diff --git a/collects/typed-scheme/optimizer/optimizer.rkt b/collects/typed-scheme/optimizer/optimizer.rkt
index 04bc1c790e..f9bc201792 100644
--- a/collects/typed-scheme/optimizer/optimizer.rkt
+++ b/collects/typed-scheme/optimizer/optimizer.rkt
@@ -37,7 +37,9 @@
   ;; boring cases, just recur down
   (pattern ((~and op (~or (~literal #%plain-lambda) (~literal define-values)))
             formals e:expr ...)
-           #:with opt #`(op formals #,@(syntax-map (optimize) #'(e ...))))
+           #:with opt (syntax-track-origin (quasisyntax/loc this-syntax (op formals #,@(syntax-map (optimize) #'(e ...))))
+                                           this-syntax
+                                           #'op))
   (pattern (case-lambda [formals e:expr ...] ...)
            ;; optimize all the bodies
            #:with (opt-parts ...)