diff --git a/src/Gitolite/Rc.pm b/src/Gitolite/Rc.pm
index 49ca35d..6a7dd32 100644
--- a/src/Gitolite/Rc.pm
+++ b/src/Gitolite/Rc.pm
@@ -216,6 +216,7 @@ __DATA__
     SYNTACTIC_SUGAR             =>
         [
             # 'continuation-lines',
+            'legacy-delegation-abort',
         ],
 
     # comment out or uncomment as needed
diff --git a/src/syntactic-sugar/keysubdirs-as-groups b/src/syntactic-sugar/keysubdirs-as-groups
index 75c015d..69a69b1 100755
--- a/src/syntactic-sugar/keysubdirs-as-groups
+++ b/src/syntactic-sugar/keysubdirs-as-groups
@@ -7,7 +7,7 @@
 # taken as the group name.
 
 sub sugar_script {
-    trace( 2, "running 'keysubdirs-as-groups' sugar script..." );
+    Gitolite::Common::trace( 2, "running 'keysubdirs-as-groups' sugar script..." );
     my $lines = shift;
 
     my @out = @{$lines};
diff --git a/src/syntactic-sugar/legacy-delegation-abort b/src/syntactic-sugar/legacy-delegation-abort
new file mode 100755
index 0000000..1625632
--- /dev/null
+++ b/src/syntactic-sugar/legacy-delegation-abort
@@ -0,0 +1,26 @@
+# vim: syn=perl:
+
+# "sugar script" (syntactic sugar helper) for gitolite3
+
+# Aborts if you appear to be using legacy delegation.
+
+# Note: you cannot fix this using sugar; subconf processing has already
+# happened by the time it gets to this point.
+
+# TODO: supply doc keyword, and that doc should tell people to add this to the
+# end of the main conf file:
+
+#       repo gitolite-admin
+#           -   NAME/       =   @all
+#       subconf "fragments/*.conf"
+
+sub sugar_script {
+    Gitolite::Common::trace( 2, "running 'legacy-delegation-warn' sugar script..." );
+    my $lines = shift;
+
+    my $text = join("\n", @$lines);
+    if ($text =~ m(NAME/conf/fragments/) and $text !~ /^subconf /m) {
+        die "\t**** ABORT ****\nYou may be using legacy delegation; see docs\n";
+    }
+    return $lines;
+}