X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDX%2FResolutionSpace.pm;h=c2bfff6137138e6462e4a0ad22435feee12d805a;hb=d69f4df43a8e53a1853113acb564b7fce6ac3957;hp=4210b025660aa7a71dfc790368538a0e5025c35d;hpb=0c1b8f3b476762fd15436c9fd29febf980ae0b5f;p=scpubgit%2FDX.git

diff --git a/lib/DX/ResolutionSpace.pm b/lib/DX/ResolutionSpace.pm
index 4210b02..c2bfff6 100644
--- a/lib/DX/ResolutionSpace.pm
+++ b/lib/DX/ResolutionSpace.pm
@@ -1,6 +1,7 @@
 package DX::ResolutionSpace;
 
 use DX::Utils qw(step);
+use DX::Step::Backtrack;
 use DX::Class;
 
 has proposition => (is => 'ro');
@@ -23,7 +24,7 @@ sub remaining_resolution_space {
 
 sub next_step {
   my ($self) = @_;
-  return undef unless @{$self->members};
+  return DX::Step::Backtrack->new unless @{$self->members};
   return step(
     resolves => $self->proposition,
     resolution_space => $self,