diff --git a/autoenv.zsh b/autoenv.zsh
index 2428c92..8387558 100644
--- a/autoenv.zsh
+++ b/autoenv.zsh
@@ -43,7 +43,9 @@ autoenv_source_parent() {
 # Internal functions. {{{
 # Internal: stack of entered (and handled) directories. {{{
 typeset -a _autoenv_stack_entered
+_autoenv_stack_entered=()
 typeset -A _autoenv_stack_entered_mtime
+_autoenv_stack_entered_mtime=()
 
 # Add an entry to the stack, and remember its mtime.
 _autoenv_stack_entered_add() {