diff --git a/vm/src/builtins/pytype.rs b/vm/src/builtins/pytype.rs
index a335901f4..cc6565447 100644
--- a/vm/src/builtins/pytype.rs
+++ b/vm/src/builtins/pytype.rs
@@ -629,7 +629,7 @@ fn subtype_get_dict(obj: PyObjectRef, vm: &VirtualMachine) -> PyResult {
     // TODO: obj.class().as_pyref() need to be supported
     let cls = obj.clone_class();
     let ret = match find_base_dict_descr(&cls, vm) {
-        Some(descr) => vm.call_get_descriptor(descr, obj).unwrap_or_else(|| {
+        Some(descr) => vm.call_get_descriptor(descr, obj).unwrap_or_else(|_| {
             Err(vm.new_type_error(format!(
                 "this __dict__ descriptor does not support '{}' objects",
                 cls.name
diff --git a/vm/src/function.rs b/vm/src/function.rs
index 6428fd18d..42626593f 100644
--- a/vm/src/function.rs
+++ b/vm/src/function.rs
@@ -26,6 +26,11 @@ where
     }
 }
 
+macro_rules! count {
+    () => (0usize);
+    ( $x:tt $($xs:tt)* ) => (1usize + count!($($xs)*));
+}
+
 // A tuple of values that each implement `IntoPyObject` represents a sequence of
 // arguments that can be bound and passed to a built-in function.
 macro_rules! into_func_args_from_tuple {
@@ -37,7 +42,9 @@ macro_rules! into_func_args_from_tuple {
             #[inline]
             fn into_args(self, vm: &VirtualMachine) -> FuncArgs {
                 let ($($n,)*) = self;
-                vec![$($n.into_pyobject(vm),)*].into()
+                let mut result = Vec::with_capacity(count!($($n,)*) + 1);
+                $(result.push($n.into_pyobject(vm), );)*
+                result.into()
             }
         }
     };
diff --git a/vm/src/vm.rs b/vm/src/vm.rs
index 69b90f92b..7ab652421 100644
--- a/vm/src/vm.rs
+++ b/vm/src/vm.rs
@@ -944,19 +944,25 @@ impl VirtualMachine {
         descr: PyObjectRef,
         obj: Option<PyObjectRef>,
         cls: Option<PyObjectRef>,
-    ) -> Option<PyResult> {
+    ) -> Result<PyResult, PyObjectRef> {
         let descr_get = descr.class().mro_find_map(|cls| cls.slots.descr_get.load());
-        descr_get.map(|descr_get| descr_get(descr, obj, cls, self))
+        match descr_get {
+            Some(descr_get) => Ok(descr_get(descr, obj, cls, self)),
+            None => Err(descr),
+        }
     }
 
-    pub fn call_get_descriptor(&self, descr: PyObjectRef, obj: PyObjectRef) -> Option<PyResult> {
+    pub fn call_get_descriptor(
+        &self,
+        descr: PyObjectRef,
+        obj: PyObjectRef,
+    ) -> Result<PyResult, PyObjectRef> {
         let cls = obj.clone_class().into_object();
         self.call_get_descriptor_specific(descr, Some(obj), Some(cls))
     }
 
     pub fn call_if_get_descriptor(&self, attr: PyObjectRef, obj: PyObjectRef) -> PyResult {
-        self.call_get_descriptor(attr.clone(), obj)
-            .unwrap_or(Ok(attr))
+        self.call_get_descriptor(attr, obj).unwrap_or_else(Ok)
     }
 
     pub fn call_method<T>(&self, obj: &PyObjectRef, method_name: &str, args: T) -> PyResult
@@ -1257,7 +1263,7 @@ impl VirtualMachine {
 
         if let Some(ref attr) = cls_attr {
             if attr.class().has_attr("__set__") {
-                if let Some(r) = self.call_get_descriptor(attr.clone(), obj.clone()) {
+                if let Ok(r) = self.call_get_descriptor(attr.clone(), obj.clone()) {
                     return r.map(Some);
                 }
             }