Auto merge of #188 - mbrubeck:iter, r=Amanieu

Implement FusedIterator and size_hint for DrainFilter

None

Author: bors

src/map.rs

@@ -846,7 +846,7 @@ where
             Some(item) => unsafe {
                 let &(ref key, ref value) = item.as_ref();
                 Some((key, value))
-            }
+            },
             None => None,
         }
     }
@@ -886,7 +886,7 @@ where
             Some(item) => unsafe {
                 let &mut (ref key, ref mut value) = item.as_mut();
                 Some((key, value))
-            }
+            },
             None => None,
         }
     }
@@ -1390,8 +1390,15 @@ where
     fn next(&mut self) -> Option<Self::Item> {
         self.inner.next(&mut self.f)
     }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (0, self.inner.iter.size_hint().1)
+    }
 }
 
+impl<K, V, F> FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
+
 /// Portions of `DrainFilter` shared with `set::DrainFilter`
 pub(super) struct DrainFilterInner<'a, K, V> {
     pub iter: RawIter<(K, V)>,
@@ -1585,7 +1592,7 @@ impl<'a, K, V, S> RawEntryBuilder<'a, K, V, S> {
             Some(item) => unsafe {
                 let &(ref key, ref value) = item.as_ref();
                 Some((key, value))
-            }
+            },
             None => None,
         }
     }
@@ -2055,7 +2062,7 @@ impl<'a, K, V> Iterator for Iter<'a, K, V> {
             Some(x) => unsafe {
                 let r = x.as_ref();
                 Some((&r.0, &r.1))
-            }
+            },
             None => None,
         }
     }
@@ -2083,7 +2090,7 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
             Some(x) => unsafe {
                 let r = x.as_mut();
                 Some((&r.0, &mut r.1))
-            }
+            },
             None => None,
         }
     }

src/raw/mod.rs

@@ -406,7 +406,7 @@ impl<T> RawTable<T> {
         // Avoid `Option::ok_or_else` because it bloats LLVM IR.
         let (layout, ctrl_offset) = match calculate_layout::<T>(buckets) {
             Some(lco) => lco,
-            None => return Err(fallability.capacity_overflow())
+            None => return Err(fallability.capacity_overflow()),
         };
         let ptr = match NonNull::new(alloc(layout)) {
             Some(ptr) => ptr,
@@ -688,7 +688,10 @@ impl<T> RawTable<T> {
                 *self = Self::with_capacity(min_size)
             } else {
                 // Avoid `Result::unwrap_or_else` because it bloats LLVM IR.
-                if self.resize(min_size, hasher, Fallibility::Infallible).is_err() {
+                if self
+                    .resize(min_size, hasher, Fallibility::Infallible)
+                    .is_err()
+                {
                     unsafe { hint::unreachable_unchecked() }
                 }
             }
@@ -701,7 +704,10 @@ impl<T> RawTable<T> {
     pub fn reserve(&mut self, additional: usize, hasher: impl Fn(&T) -> u64) {
         if additional > self.growth_left {
             // Avoid `Result::unwrap_or_else` because it bloats LLVM IR.
-            if self.reserve_rehash(additional, hasher, Fallibility::Infallible).is_err() {
+            if self
+                .reserve_rehash(additional, hasher, Fallibility::Infallible)
+                .is_err()
+            {
                 unsafe { hint::unreachable_unchecked() }
             }
         }
@@ -1114,7 +1120,7 @@ impl<T: Clone> Clone for RawTable<T> {
                     match Self::new_uninitialized(self.buckets(), Fallibility::Infallible) {
                         Ok(table) => table,
                         Err(_) => hint::unreachable_unchecked(),
-                    }
+                    },
                 );
 
                 new_table.clone_from_spec(self, |new_table| {
@@ -1151,7 +1157,7 @@ impl<T: Clone> Clone for RawTable<T> {
                         match Self::new_uninitialized(source.buckets(), Fallibility::Infallible) {
                             Ok(table) => table,
                             Err(_) => hint::unreachable_unchecked(),
-                        }
+                        },
                     );
                 }
 

src/set.rs

@@ -1462,8 +1462,15 @@ where
         let (k, _) = self.inner.next(&mut |k, _| f(k))?;
         Some(k)
     }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (0, self.inner.iter.size_hint().1)
+    }
 }
 
+impl<K, F> FusedIterator for DrainFilter<'_, K, F> where F: FnMut(&K) -> bool {}
+
 impl<T, S> Clone for Intersection<'_, T, S> {
     #[cfg_attr(feature = "inline-more", inline)]
     fn clone(&self) -> Self {