diff --git a/opam b/opam
index 0e2dace148ea7bf906d2aa9752bc35e685a8c911..2a4f855ecbef2895e59e2a14ea7144c286939cc3 100644
--- a/opam
+++ b/opam
@@ -9,5 +9,5 @@ build: [make "-j%{jobs}%"]
 install: [make "install"]
 remove: [ "sh" "-c" "rm -rf '%{lib}%/coq/user-contrib/actris" ]
 depends: [
-  "coq-iris-heap-lang" { (= "dev.2020-11-11.4.e34f8ac7") | (= "dev") }
+  "coq-iris-heap-lang" { (= "dev.2020-11-26.2.03b317f4") | (= "dev") }
 ]
diff --git a/theories/utils/switch.v b/theories/utils/switch.v
index f4b820ae1d14787a210e29ff548e7ddf88ad5fa8..1f927178111e4a874981480509b5589d4b61f3c3 100644
--- a/theories/utils/switch.v
+++ b/theories/utils/switch.v
@@ -60,6 +60,7 @@ Proof.
   iInduction vs as [|v vs] "IH" forall (i ws); csimpl.
   { rewrite left_id_L.
     iApply (wp_wand with "H"); iIntros (v) "H". by iApply wp_value. }
+  pose proof @pure_exec_fill.
   wp_pures. iApply wp_bind.
   iEval (rewrite -subst_map_insert insert_union_singleton_l).
   iApply "IH". rewrite assoc_L insert_union_singleton_r //