diff --git a/crates/wasmtime/src/externals.rs b/crates/wasmtime/src/externals.rs
index 11368216c2..177edc18a2 100644
--- a/crates/wasmtime/src/externals.rs
+++ b/crates/wasmtime/src/externals.rs
@@ -18,7 +18,7 @@ use wasmtime_runtime::{self as runtime, InstanceHandle};
 /// as well as required by [`Instance::new`](crate::Instance::new). In other
 /// words, this is the type of extracted values from an instantiated module, and
 /// it's also used to provide imported values when instantiating a module.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub enum Extern {
     /// A WebAssembly `func` which can be called.
     Func(Func),
diff --git a/crates/wasmtime/src/memory.rs b/crates/wasmtime/src/memory.rs
index 396c9fae15..677400d1ee 100644
--- a/crates/wasmtime/src/memory.rs
+++ b/crates/wasmtime/src/memory.rs
@@ -818,6 +818,12 @@ impl SharedMemory {
     }
 }
 
+impl std::fmt::Debug for SharedMemory {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("SharedMemory").finish_non_exhaustive()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::*;