diff --git a/collects/pkg/lib.rkt b/collects/pkg/lib.rkt
index ba55a79ae6..bf2d3a8681 100644
--- a/collects/pkg/lib.rkt
+++ b/collects/pkg/lib.rkt
@@ -992,10 +992,12 @@
                  (or (file-exists? f)
                      (file-exists? (path-replace-suffix f #".ss"))
                      (let-values ([(base name dir?) (split-path f)])
-                       (or (file-exists? (build-path base "compiled" (path-add-suffix f #".zo")))
+                       (or (file-exists? (build-path base "compiled" (path-add-suffix name #".zo")))
                            (file-exists? (build-path base "compiled" (path-add-suffix
-                                                                      (path-replace-suffix f #".ss") 
-                                                                      #".zo")))))))
+                                                                      (path-replace-suffix name #".ss")
+                                                                      #".zo"))))))
+                 (or (not updating?)
+                     (not (equal? pkg-name (path->pkg f)))))
             ;; This module is already installed
             (cons (path->pkg f) mp)]
            [else
diff --git a/collects/tests/pkg/test-catalogs-api.rkt b/collects/tests/pkg/test-catalogs-api.rkt
index 6fa8d8e8fb..c0e78b0261 100644
--- a/collects/tests/pkg/test-catalogs-api.rkt
+++ b/collects/tests/pkg/test-catalogs-api.rkt
@@ -33,9 +33,11 @@
     (get-pkg-content (pkg-desc "http://localhost:9999/pkg-test1.zip" #f #f #f)))
 
   (check-equal? cksum cksum1)
-  (check-equal? mods '((lib "pkg-test1/conflict.rkt")
-                       (lib "pkg-test1/main.rkt") 
-                       (lib "pkg-test1/update.rkt")))
+  (check-equal? (sort mods string<? #:key cadr)
+                '((lib "data/empty-set.rkt")
+                  (lib "pkg-test1/conflict.rkt")
+                  (lib "pkg-test1/main.rkt")
+                  (lib "pkg-test1/update.rkt")))
   (check-equal? deps '())
 
   (define-values (cksum2 mods2 deps2) 
diff --git a/collects/tests/pkg/test-pkgs/pkg-test1/data/empty-set.rkt b/collects/tests/pkg/test-pkgs/pkg-test1/data/empty-set.rkt
new file mode 100644
index 0000000000..e7ef898034
--- /dev/null
+++ b/collects/tests/pkg/test-pkgs/pkg-test1/data/empty-set.rkt
@@ -0,0 +1,6 @@
+#lang racket/base
+
+(define empty-set '())
+
+;; This module tests splicing into an existing collection
+;; (and the associated conflict checking).