diff --git a/collects/tests/typed-racket/optimizer/tests/vector-bounds-check.rkt b/collects/tests/typed-racket/optimizer/tests/vector-bounds-check.rkt
new file mode 100644
index 0000000000..e43b3fe349
--- /dev/null
+++ b/collects/tests/typed-racket/optimizer/tests/vector-bounds-check.rkt
@@ -0,0 +1,24 @@
+#;
+(
+1.0
+1.0
+)
+
+#lang typed/racket
+(require racket/flonum)
+
+(define: been-there-vector?   : Boolean #f)
+(define: been-there-flvector? : Boolean #f)
+(define (make-my-vector)
+  (if been-there-vector?
+      (error "make-my-vector should only be called once!")
+      (set! been-there-vector? #t))
+  (ann (vector 1.0 2.0 3.0) (Vectorof Flonum)))
+(define (make-my-flvector)
+  (if been-there-flvector?
+      (error "make-my-flvector should only be called once!")
+      (set! been-there-flvector? #t))
+  (flvector 1.0 2.0 3.0))
+
+(vector-ref (make-my-vector) 0)
+(flvector-ref (make-my-flvector) 0)
diff --git a/collects/typed-racket/optimizer/vector.rkt b/collects/typed-racket/optimizer/vector.rkt
index 85b41935f9..d22fd48700 100644
--- a/collects/typed-racket/optimizer/vector.rkt
+++ b/collects/typed-racket/optimizer/vector.rkt
@@ -89,7 +89,7 @@
                             [new-v #,((optimize) #'v)])
                         ;; do the impersonator check up front, to avoid doing it twice (length and op)
                         (if (impersonator? new-v)
-                            (if #,(let ([one-sided #'(unsafe-fx< new-i (unsafe-vector*-length v))])
+                            (if #,(let ([one-sided #'(unsafe-fx< new-i (unsafe-vector*-length new-v))])
                                     (if i-known-nonneg?
                                         ;; we know it's nonnegative, one-sided check
                                         one-sided
@@ -98,7 +98,7 @@
                                 (op.unsafe new-v new-i #,@(syntax-map (optimize) #'(new ...)))
                                 #,safe-fallback) ; will error. to give the right error message
                             ;; not an impersonator, can use unsafe-vector* ops
-                            (if #,(let ([one-sided #'(unsafe-fx< new-i (unsafe-vector-length v))])
+                            (if #,(let ([one-sided #'(unsafe-fx< new-i (unsafe-vector-length new-v))])
                                     (if i-known-nonneg?
                                         one-sided
                                         #`(and (unsafe-fx>= new-i 0)
@@ -116,7 +116,7 @@
                         [i-known-nonneg? (subtypeof? #'i -NonNegFixnum)])
                     #`(let ([new-i #,((optimize) #'i)]
                             [new-v #,((optimize) #'v)])
-                        (if #,(let ([one-sided #'(unsafe-fx< new-i (unsafe-flvector-length v))])
+                        (if #,(let ([one-sided #'(unsafe-fx< new-i (unsafe-flvector-length new-v))])
                                 (if i-known-nonneg?
                                     one-sided
                                     #`(and (unsafe-fx>= new-i 0)