diff --git a/src/quickfix.c b/src/quickfix.c
index 58c4227..df35163 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -1617,7 +1617,7 @@
 static bufref_T  qf_last_bufref = {NULL, 0};
 
 /*
- * Get buffer number for file "directory.fname".
+ * Get buffer number for file "directory/fname".
  * Also sets the b_has_qf_entry flag.
  */
     static int
@@ -2711,7 +2711,9 @@
     qi->qf_lists[idx].qf_index = 0;
 
     qf_clean_dir_stack(&qi->qf_dir_stack);
+    qi->qf_directory = NULL;
     qf_clean_dir_stack(&qi->qf_file_stack);
+    qi->qf_currfile = NULL;
 }
 
 /*
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 98afdb1..13c1482 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -1669,3 +1669,25 @@
   call assert_fails('caddexpr ""', 'E376:')
   let &efm = save_efm
 endfunc
+
+func Test_dirstack_cleanup()
+  " This used to cause a memory access in freed memory.
+  let save_efm = &efm
+  lexpr '0'
+  lopen
+  fun X(c)
+    let save_efm=&efm
+    set efm=%D%f
+    if a:c == 'c'
+      caddexpr '::'
+    else
+      laddexpr ':0:0'
+    endif
+    let &efm=save_efm
+  endfun
+  call X('c')
+  call X('l')
+  call setqflist([], 'r')
+  caddbuffer
+  let &efm = save_efm
+endfunc
diff --git a/src/version.c b/src/version.c
index c7f00a8..c4013e7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    84,
+/**/
     83,
 /**/
     82,