Add #[may_dangle] to RawIntoIter

Also adds PhantomData<T> to RawTable and RawIntoIter
rust-lang · Mar 9, 2019 · 2678637 · 2678637
1 parent d73b3b2
commit 2678637
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Showing 3 changed files with 43 additions and 13 deletions.
diff --git a/src/external_trait_impls/rayon/raw.rs b/src/external_trait_impls/rayon/raw.rs
@@ -84,7 +84,7 @@ pub struct RawParDrain<'a, T> {
     // We don't use a &'a mut RawTable<T> because we want RawParDrain to be
     // covariant over T.
     table: NonNull<RawTable<T>>,
-    _marker: PhantomData<&'a RawTable<T>>,
+    marker: PhantomData<&'a RawTable<T>>,
 }
 
 unsafe impl<T> Send for RawParDrain<'_, T> {}
@@ -187,7 +187,7 @@ impl<T> RawTable<T> {
     pub fn par_drain(&mut self) -> RawParDrain<'_, T> {
         RawParDrain {
             table: NonNull::from(self),
-            _marker: PhantomData,
+            marker: PhantomData,
         }
     }
 }
diff --git a/src/map.rs b/src/map.rs
@@ -347,7 +347,7 @@ impl<K, V, S> HashMap<K, V, S> {
         unsafe {
             Iter {
                 inner: self.table.iter(),
-                _marker: PhantomData,
+                marker: PhantomData,
             }
         }
     }
@@ -381,7 +381,7 @@ impl<K, V, S> HashMap<K, V, S> {
         unsafe {
             IterMut {
                 inner: self.table.iter(),
-                _marker: PhantomData,
+                marker: PhantomData,
             }
         }
     }
@@ -1092,7 +1092,7 @@ where
 /// [`HashMap`]: struct.HashMap.html
 pub struct Iter<'a, K, V> {
     inner: RawIter<(K, V)>,
-    _marker: PhantomData<(&'a K, &'a V)>,
+    marker: PhantomData<(&'a K, &'a V)>,
 }
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
@@ -1101,7 +1101,7 @@ impl<K, V> Clone for Iter<'_, K, V> {
     fn clone(&self) -> Self {
         Iter {
             inner: self.inner.clone(),
-            _marker: PhantomData,
+            marker: PhantomData,
         }
     }
 }
@@ -1122,7 +1122,7 @@ impl<K: Debug, V: Debug> fmt::Debug for Iter<'_, K, V> {
 pub struct IterMut<'a, K, V> {
     inner: RawIter<(K, V)>,
     // To ensure invariance with respect to V
-    _marker: PhantomData<(&'a K, &'a mut V)>,
+    marker: PhantomData<(&'a K, &'a mut V)>,
 }
 
 impl<K, V> IterMut<'_, K, V> {
@@ -1131,7 +1131,7 @@ impl<K, V> IterMut<'_, K, V> {
     pub(super) fn iter(&self) -> Iter<'_, K, V> {
         Iter {
             inner: self.inner.clone(),
-            _marker: PhantomData,
+            marker: PhantomData,
         }
     }
 }
@@ -1153,7 +1153,7 @@ impl<K, V> IntoIter<K, V> {
     pub(super) fn iter(&self) -> Iter<'_, K, V> {
         Iter {
             inner: self.inner.iter(),
-            _marker: PhantomData,
+            marker: PhantomData,
         }
     }
 }
@@ -1229,7 +1229,7 @@ impl<K, V> Drain<'_, K, V> {
     pub(super) fn iter(&self) -> Iter<'_, K, V> {
         Iter {
             inner: self.inner.iter(),
-            _marker: PhantomData,
+            marker: PhantomData,
         }
     }
 }

diff --git a/src/raw/mod.rs b/src/raw/mod.rs
@@ -336,6 +336,9 @@ pub struct RawTable<T> {
 
     // Number of elements in the table, only really used by len()
     items: usize,
+
+    // Tell dropck that we own instances of T.
+    marker: PhantomData<T>,
 }
 
 impl<T> RawTable<T> {
@@ -352,6 +355,7 @@ impl<T> RawTable<T> {
             bucket_mask: 0,
             items: 0,
             growth_left: 0,
+            marker: PhantomData,
         }
     }
 
@@ -373,6 +377,7 @@ impl<T> RawTable<T> {
             bucket_mask: buckets - 1,
             items: 0,
             growth_left: bucket_mask_to_capacity(buckets - 1),
+            marker: PhantomData,
         })
     }
 
@@ -915,7 +920,7 @@ impl<T> RawTable<T> {
             iter: self.iter(),
             table: ManuallyDrop::new(mem::replace(self, Self::new())),
             orig_table: NonNull::from(self),
-            _marker: PhantomData,
+            marker: PhantomData,
         }
     }
 
@@ -1032,7 +1037,11 @@ impl<T> IntoIterator for RawTable<T> {
         unsafe {
             let iter = self.iter();
             let alloc = self.into_alloc();
-            RawIntoIter { iter, alloc }
+            RawIntoIter {
+                iter,
+                alloc,
+                marker: PhantomData,
+            }
         }
     }
 }
@@ -1225,6 +1234,7 @@ impl<T> FusedIterator for RawIter<T> {}
 pub struct RawIntoIter<T> {
     iter: RawIter<T>,
     alloc: Option<(NonNull<u8>, Layout)>,
+    marker: PhantomData<T>,
 }
 
 impl<T> RawIntoIter<T> {
@@ -1237,6 +1247,26 @@ impl<T> RawIntoIter<T> {
 unsafe impl<T> Send for RawIntoIter<T> where T: Send {}
 unsafe impl<T> Sync for RawIntoIter<T> where T: Sync {}
 
+#[cfg(feature = "nightly")]
+unsafe impl<#[may_dangle] T> Drop for RawIntoIter<T> {
+    #[inline]
+    fn drop(&mut self) {
+        unsafe {
+            // Drop all remaining elements
+            if mem::needs_drop::<T>() {
+                while let Some(item) = self.iter.next() {
+                    item.drop();
+                }
+            }
+
+            // Free the table
+            if let Some((ptr, layout)) = self.alloc {
+                dealloc(ptr.as_ptr(), layout);
+            }
+        }
+    }
+}
+#[cfg(not(feature = "nightly"))]
 impl<T> Drop for RawIntoIter<T> {
     #[inline]
     fn drop(&mut self) {
@@ -1285,7 +1315,7 @@ pub struct RawDrain<'a, T> {
 
     // We don't use a &'a mut RawTable<T> because we want RawDrain to be
     // covariant over T.
-    _marker: PhantomData<&'a RawTable<T>>,
+    marker: PhantomData<&'a RawTable<T>>,
 }
 
 impl<T> RawDrain<'_, T> {