diff --git a/collects/tests/mzscheme/optimize.ss b/collects/tests/mzscheme/optimize.ss
index d1c99961da..e8d0d50915 100644
--- a/collects/tests/mzscheme/optimize.ss
+++ b/collects/tests/mzscheme/optimize.ss
@@ -295,7 +295,8 @@
 (test-comp (normalize-depth '(let* ([i (cons 0 1)][g i][h (car g)][m h]) m))
 	   (normalize-depth '(let* ([i (cons 0 1)][h (car i)]) h)))
 
-(set! maybe-different-depths? #t)
+;; The current optimizer reset depths correctly:
+;; (set! maybe-different-depths? #t)
 
 (require #%kernel) ; 
 
@@ -316,4 +317,20 @@
 (test-comp '(let ([x 3][y 4]) (+ x y))
 	   '((lambda (x y) (+ x y)) 3 4))
 
+(test-comp '(let ([x 1][y 2]) x)
+	   '1)
+(test-comp '(let ([x 1][y 2]) (+ y x))
+	   '3)
+(test-comp '(let ([x 1][y 2]) (cons x y))
+	   '(cons 1 2))
+(test-comp '(let* ([x (cons 1 1)][y x]) (cons x y))
+	   '(let* ([x (cons 1 1)]) (cons x x)))
+(test-comp '(let* ([x 1][y (add1 x)]) (+ y x))
+	   '3)
+(test-comp '(letrec ([x (cons 1 1)][y x]) (cons x y))
+	   '(letrec ([x (cons 1 1)][y x]) (cons x x)))
+
+(test-comp '(let ([f (lambda (x) x)]) f)
+	   (syntax-property (datum->syntax-object #f '(lambda (x) x)) 'inferred-name 'f))
+
 (report-errs)
diff --git a/collects/tests/mzscheme/syntax.ss b/collects/tests/mzscheme/syntax.ss
index ee05b947a4..6bb7d1855d 100644
--- a/collects/tests/mzscheme/syntax.ss
+++ b/collects/tests/mzscheme/syntax.ss
@@ -1045,4 +1045,42 @@
 (define x 5)
 (test 5 '#%top (#%top . x))
 
+;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Tests related to bytecode optimizer.
+;; The (if (let ([x M]) (if x x N)) ...)
+;;   => (if (if M #t N) ...)
+;; converter drops the variable `x', which means
+;; that other mappings must adjust
+
+(let ([val 0])
+  (let ([g (lambda ()
+	     (letrec ([f (lambda (z x)
+			   (if (let ([w (even? 81)])
+				 (if w
+				     w
+				     (let ([y x])
+				       (set! x 7)
+				       (set! val (+ y 5)))))
+			       'yes
+			       'no))])
+	       (f 0 11)))])
+    (g))
+  (test 16 values val))
+
+(let ([val 0])
+  (let ([g (lambda ()
+	     (letrec ([f (lambda (z x)
+			   (if (let ([w (even? 81)])
+				 (if w
+				     w
+				     (let ([y x])
+				       (set! val (+ y 5)))))
+			       'yes
+			       'no))])
+	       (f 0 11)))])
+    (g))
+  (test 16 values val))
+
+;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
 (report-errs)