diff --git a/lib/types.nix b/lib/types.nix
index e6f841766570..ab325fd20091 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -340,18 +340,80 @@ rec {
             let
               padWidth = stringLength (toString (length def.value));
               unnamed = i: unnamedPrefix + fixedWidthNumber padWidth i;
+              anyString = placeholder "name";
+              nameAttrs = [
+                { path = [ "environment" "etc" ];
+                  name = "target";
+                }
+                { path = [ "containers" anyString "bindMounts" ];
+                  name = "mountPoint";
+                }
+                { path = [ "programs" "ssh" "knownHosts" ];
+                  # hostNames is actually a list so we would need to handle it only when singleton
+                  name = "hostNames";
+                }
+                { path = [ "fileSystems" ];
+                  name = "mountPoint";
+                }
+                { path = [ "boot" "specialFileSystems" ];
+                  name = "mountPoint";
+                }
+                { path = [ "services" "znapzend" "zetup" ];
+                  name = "dataset";
+                }
+                { path = [ "services" "znapzend" "zetup" anyString "destinations" ];
+                  name = "label";
+                }
+                { path = [ "services" "geoclue2" "appConfig" ];
+                  name = "desktopID";
+                }
+                { path = [ "home-manager" "users" anyString "programs" "ssh" "matchBlocks" ];
+                  name = "host"; # https://github.com/rycee/home-manager/blob/e8dbc3561373b68d12decb3c0d7c1ba245f138f7/modules/programs/ssh.nix#L265
+                }
+                { path = [ "home-manager" "users" anyString "home" "file" ];
+                  name = "target"; # https://github.com/rycee/home-manager/blob/0e9b7aab3c6c27bf020402e0e2ef20b65c040552/modules/files.nix#L33
+                }
+                { path = [ "home-manager" "users" anyString "xdg" "configFile" ];
+                  name = "target"; # https://github.com/rycee/home-manager/blob/54de0e1d79a1370e57a8f23bef89f99f9b92ab67/modules/misc/xdg.nix#L41
+                }
+                { path = [ "home-manager" "users" anyString "xdg" "dataFile" ];
+                  name = "target"; # https://github.com/rycee/home-manager/blob/54de0e1d79a1370e57a8f23bef89f99f9b92ab67/modules/misc/xdg.nix#L58
+                }
+              ];
+              matched = let
+                equals = a: b: b == anyString || a == b;
+                fallback = { name = "name"; };
+              in findFirst ({ path, ... }: all (v: v == true) (zipListsWith equals loc path)) fallback nameAttrs;
+              nameAttr = matched.name;
+              nameValueOld = value:
+                if isList value then
+                  if length value > 0 then
+                    "[ " + concatMapStringsSep " " escapeNixString value + " ]"
+                  else
+                    "[ ]"
+                else
+                  escapeNixString value;
+              nameValueNew = value: unnamed:
+                if isList value then
+                  if length value > 0 then
+                    head value
+                  else
+                    unnamed
+                else
+                  value;
               res =
                 { inherit (def) file;
                   value = listToAttrs (
                     imap1 (elemIdx: elem:
-                      { name  = elem.name or (unnamed elemIdx);
+                      { name  = nameValueNew (elem.${nameAttr} or (unnamed elemIdx)) (unnamed elemIdx);
                         value = elem;
                       }) def.value);
                 };
               option = concatStringsSep "." loc;
               sample = take 3 def.value;
-              list = concatMapStrings (x: ''{ name = "${x.name or "unnamed"}"; ...} '') sample;
-              set = concatMapStrings (x: ''${x.name or "unnamed"} = {...}; '') sample;
+              more = lib.optionalString (length def.value > 3) "... ";
+              list = concatMapStrings (x: ''{ ${nameAttr} = ${nameValueOld (x.${nameAttr} or "unnamed")}; ...} '') sample;
+              set = concatMapStrings (x: ''${nameValueNew (x.${nameAttr} or "unnamed") "unnamed"} = {...}; '') sample;
               msg = ''
                 In file ${def.file}
                 a list is being assigned to the option config.${option}.
@@ -359,10 +421,10 @@ rec {
                 See https://git.io/fj2zm for more information.
                 Do
                   ${option} =
-                    { ${set}...}
+                    { ${set}${more}}
                 instead of
                   ${option} =
-                    [ ${list}...]
+                    [ ${list}${more}]
               '';
             in
               lib.warn msg res
diff --git a/nixos/modules/services/mail/postfix.nix b/nixos/modules/services/mail/postfix.nix
index d7378821440d..19e11b31d9ca 100644
--- a/nixos/modules/services/mail/postfix.nix
+++ b/nixos/modules/services/mail/postfix.nix
@@ -612,10 +612,7 @@ in
     {
 
       environment = {
-        etc = singleton
-          { source = "/var/lib/postfix/conf";
-            target = "postfix";
-          };
+        etc.postfix.source = "/var/lib/postfix/conf";
 
         # This makes it comfortable to run 'postqueue/postdrop' for example.
         systemPackages = [ pkgs.postfix ];
diff --git a/nixos/modules/services/mail/spamassassin.nix b/nixos/modules/services/mail/spamassassin.nix
index 07b3bf0420aa..75442c7cdb5e 100644
--- a/nixos/modules/services/mail/spamassassin.nix
+++ b/nixos/modules/services/mail/spamassassin.nix
@@ -124,7 +124,7 @@ in
     # Allow users to run 'spamc'.
 
     environment = {
-      etc = singleton { source = spamdEnv; target = "spamassassin"; };
+      etc.spamassassin.source = spamdEnv;
       systemPackages = [ pkgs.spamassassin ];
     };
 
diff --git a/pkgs/os-specific/linux/rfkill/udev.nix b/pkgs/os-specific/linux/rfkill/udev.nix
index 41dd3da9d31f..0575c46e28e3 100644
--- a/pkgs/os-specific/linux/rfkill/udev.nix
+++ b/pkgs/os-specific/linux/rfkill/udev.nix
@@ -8,18 +8,18 @@
 #   udev.packages = [ pkgs.rfkill_udev ];
 #
 # Add a hook script in the managed etc directory, e.g.:
-#   etc = [
-#     { source = pkgs.writeScript "rtfkill.hook" ''
-#         #!${pkgs.runtimeShell}
+#   etc."rfkill.hook" = {
+#     mode = "0755";
+#     text = ''
+#       #!${pkgs.runtimeShell}
 #
-#         if [ "$RFKILL_STATE" -eq "1" ]; then
-#           exec ${config.system.build.upstart}/sbin/initctl emit -n antenna-on
-#         else
-#           exec ${config.system.build.upstart}/sbin/initctl emit -n antenna-off
-#         fi
-#       '';
-#       target = "rfkill.hook";
-#     }
+#       if [ "$RFKILL_STATE" -eq "1" ]; then
+#         exec ${config.system.build.upstart}/sbin/initctl emit -n antenna-on
+#       else
+#         exec ${config.system.build.upstart}/sbin/initctl emit -n antenna-off
+#       fi
+#     '';
+#   }
 
 # Note: this package does not need the binaries
 # in the rfkill package.