From 490c638b4f168535c4efcca04c92366ee36ea727 Mon Sep 17 00:00:00 2001
From: Noah <33094578+coolreader18@users.noreply.github.com>
Date: Tue, 9 Jun 2020 15:47:27 -0500
Subject: [PATCH] Add size_hint() to PyIterator

---
 vm/src/pyobject.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
index 5d43fdf5c..4f82b554d 100644
--- a/vm/src/pyobject.rs
+++ b/vm/src/pyobject.rs
@@ -980,9 +980,12 @@ impl<T> PyIterable<T> {
             },
         )?;
 
+        let lenhint = objiter::length_hint(vm, iter_obj.clone())?;
+
         Ok(PyIterator {
             vm,
             obj: iter_obj,
+            lenhint,
             _item: std::marker::PhantomData,
         })
     }
@@ -991,6 +994,7 @@ impl<T> PyIterable<T> {
 pub struct PyIterator<'a, T> {
     vm: &'a VirtualMachine,
     obj: PyObjectRef,
+    lenhint: Option<usize>,
     _item: std::marker::PhantomData<T>,
 }
 
@@ -1012,6 +1016,10 @@ where
             }
         }
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (self.lenhint.unwrap_or(0), self.lenhint)
+    }
 }
 
 impl<T> TryFromObject for PyIterable<T>