diff --git a/gc/mmtk/src/api.rs b/gc/mmtk/src/api.rs
index a1b94d5..5217eb4 100644
--- a/gc/mmtk/src/api.rs
+++ b/gc/mmtk/src/api.rs
@@ -107,10 +107,7 @@ pub extern "C" fn mmtk_builder_default() -> *mut MMTKBuilder {
     if let Some(threads) = mmtk_builder_default_parse_threads() {
         if !builder.options.threads.set(threads) {
             // MMTk will validate it and reject 0.
-            eprintln!(
-                "[FATAL] Failed to set the number of MMTk threads to {}",
-                threads
-            );
+            eprintln!("[FATAL] Failed to set the number of MMTk threads to {threads}");
             std::process::exit(1);
         }
     }
@@ -120,10 +117,7 @@ pub extern "C" fn mmtk_builder_default() -> *mut MMTKBuilder {
     let heap_max = mmtk_builder_default_parse_heap_max();
 
     if heap_min >= heap_max {
-        eprintln!(
-            "[FATAL] MMTK_HEAP_MIN({}) >= MMTK_HEAP_MAX({})",
-            heap_min, heap_max
-        );
+        eprintln!("[FATAL] MMTK_HEAP_MIN({heap_min}) >= MMTK_HEAP_MAX({heap_max})");
         std::process::exit(1);
     }
 
diff --git a/gc/mmtk/src/binding.rs b/gc/mmtk/src/binding.rs
index 619b7f2..811cbf8 100644
--- a/gc/mmtk/src/binding.rs
+++ b/gc/mmtk/src/binding.rs
@@ -119,7 +119,7 @@ impl RubyBinding {
     }
 
     pub fn register_wb_unprotected_object(&self, object: ObjectReference) {
-        debug!("Registering WB-unprotected object: {}", object);
+        debug!("Registering WB-unprotected object: {object}");
         let mut objects = self.wb_unprotected_objects.lock().unwrap();
         objects.insert(object);
     }
diff --git a/gc/mmtk/src/collection.rs b/gc/mmtk/src/collection.rs
index 0570b64..41c508a 100644
--- a/gc/mmtk/src/collection.rs
+++ b/gc/mmtk/src/collection.rs
@@ -41,10 +41,7 @@ impl Collection<Ruby> for VMCollection {
                 .name("MMTk Worker Thread".to_string())
                 .spawn(move || {
                     let ordinal = worker.ordinal;
-                    debug!(
-                        "Hello! This is MMTk Worker Thread running! ordinal: {}",
-                        ordinal
-                    );
+                    debug!("Hello! This is MMTk Worker Thread running! ordinal: {ordinal}");
                     crate::register_gc_thread(thread::current().id());
                     let ptr_worker = &mut *worker as *mut GCWorker<Ruby>;
                     let gc_thread_tls =
@@ -55,10 +52,7 @@ impl Collection<Ruby> for VMCollection {
                         GCThreadTLS::to_vwt(gc_thread_tls),
                         worker,
                     );
-                    debug!(
-                        "An MMTk Worker Thread is quitting. Good bye! ordinal: {}",
-                        ordinal
-                    );
+                    debug!("An MMTk Worker Thread is quitting. Good bye! ordinal: {ordinal}");
                     crate::unregister_gc_thread(thread::current().id());
                 })
                 .unwrap(),
diff --git a/gc/mmtk/src/scanning.rs b/gc/mmtk/src/scanning.rs
index 36c0f99..af43581 100644
--- a/gc/mmtk/src/scanning.rs
+++ b/gc/mmtk/src/scanning.rs
@@ -47,11 +47,7 @@ impl Scanning<Ruby> for VMScanning {
             );
             let forwarded_target = object_tracer.trace_object(target_object);
             if forwarded_target != target_object {
-                trace!(
-                    "  Forwarded target {} -> {}",
-                    target_object,
-                    forwarded_target
-                );
+                trace!("  Forwarded target {target_object} -> {forwarded_target}");
             }
             forwarded_target
         };
@@ -251,15 +247,11 @@ impl<F: RootsWorkFactory<RubySlot>> GCWork<Ruby> for ScanWbUnprotectedRoots<F> {
         VMScanning::collect_object_roots_in("wb_unprot_roots", gc_tls, &mut self.factory, || {
             for object in self.objects.iter().copied() {
                 if object.is_reachable() {
-                    debug!(
-                        "[wb_unprot_roots] Visiting WB-unprotected object (parent): {}",
-                        object
-                    );
+                    debug!("[wb_unprot_roots] Visiting WB-unprotected object (parent): {object}");
                     (upcalls().scan_object_ruby_style)(object);
                 } else {
                     debug!(
-                        "[wb_unprot_roots] Skipping young WB-unprotected object (parent): {}",
-                        object
+                        "[wb_unprot_roots] Skipping young WB-unprotected object (parent): {object}"
                     );
                 }
             }
diff --git a/gc/mmtk/src/weak_proc.rs b/gc/mmtk/src/weak_proc.rs
index 204dd20..0217673 100644
--- a/gc/mmtk/src/weak_proc.rs
+++ b/gc/mmtk/src/weak_proc.rs
@@ -103,7 +103,7 @@ impl GCWork<Ruby> for ProcessObjFreeCandidates {
 
         let n_cands = obj_free_candidates.len();
 
-        debug!("Total: {} candidates", n_cands);
+        debug!("Total: {n_cands} candidates");
 
         // Process obj_free
         let mut new_candidates = Vec::new();
@@ -112,11 +112,7 @@ impl GCWork<Ruby> for ProcessObjFreeCandidates {
             if object.is_reachable() {
                 // Forward and add back to the candidate list.
                 let new_object = object.forward();
-                trace!(
-                    "Forwarding obj_free candidate: {} -> {}",
-                    object,
-                    new_object
-                );
+                trace!("Forwarding obj_free candidate: {object} -> {new_object}");
                 new_candidates.push(new_object);
             } else {
                 (upcalls().call_obj_free)(object);
@@ -158,11 +154,10 @@ trait GlobalTableProcessingWork {
         let forward_object = |_worker, object: ObjectReference, _pin| {
             debug_assert!(
                 mmtk::memory_manager::is_mmtk_object(object.to_raw_address()).is_some(),
-                "{} is not an MMTk object",
-                object
+                "{object} is not an MMTk object"
             );
             let result = object.forward();
-            trace!("Forwarding reference: {} -> {}", object, result);
+            trace!("Forwarding reference: {object} -> {result}");
             result
         };
 
@@ -216,14 +211,10 @@ impl GCWork<Ruby> for UpdateWbUnprotectedObjectsList {
             if object.is_reachable() {
                 // Forward and add back to the candidate list.
                 let new_object = object.forward();
-                trace!(
-                    "Forwarding WB-unprotected object: {} -> {}",
-                    object,
-                    new_object
-                );
+                trace!("Forwarding WB-unprotected object: {object} -> {new_object}");
                 objects.insert(new_object);
             } else {
-                trace!("Removing WB-unprotected object from list: {}", object);
+                trace!("Removing WB-unprotected object from list: {object}");
             }
         }