diff --git a/lib/modules.nix b/lib/modules.nix
index c3c903c1dfa8..00c7712487bd 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -592,11 +592,14 @@ rec {
     { options = setAttrByPath optionName (mkOption {
         visible = false;
       });
-      config.warnings =
-        let opt = getAttrFromPath optionName options; in
-        optional opt.isDefined ''
+      config.assertions =
+        let opt = getAttrFromPath optionName options; in [{
+          assertion = !opt.isDefined;
+          message = ''
             The option definition `${showOption optionName}' in ${showFiles opt.files} no longer has any effect; please remove it.
-            ${replacementInstructions}'';
+            ${replacementInstructions}
+          '';
+        }];
     };
 
   /* Return a module that causes a warning to be shown if the
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix b/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
index 554377df37ba..ba852fea4336 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
@@ -49,6 +49,6 @@ in
     (mkRemovedOptionModule [ "insecure" ] ''
       This option was replaced by 'prometheus.exporters.nginx.sslVerify'.
     '')
-    ({ options.warnings = options.warnings; })
+    ({ options.warnings = options.warnings; options.assertions = options.assertions; })
   ];
 }
diff --git a/nixos/modules/tasks/network-interfaces.nix b/nixos/modules/tasks/network-interfaces.nix
index 29310f6f24aa..3038be6dbab4 100644
--- a/nixos/modules/tasks/network-interfaces.nix
+++ b/nixos/modules/tasks/network-interfaces.nix
@@ -305,7 +305,7 @@ let
             optional (defined ipv6Address && defined ipv6PrefixLength)
             { address = ipv6Address; prefixLength = ipv6PrefixLength; }))
 
-        ({ options.warnings = options.warnings; })
+        ({ options.warnings = options.warnings; options.assertions = options.assertions; })
       ];
 
   };