Rename `~const Drop` to `~const Destruct`

6 files changed, 89 insertions, 48 deletions

diff --git a/library/core/src/bool.rs b/library/core/src/bool.rs
index d5119d0b7c3..a13593a539d 100644
--- a/library/core/src/bool.rs
+++ b/library/core/src/bool.rs
@@ -1,5 +1,7 @@
 //! impl bool {}
 
+use crate::marker::Destruct;
+
 #[lang = "bool"]
 impl bool {
     /// Returns `Some(t)` if the `bool` is [`true`](../std/keyword.true.html),
@@ -16,9 +18,10 @@ impl bool {
     #[unstable(feature = "bool_to_option", issue = "80967")]
     #[rustc_const_unstable(feature = "const_bool_to_option", issue = "91917")]
     #[inline]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn then_some<T>(self, t: T) -> Option<T>
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         if self { Some(t) } else { None }
     }
@@ -35,10 +38,11 @@ impl bool {
     #[stable(feature = "lazy_bool_to_option", since = "1.50.0")]
     #[rustc_const_unstable(feature = "const_bool_to_option", issue = "91917")]
     #[inline]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn then<T, F>(self, f: F) -> Option<T>
     where
         F: ~const FnOnce() -> T,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         if self { Some(f()) } else { None }
     }
diff --git a/library/core/src/clone.rs b/library/core/src/clone.rs
index 1912694412b..cfdc51c71ee 100644
--- a/library/core/src/clone.rs
+++ b/library/core/src/clone.rs
@@ -36,6 +36,8 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
+use crate::marker::Destruct;
+
 /// A common trait for the ability to explicitly duplicate an object.
 ///
 /// Differs from [`Copy`] in that [`Copy`] is implicit and an inexpensive bit-wise copy, while
@@ -128,9 +130,10 @@ pub trait Clone: Sized {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[default_method_body_is_const]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     fn clone_from(&mut self, source: &Self)
     where
-        Self: ~const Drop,
+        Self: ~const Drop + ~const Destruct,
     {
         *self = source.clone()
     }
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 1d457c2b7d5..22c6c1cd868 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -54,7 +54,7 @@
 )]
 #![allow(missing_docs)]
 
-use crate::marker::DiscriminantKind;
+use crate::marker::{Destruct, DiscriminantKind};
 use crate::mem;
 
 // These imports are used for simplifying intra-doc links
@@ -2353,6 +2353,7 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
 #[rustc_const_unstable(feature = "const_eval_select", issue = "none")]
 #[lang = "const_eval_select"]
 #[rustc_do_not_const_check]
+#[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
 pub const unsafe fn const_eval_select<ARG, F, G, RET>(
     arg: ARG,
     _called_in_const: F,
@@ -2360,7 +2361,7 @@ pub const unsafe fn const_eval_select<ARG, F, G, RET>(
 ) -> RET
 where
     F: ~const FnOnce<ARG, Output = RET>,
-    G: FnOnce<ARG, Output = RET> + ~const Drop,
+    G: FnOnce<ARG, Output = RET> + ~const Drop + ~const Destruct,
 {
     called_at_rt.call_once(arg)
 }
@@ -2372,6 +2373,7 @@ where
 )]
 #[rustc_const_unstable(feature = "const_eval_select", issue = "none")]
 #[lang = "const_eval_select_ct"]
+#[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
 pub const unsafe fn const_eval_select_ct<ARG, F, G, RET>(
     arg: ARG,
     called_in_const: F,
@@ -2379,7 +2381,7 @@ pub const unsafe fn const_eval_select_ct<ARG, F, G, RET>(
 ) -> RET
 where
     F: ~const FnOnce<ARG, Output = RET>,
-    G: FnOnce<ARG, Output = RET> + ~const Drop,
+    G: FnOnce<ARG, Output = RET> + ~const Drop + ~const Destruct,
 {
     called_in_const.call_once(arg)
 }
diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs
index 44d388fb7a3..6b9d6253e42 100644
--- a/library/core/src/marker.rs
+++ b/library/core/src/marker.rs
@@ -794,10 +794,19 @@ impl<T: ?Sized> Unpin for *mut T {}
 
