diff --git a/fish-rust/src/flog.rs b/fish-rust/src/flog.rs
index 62abbc366..13a9798d0 100644
--- a/fish-rust/src/flog.rs
+++ b/fish-rust/src/flog.rs
@@ -133,6 +133,8 @@ pub mod categories {
         (path, "path", "Searching/using paths");
 
         (screen, "screen", "Screen repaints");
+
+        (refcell, "refcell", "Refcell dynamic borrowing");
     );
 }
 
diff --git a/fish-rust/src/global_safety.rs b/fish-rust/src/global_safety.rs
index b54d0ddc1..f3c8788ff 100644
--- a/fish-rust/src/global_safety.rs
+++ b/fish-rust/src/global_safety.rs
@@ -1,4 +1,7 @@
+use crate::flog::FLOG;
+use std::cell::{Ref, RefMut};
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::MutexGuard;
 
 #[derive(Debug)]
 pub struct RelaxedAtomicBool(AtomicBool);
@@ -23,3 +26,103 @@ impl Clone for RelaxedAtomicBool {
         Self(AtomicBool::new(self.load()))
     }
 }
+
+pub struct DebugRef<'a, T>(Ref<'a, T>);
+
+impl<'a, T> DebugRef<'a, T> {
+    pub fn new(r: Ref<'a, T>) -> Self {
+        FLOG!(
+            refcell,
+            "CREATE DebugRef",
+            std::backtrace::Backtrace::capture()
+        );
+        Self(r)
+    }
+}
+
+impl<'a, T> Drop for DebugRef<'a, T> {
+    fn drop(&mut self) {
+        FLOG!(
+            refcell,
+            "DROP DebugRef",
+            std::backtrace::Backtrace::capture()
+        );
+    }
+}
+
+impl<'a, T> std::ops::Deref for DebugRef<'a, T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+pub struct DebugRefMut<'a, T>(RefMut<'a, T>);
+
+impl<'a, T> DebugRefMut<'a, T> {
+    pub fn new(r: RefMut<'a, T>) -> Self {
+        FLOG!(
+            refcell,
+            "CREATE DebugRefMut",
+            std::backtrace::Backtrace::capture()
+        );
+        Self(r)
+    }
+}
+
+impl<'a, T> Drop for DebugRefMut<'a, T> {
+    fn drop(&mut self) {
+        FLOG!(
+            refcell,
+            "DROP DebugRefMut",
+            std::backtrace::Backtrace::capture()
+        );
+    }
+}
+impl<'a, T> std::ops::Deref for DebugRefMut<'a, T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a, T> std::ops::DerefMut for DebugRefMut<'a, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+pub struct DebugMutexGuard<'a, T>(MutexGuard<'a, T>);
+
+impl<'a, T> DebugMutexGuard<'a, T> {
+    pub fn new(r: MutexGuard<'a, T>) -> Self {
+        FLOG!(
+            refcell,
+            "CREATE DebugMutexGuard",
+            std::backtrace::Backtrace::capture()
+        );
+        Self(r)
+    }
+}
+
+impl<'a, T> Drop for DebugMutexGuard<'a, T> {
+    fn drop(&mut self) {
+        FLOG!(
+            refcell,
+            "DROP DebugMutexGuard",
+            std::backtrace::Backtrace::capture()
+        );
+    }
+}
+
+impl<'a, T> std::ops::Deref for DebugMutexGuard<'a, T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl<'a, T> std::ops::DerefMut for DebugMutexGuard<'a, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}