diff --git a/src/typechecker/define.lisp b/src/typechecker/define.lisp
index 68482d118..5b15b1ca7 100644
--- a/src/typechecker/define.lisp
+++ b/src/typechecker/define.lisp
@@ -2078,7 +2078,7 @@ Returns (VALUES INFERRED-TYPE NODE SUBSTITUTIONS)")
 
                        (output-schemes
                          (loop :for ty :in output-qual-tys
-                               :collect (tc:quantify local-tvars ty)))
+                               :collect (tc:quantify (tc:apply-substitution subs local-tvars) ty)))
 
                        (rewrite-table
                          (loop :with table := (make-hash-table :test #'eq)