diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 0bddd7a990699..cacbd54b6c246 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -178,6 +178,8 @@ pub struct BTreeMap<
length: usize,
/// `ManuallyDrop` to control drop order (needs to be dropped after all the nodes).
pub(super) alloc: ManuallyDrop<A>,
+ // For dropck; the `Box` avoids making the `Unpin` impl more strict than before
+ _marker: PhantomData<crate::boxed::Box<(K, V)>>,
}
#[stable(feature = "btree_drop", since = "1.7.0")]
@@ -187,6 +189,19 @@ unsafe impl<#[may_dangle] K, #[may_dangle] V, A: Allocator + Clone> Drop for BTr
}
}
+// FIXME: This implementation is "wrong", but changing it would be a breaking change.
+// (The bounds of the automatic `UnwindSafe` implementation have been like this since Rust 1.50.)
+// Maybe we can fix it nonetheless with a crater run, or if the `UnwindSafe`
+// traits are deprecated, or disarmed (no longer causing hard errors) in the future.
+#[stable(feature = "btree_unwindsafe", since = "1.64.0")]
+impl<K, V, A: Allocator + Clone> core::panic::UnwindSafe for BTreeMap<K, V, A>
+where
+ A: core::panic::UnwindSafe,
+ K: core::panic::RefUnwindSafe,
+ V: core::panic::RefUnwindSafe,
+{
+}
+
#[stable(feature = "rust1", since = "1.0.0")]
impl<K: Clone, V: Clone, A: Allocator + Clone> Clone for BTreeMap<K, V, A> {
fn clone(&self) -> BTreeMap<K, V, A> {
@@ -204,6 +219,7 @@ impl<K: Clone, V: Clone, A: Allocator + Clone> Clone for BTreeMap<K, V, A> {
root: Some(Root::new(alloc.clone())),
length: 0,
alloc: ManuallyDrop::new(alloc),
+ _marker: PhantomData,
};
{
@@ -567,7 +583,7 @@ impl<K, V> BTreeMap<K, V> {
#[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
#[must_use]
pub const fn new() -> BTreeMap<K, V> {
- BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(Global) }
+ BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(Global), _marker: PhantomData }
}
}
@@ -593,6 +609,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
root: mem::replace(&mut self.root, None),
length: mem::replace(&mut self.length, 0),
alloc: self.alloc.clone(),
+ _marker: PhantomData,
});
}
@@ -615,7 +632,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
/// ```
#[unstable(feature = "btreemap_alloc", issue = "32838")]
pub fn new_in(alloc: A) -> BTreeMap<K, V, A> {
- BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(alloc) }
+ BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(alloc), _marker: PhantomData }
}
}
@@ -1320,7 +1337,12 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
let (new_left_len, right_len) = Root::calc_split_length(total_num, &left_root, &right_root);
self.length = new_left_len;
- BTreeMap { root: Some(right_root), length: right_len, alloc: self.alloc.clone() }
+ BTreeMap {
+ root: Some(right_root),
+ length: right_len,
+ alloc: self.alloc.clone(),
+ _marker: PhantomData,
+ }
}
/// Creates an iterator that visits all elements (key-value pairs) in
@@ -1445,7 +1467,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
let mut root = Root::new(alloc.clone());
let mut length = 0;
root.bulk_push(DedupSortedIter::new(iter.into_iter()), &mut length, alloc.clone());
- BTreeMap { root: Some(root), length, alloc: ManuallyDrop::new(alloc) }
+ BTreeMap { root: Some(root), length, alloc: ManuallyDrop::new(alloc), _marker: PhantomData }
}
}
diff --git a/src/test/ui/btreemap/btreemap_dropck.rs b/src/test/ui/btreemap/btreemap_dropck.rs
new file mode 100644
index 0000000000000..c58727df30cae
--- /dev/null
+++ b/src/test/ui/btreemap/btreemap_dropck.rs
@@ -0,0 +1,16 @@
+struct PrintOnDrop<'a>(&'a str);
+
+impl Drop for PrintOnDrop<'_> {
+ fn drop(&mut self) {
+ println!("printint: {}", self.0);
+ }
+}
+
+use std::collections::BTreeMap;
+use std::iter::FromIterator;
+
+fn main() {
+ let s = String::from("Hello World!");
+ let _map = BTreeMap::from_iter([((), PrintOnDrop(&s))]);
+ drop(s); //~ ERROR cannot move out of `s` because it is borrowed
+}
diff --git a/src/test/ui/btreemap/btreemap_dropck.stderr b/src/test/ui/btreemap/btreemap_dropck.stderr
new file mode 100644
index 0000000000000..e953e7ae82bb8
--- /dev/null
+++ b/src/test/ui/btreemap/btreemap_dropck.stderr
@@ -0,0 +1,13 @@
+error[E0505]: cannot move out of `s` because it is borrowed
+ --> $DIR/btreemap_dropck.rs:15:10
+ |
+LL | let _map = BTreeMap::from_iter([((), PrintOnDrop(&s))]);
+ | -- borrow of `s` occurs here
+LL | drop(s);
+ | ^ move out of `s` occurs here
+LL | }
+ | - borrow might be used here, when `_map` is dropped and runs the `Drop` code for type `BTreeMap`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0505`.
diff --git a/src/test/ui/issues/issue-72554.rs b/src/test/ui/issues/issue-72554.rs
index 47aca05d7786f..7287639c61dde 100644
--- a/src/test/ui/issues/issue-72554.rs
+++ b/src/test/ui/issues/issue-72554.rs
@@ -1,10 +1,13 @@
use std::collections::BTreeSet;
#[derive(Hash)]
-pub enum ElemDerived { //~ ERROR recursive type `ElemDerived` has infinite size
+pub enum ElemDerived {
+ //~^ ERROR recursive type `ElemDerived` has infinite size
+ //~| ERROR cycle detected when computing drop-check constraints for `ElemDerived`
A(ElemDerived)
}
+
pub enum Elem {
Derived(ElemDerived)
}
diff --git a/src/test/ui/issues/issue-72554.stderr b/src/test/ui/issues/issue-72554.stderr
index a6e44be636a43..3e5adcae133ca 100644
--- a/src/test/ui/issues/issue-72554.stderr
+++ b/src/test/ui/issues/issue-72554.stderr
@@ -3,6 +3,7 @@ error[E0072]: recursive type `ElemDerived` has infinite size
|
LL | pub enum ElemDerived {
| ^^^^^^^^^^^^^^^^^^^^ recursive type has infinite size
+...
LL | A(ElemDerived)
| ----------- recursive without indirection
|
@@ -11,6 +12,20 @@ help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `ElemDerived
LL | A(Box<ElemDerived>)
| ++++ +
-error: aborting due to previous error
+error[E0391]: cycle detected when computing drop-check constraints for `ElemDerived`
+ --> $DIR/issue-72554.rs:4:1
+ |
+LL | pub enum ElemDerived {
+ | ^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: ...which immediately requires computing drop-check constraints for `ElemDerived` again
+note: cycle used when computing drop-check constraints for `Elem`
+ --> $DIR/issue-72554.rs:11:1
+ |
+LL | pub enum Elem {
+ | ^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
-For more information about this error, try `rustc --explain E0072`.
+Some errors have detailed explanations: E0072, E0391.
+For more information about an error, try `rustc --explain E0072`.