diff --git a/src/runtime/mod.rs b/src/runtime/mod.rs
index e92c928f9546a889a5c5892e135cb11cf1d759d4..1948a0c9e337dba41d0d653ff175ca81a88eb8c3 100644
--- a/src/runtime/mod.rs
+++ b/src/runtime/mod.rs
@@ -231,7 +231,7 @@ trait Messengerlike {
 
 /////////////////////////////////
 impl Debug for SolutionStorage {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
         f.pad("Solutions: [")?;
         for (subtree_id, &index) in self.subtree_id_to_index.iter() {
             let sols = &self.subtree_solutions[index];
@@ -454,7 +454,7 @@ impl Predicate {
     }
 }
 impl Debug for Predicate {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
         f.pad("{")?;
         for (ChannelId { controller_id, channel_index }, &v) in self.assigned.iter() {
             f.write_fmt(format_args!(