diff --git a/src/com/google/inject/commands/CommandRecorder.java b/src/com/google/inject/commands/CommandRecorder.java
index 3f75a00..807d912 100644
--- a/src/com/google/inject/commands/CommandRecorder.java
+++ b/src/com/google/inject/commands/CommandRecorder.java
@@ -68,7 +68,7 @@
   /**
    * Records the commands executed by {@code modules}.
    */
-  public List<Command> recordCommands(Iterable<Module> modules) {
+  public List<Command> recordCommands(Iterable<? extends Module> modules) {
     RecordingBinder binder = new RecordingBinder();
     for (Module module : modules) {
       binder.install(module);
diff --git a/src/com/google/inject/commands/CommandReplayer.java b/src/com/google/inject/commands/CommandReplayer.java
index c797de0..708e550 100644
--- a/src/com/google/inject/commands/CommandReplayer.java
+++ b/src/com/google/inject/commands/CommandReplayer.java
@@ -39,7 +39,7 @@
    * Returns a module that executes the specified commands
    * using this executing visitor.
    */
-  public final Module createModule(final Iterable<Command> commands) {
+  public final Module createModule(final Iterable<? extends Command> commands) {
     return new Module() {
       public void configure(Binder binder) {
         replay(binder, commands);
@@ -50,7 +50,7 @@
   /**
    * Replays {@code commands} against {@code binder}.
    */
-  public final void replay(final Binder binder, Iterable<Command> commands) {
+  public final void replay(final Binder binder, Iterable<? extends Command> commands) {
     checkNotNull(binder, "binder");
     checkNotNull(commands, "commands");