 /// A marker for types that can be dropped.
 ///
-/// The compiler logic for this trait is currently unimplemented.
+/// This should be used for `~const` bounds,
+/// as non-const bounds will always hold for every type.
 #[unstable(feature = "const_trait_impl", issue = "67792")]
-#[cfg_attr(not(bootstrap), lang = "destructible")]
-pub trait Destructible {}
+#[cfg_attr(not(bootstrap), lang = "destruct")]
+#[cfg_attr(
+    not(bootstrap),
+    rustc_on_unimplemented(message = "can't drop `{Self}`", append_const_msg,)
+)]
+pub trait Destruct {}
+
+#[cfg(bootstrap)]
+#[unstable(feature = "const_trait_impl", issue = "67792")]
+impl<T: ?Sized> const Destruct for T {}
 
 /// Implementations of `Copy` for primitive types.
 ///
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index bcba18a4a3e..acab8de8c70 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -503,6 +503,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 use crate::iter::{self, FromIterator, FusedIterator, TrustedLen};
+use crate::marker::Destruct;
 use crate::panicking::{panic, panic_str};
 use crate::pin::Pin;
 use crate::{
@@ -772,9 +773,10 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn unwrap_or(self, default: T) -> T
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         match self {
             Some(x) => x,
@@ -794,10 +796,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn unwrap_or_else<F>(self, f: F) -> T
     where
         F: ~const FnOnce() -> T,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Some(x) => x,
@@ -899,10 +902,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn map<U, F>(self, f: F) -> Option<U>
     where
         F: ~const FnOnce(T) -> U,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Some(x) => Some(f(x)),
@@ -928,10 +932,11 @@ impl<T> Option<T> {
     #[inline]
     #[unstable(feature = "result_option_inspect", issue = "91345")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn inspect<F>(self, f: F) -> Self
     where
         F: ~const FnOnce(&T),
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         if let Some(ref x) = self {
             f(x);
@@ -961,11 +966,12 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn map_or<U, F>(self, default: U, f: F) -> U
     where
         F: ~const FnOnce(T) -> U,
-        F: ~const Drop,
-        U: ~const Drop,
+        F: ~const Drop + ~const Destruct,
+        U: ~const Drop + ~const Destruct,
     {
         match self {
             Some(t) => f(t),
@@ -990,12 +996,13 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn map_or_else<U, D, F>(self, default: D, f: F) -> U
     where
         D: ~const FnOnce() -> U,
-        D: ~const Drop,
+        D: ~const Drop + ~const Destruct,
         F: ~const FnOnce(T) -> U,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Some(t) => f(t),
@@ -1027,9 +1034,10 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn ok_or<E>(self, err: E) -> Result<T, E>
     where
-        E: ~const Drop,
+        E: ~const Drop + ~const Destruct,
     {
         match self {
             Some(v) => Ok(v),
@@ -1056,10 +1064,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn ok_or_else<E, F>(self, err: F) -> Result<T, E>
     where
         F: ~const FnOnce() -> E,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Some(v) => Ok(v),
@@ -1190,10 +1199,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn and<U>(self, optb: Option<U>) -> Option<U>
     where
-        T: ~const Drop,
-        U: ~const Drop,
+        T: ~const Drop + ~const Destruct,
+        U: ~const Drop + ~const Destruct,
     {
         match self {
             Some(_) => optb,
@@ -1232,10 +1242,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn and_then<U, F>(self, f: F) -> Option<U>
     where
         F: ~const FnOnce(T) -> Option<U>,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Some(x) => f(x),
@@ -1270,11 +1281,12 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "option_filter", since = "1.27.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn filter<P>(self, predicate: P) -> Self
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
         P: ~const FnOnce(&T) -> bool,
-        P: ~const Drop,
+        P: ~const Drop + ~const Destruct,
     {
         if let Some(x) = self {
             if predicate(&x) {
@@ -1314,9 +1326,10 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn or(self, optb: Option<T>) -> Option<T>
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         match self {
             Some(x) => Some(x),
@@ -1340,10 +1353,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn or_else<F>(self, f: F) -> Option<T>
     where
         F: ~const FnOnce() -> Option<T>,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Some(x) => Some(x),
@@ -1375,9 +1389,10 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "option_xor", since = "1.37.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn xor(self, optb: Option<T>) -> Option<T>
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         match (self, optb) {
             (Some(a), None) => Some(a),
@@ -1413,9 +1428,10 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "option_insert", since = "1.53.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn insert(&mut self, value: T) -> &mut T
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         *self = Some(value);
 
