diff --git a/theories/lifetime/model/definitions.v b/theories/lifetime/model/definitions.v
index 7f286d7a9fa12aacc86e85680eb88a815fac89fc..5b0453acbea8ca315a54ab601267fc682b811a67 100644
--- a/theories/lifetime/model/definitions.v
+++ b/theories/lifetime/model/definitions.v
@@ -27,8 +27,6 @@ Inductive bor_state :=
   | Bor_in
   | Bor_open (q : frac)
   | Bor_rebor (κ : lft).
-Instance bor_state_eq_dec : EqDecision bor_state.
-Proof. solve_decision. Defined.
 Canonical bor_stateC := leibnizC bor_state.
 
 Record lft_names := LftNames {
@@ -36,8 +34,6 @@ Record lft_names := LftNames {
   cnt_name : gname;
   inh_name : gname
 }.
-Instance lft_names_eq_dec : EqDecision lft_names.
-Proof. solve_decision. Defined.
 Canonical lft_namesC := leibnizC lft_names.
 
 Definition lft_stateR := csumR fracR unitR.