/lsp/defstruct.lsp
@@ -490,7 +490,7 @@ as a STRUCTURE doc and can be retrieved by (documentation 'NAME 'structure)."
 
     ;; Check the named option and set the predicate.
     (when (and type (not named))
-      (when predicate-specified
+      (when (and predicate-specified predicate)
         (error "~S is an illegal structure predicate."
                predicate))
       (setq predicate nil))