diff --git a/vm/src/function.rs b/vm/src/function.rs
index a505ad477..19495c772 100644
--- a/vm/src/function.rs
+++ b/vm/src/function.rs
@@ -34,6 +34,7 @@ macro_rules! into_func_args_from_tuple {
         where
             $($T: IntoPyObject,)*
         {
+            #[inline]
             fn into_args(self, vm: &VirtualMachine) -> FuncArgs {
                 let ($($n,)*) = self;
                 vec![$($n.into_pyobject(vm),)*].into()
diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
index a2d29e9f7..15f1484ec 100644
--- a/vm/src/pyobject.rs
+++ b/vm/src/pyobject.rs
@@ -477,6 +477,7 @@ impl<T: PyValue> Deref for PyRefExact<T> {
     }
 }
 impl<T: PyValue> IntoPyObject for PyRefExact<T> {
+    #[inline]
     fn into_pyobject(self, _vm: &VirtualMachine) -> PyObjectRef {
         self.obj.into_object()
     }
@@ -833,18 +834,21 @@ pub trait IntoPyObject {
 }
 
 impl<T: PyObjectPayload> IntoPyObject for PyRef<T> {
+    #[inline]
     fn into_pyobject(self, _vm: &VirtualMachine) -> PyObjectRef {
         self.into_object()
     }
 }
 
 impl IntoPyObject for PyCallable {
+    #[inline]
     fn into_pyobject(self, _vm: &VirtualMachine) -> PyObjectRef {
         self.into_object()
     }
 }
 
 impl IntoPyObject for PyObjectRef {
+    #[inline]
     fn into_pyobject(self, _vm: &VirtualMachine) -> PyObjectRef {
         self
     }
@@ -856,6 +860,7 @@ impl<T> IntoPyObject for T
 where
     T: PyValue + Sized,
 {
+    #[inline]
     fn into_pyobject(self, vm: &VirtualMachine) -> PyObjectRef {
         PyValue::into_object(self, vm)
     }
@@ -896,26 +901,13 @@ cfg_if::cfg_if! {
 pub trait PyValue: fmt::Debug + PyThreadingConstraint + Sized + 'static {
     fn class(vm: &VirtualMachine) -> &PyTypeRef;
 
+    #[inline]
     fn into_object(self, vm: &VirtualMachine) -> PyObjectRef {
         self.into_ref(vm).into_object()
     }
 
     fn into_ref(self, vm: &VirtualMachine) -> PyRef<Self> {
-        self.into_ref_with_type_unchecked(Self::class(vm).clone(), vm)
-    }
-
-    fn into_ref_with_type(self, vm: &VirtualMachine, cls: PyTypeRef) -> PyResult<PyRef<Self>> {
-        let class = Self::class(vm);
-        if cls.issubclass(class) {
-            Ok(self.into_ref_with_type_unchecked(cls, vm))
-        } else {
-            let subtype = vm.to_str(cls.as_object())?;
-            let basetype = vm.to_str(cls.as_object())?;
-            Err(vm.new_type_error(format!("{} is not a subtype of {}", subtype, basetype)))
-        }
-    }
-
-    fn into_ref_with_type_unchecked(self, cls: PyTypeRef, vm: &VirtualMachine) -> PyRef<Self> {
+        let cls = Self::class(vm).clone();
         let dict = if cls.slots.flags.has_feature(PyTpFlags::HAS_DICT) {
             Some(vm.ctx.new_dict())
         } else {
@@ -923,6 +915,22 @@ pub trait PyValue: fmt::Debug + PyThreadingConstraint + Sized + 'static {
         };
         PyRef::new_ref(self, cls, dict)
     }
+
+    fn into_ref_with_type(self, vm: &VirtualMachine, cls: PyTypeRef) -> PyResult<PyRef<Self>> {
+        let exact_class = Self::class(vm);
+        if cls.issubclass(exact_class) {
+            let dict = if cls.slots.flags.has_feature(PyTpFlags::HAS_DICT) {
+                Some(vm.ctx.new_dict())
+            } else {
+                None
+            };
+            Ok(PyRef::new_ref(self, cls, dict))
+        } else {
+            let subtype = vm.to_str(cls.as_object())?;
+            let basetype = vm.to_str(exact_class.as_object())?;
+            Err(vm.new_type_error(format!("{} is not a subtype of {}", subtype, basetype)))
+        }
+    }
 }
 
 pub trait PyObjectPayload: Any + fmt::Debug + PyThreadingConstraint + 'static {}
diff --git a/vm/src/vm.rs b/vm/src/vm.rs
index 5e9b32203..b6e2f97db 100644
--- a/vm/src/vm.rs
+++ b/vm/src/vm.rs
@@ -971,38 +971,44 @@ impl VirtualMachine {
     }
 
     /// Call registered trace function.
+    #[inline]
     fn trace_event(&self, event: TraceEvent) -> PyResult<()> {
         if self.use_tracing.get() {
-            let trace_func = self.trace_func.borrow().clone();
-            let profile_func = self.profile_func.borrow().clone();
-            if self.is_none(&trace_func) && self.is_none(&profile_func) {
-                return Ok(());
-            }
+            self._trace_event_inner(event)
+        } else {
+            Ok(())
+        }
+    }
+    fn _trace_event_inner(&self, event: TraceEvent) -> PyResult<()> {
+        let trace_func = self.trace_func.borrow().clone();
+        let profile_func = self.profile_func.borrow().clone();
+        if self.is_none(&trace_func) && self.is_none(&profile_func) {
+            return Ok(());
+        }
 
-            let frame_ref = self.current_frame();
-            if frame_ref.is_none() {
-                return Ok(());
-            }
+        let frame_ref = self.current_frame();
+        if frame_ref.is_none() {
+            return Ok(());
+        }
 
-            let frame = frame_ref.unwrap().as_object().clone();
-            let event = self.ctx.new_str(event.to_string());
-            let args = vec![frame, event, self.ctx.none()];
+        let frame = frame_ref.unwrap().as_object().clone();
+        let event = self.ctx.new_str(event.to_string());
+        let args = vec![frame, event, self.ctx.none()];
 
-            // temporarily disable tracing, during the call to the
-            // tracing function itself.
-            if !self.is_none(&trace_func) {
-                self.use_tracing.set(false);
-                let res = self.invoke(&trace_func, args.clone());
-                self.use_tracing.set(true);
-                res?;
-            }
+        // temporarily disable tracing, during the call to the
+        // tracing function itself.
+        if !self.is_none(&trace_func) {
+            self.use_tracing.set(false);
+            let res = self.invoke(&trace_func, args.clone());
+            self.use_tracing.set(true);
+            res?;
+        }
 
-            if !self.is_none(&profile_func) {
-                self.use_tracing.set(false);
-                let res = self.invoke(&profile_func, args);
-                self.use_tracing.set(true);
-                res?;
-            }
+        if !self.is_none(&profile_func) {
+            self.use_tracing.set(false);
+            let res = self.invoke(&profile_func, args);
+            self.use_tracing.set(true);
+            res?;
         }
         Ok(())
     }