@@ -1446,9 +1462,10 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "option_entry", since = "1.20.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn get_or_insert(&mut self, value: T) -> &mut T
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         if let None = *self {
             *self = Some(value);
@@ -1513,10 +1530,11 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "option_entry", since = "1.20.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn get_or_insert_with<F>(&mut self, f: F) -> &mut T
     where
         F: ~const FnOnce() -> T,
-        F: ~const Drop,
+        F: ~const Drop + ~const Destruct,
     {
         if let None = *self {
             // the compiler isn't smart enough to know that we are not dropping a `T`
@@ -1627,10 +1645,11 @@ impl<T> Option<T> {
     /// ```
     #[stable(feature = "option_zip_option", since = "1.46.0")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn zip<U>(self, other: Option<U>) -> Option<(T, U)>
     where
-        T: ~const Drop,
-        U: ~const Drop,
+        T: ~const Drop + ~const Destruct,
+        U: ~const Drop + ~const Destruct,
     {
         match (self, other) {
             (Some(a), Some(b)) => Some((a, b)),
@@ -1668,12 +1687,13 @@ impl<T> Option<T> {
     /// ```
     #[unstable(feature = "option_zip", issue = "70086")]
     #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn zip_with<U, F, R>(self, other: Option<U>, f: F) -> Option<R>
     where
         F: ~const FnOnce(T, U) -> R,
-        F: ~const Drop,
-        T: ~const Drop,
-        U: ~const Drop,
+        F: ~const Drop + ~const Destruct,
+        T: ~const Drop + ~const Destruct,
+        U: ~const Drop + ~const Destruct,
     {
         match (self, other) {
             (Some(a), Some(b)) => Some(f(a, b)),
@@ -1860,9 +1880,10 @@ const fn expect_failed(msg: &str) -> ! {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
+#[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
 impl<T> const Clone for Option<T>
 where
-    T: ~const Clone + ~const Drop,
+    T: ~const Clone + ~const Drop + ~const Destruct,
 {
     #[inline]
     fn clone(&self) -> Self {
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 9a243cbc3a2..afd0c857229 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -490,6 +490,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 use crate::iter::{self, FromIterator, FusedIterator, TrustedLen};
+use crate::marker::Destruct;
 use crate::ops::{self, ControlFlow, Deref, DerefMut};
 use crate::{convert, fmt, hint};
 
@@ -635,7 +636,7 @@ impl<T, E> Result<T, E> {
     #[rustc_const_unstable(feature = "const_result_drop", issue = "92384")]
     pub const fn ok(self) -> Option<T>
     where
-        E: ~const Drop,
+        E: ~const Drop + ~const Destruct,
     {
         match self {
             Ok(x) => Some(x),
@@ -666,7 +667,7 @@ impl<T, E> Result<T, E> {
     #[rustc_const_unstable(feature = "const_result_drop", issue = "92384")]
     pub const fn err(self) -> Option<E>
     where
-        T: ~const Drop,
+        T: ~const Drop + ~const Destruct,
     {
         match self {
             // FIXME: ~const Drop doesn't quite work right yet
@@ -1282,9 +1283,9 @@ impl<T, E> Result<T, E> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn and<U>(self, res: Result<U, E>) -> Result<U, E>
     where
-        T: ~const Drop,
-        U: ~const Drop,
-        E: ~const Drop,
+        T: ~const Drop + ~const Destruct,
+        U: ~const Drop + ~const Destruct,
+        E: ~const Drop + ~const Destruct,
     {
         match self {
             // FIXME: ~const Drop doesn't quite work right yet
@@ -1367,9 +1368,9 @@ impl<T, E> Result<T, E> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn or<F>(self, res: Result<T, F>) -> Result<T, F>
     where
-        T: ~const Drop,
-        E: ~const Drop,
-        F: ~const Drop,
+        T: ~const Drop + ~const Destruct,
+        E: ~const Drop + ~const Destruct,
+        F: ~const Drop + ~const Destruct,
     {
         match self {
             Ok(v) => Ok(v),
@@ -1431,8 +1432,8 @@ impl<T, E> Result<T, E> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn unwrap_or(self, default: T) -> T
     where
-        T: ~const Drop,
-        E: ~const Drop,
+        T: ~const Drop + ~const Destruct,
+        E: ~const Drop + ~const Destruct,
     {
         match self {
             Ok(t) => t,
@@ -1802,10 +1803,11 @@ fn unwrap_failed<T>(_msg: &str, _error: &T) -> ! {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
+#[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
 impl<T, E> const Clone for Result<T, E>
 where
-    T: ~const Clone + ~const Drop,
-    E: ~const Clone + ~const Drop,
+    T: ~const Clone + ~const Drop + ~const Destruct,
+    E: ~const Clone + ~const Drop + ~const Destruct,
 {
     #[inline]
     fn clone(&self) -> Self {