diff --git a/infer/src/checkers/control.ml b/infer/src/checkers/control.ml
index 205f7fd94..c0634f6e1 100644
--- a/infer/src/checkers/control.ml
+++ b/infer/src/checkers/control.ml
@@ -164,7 +164,8 @@ module TransferFunctionsControlDeps (CFG : ProcCfg.S) = struct
           astate' )
     | _ ->
         (* Exit node must be a prune node *)
-        assert (not (ExitNodeToLoopHeads.mem node exit_map)) ;
+        if ExitNodeToLoopHeads.mem node exit_map then
+          L.internal_error "Exit node must be a prune node!" ;
         astate'