Auto merge of rust-lang#75244 - Manishearth:rollup-dzfyjva, r=Manishearth

Rollup of 4 pull requests

Successful merges:

 - rust-lang#74774 (adds [*mut|*const] ptr::set_ptr_value)
 - rust-lang#75079 (Disallow linking to items with a mismatched disambiguator)
 - rust-lang#75203 (Make `IntoIterator` lifetime bounds of `&BTreeMap` match with `&HashMap` )
 - rust-lang#75227 (Fix ICE when using asm! on an unsupported architecture)

Failed merges:

r? @ghost

Author: bors

alloc/src/collections/btree/map.rs

@@ -1294,7 +1294,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: 'a, V: 'a> IntoIterator for &'a BTreeMap<K, V> {
+impl<'a, K, V> IntoIterator for &'a BTreeMap<K, V> {
     type Item = (&'a K, &'a V);
     type IntoIter = Iter<'a, K, V>;
 
@@ -1363,7 +1363,7 @@ impl<K, V> Clone for Iter<'_, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: 'a, V: 'a> IntoIterator for &'a mut BTreeMap<K, V> {
+impl<'a, K, V> IntoIterator for &'a mut BTreeMap<K, V> {
     type Item = (&'a K, &'a mut V);
     type IntoIter = IterMut<'a, K, V>;
 

core/src/ptr/const_ptr.rs

@@ -656,6 +656,38 @@ impl<T: ?Sized> *const T {
         self.wrapping_offset((count as isize).wrapping_neg())
     }
 
+    /// Sets the pointer value to `ptr`.
+    ///
+    /// In case `self` is a (fat) pointer to an unsized type, this operation
+    /// will only affect the pointer part, whereas for (thin) pointers to
+    /// sized types, this has the same effect as a simple assignment.
+    ///
+    /// # Examples
+    ///
+    /// This function is primarily useful for allowing byte-wise pointer
+    /// arithmetic on potentially fat pointers:
+    ///
+    /// ```
+    /// #![feature(set_ptr_value)]
+    /// # use core::fmt::Debug;
+    /// let arr: [i32; 3] = [1, 2, 3];
+    /// let mut ptr = &arr[0] as *const dyn Debug;
+    /// let thin = ptr as *const u8;
+    /// ptr = ptr.set_ptr_value(unsafe { thin.add(8).cast() });
+    /// assert_eq!(unsafe { *(ptr as *const i32) }, 3);
+    /// ```
+    #[unstable(feature = "set_ptr_value", issue = "75091")]
+    #[inline]
+    pub fn set_ptr_value(mut self, val: *const ()) -> Self {
+        let thin = &mut self as *mut *const T as *mut *const ();
+        // SAFETY: In case of a thin pointer, this operations is identical
+        // to a simple assignment. In case of a fat pointer, with the current
+        // fat pointer layout implementation, the first field of such a
+        // pointer is always the data pointer, which is likewise assigned.
+        unsafe { *thin = val };
+        self
+    }
+
     /// Reads the value from `self` without moving it. This leaves the
     /// memory in `self` unchanged.
     ///

core/src/ptr/mut_ptr.rs

@@ -712,6 +712,38 @@ impl<T: ?Sized> *mut T {
         self.wrapping_offset((count as isize).wrapping_neg())
     }
 
+    /// Sets the pointer value to `ptr`.
+    ///
+    /// In case `self` is a (fat) pointer to an unsized type, this operation
+    /// will only affect the pointer part, whereas for (thin) pointers to
+    /// sized types, this has the same effect as a simple assignment.
+    ///
+    /// # Examples
+    ///
+    /// This function is primarily useful for allowing byte-wise pointer
+    /// arithmetic on potentially fat pointers:
+    ///
+    /// ```
+    /// #![feature(set_ptr_value)]
+    /// # use core::fmt::Debug;
+    /// let mut arr: [i32; 3] = [1, 2, 3];
+    /// let mut ptr = &mut arr[0] as *mut dyn Debug;
+    /// let thin = ptr as *mut u8;
+    /// ptr = ptr.set_ptr_value(unsafe { thin.add(8).cast() });
+    /// assert_eq!(unsafe { *(ptr as *mut i32) }, 3);
+    /// ```
+    #[unstable(feature = "set_ptr_value", issue = "75091")]
+    #[inline]
+    pub fn set_ptr_value(mut self, val: *mut ()) -> Self {
+        let thin = &mut self as *mut *mut T as *mut *mut ();
+        // SAFETY: In case of a thin pointer, this operations is identical
+        // to a simple assignment. In case of a fat pointer, with the current
+        // fat pointer layout implementation, the first field of such a
+        // pointer is always the data pointer, which is likewise assigned.
+        unsafe { *thin = val };
+        self
+    }
+
     /// Reads the value from `self` without moving it. This leaves the
     /// memory in `self` unchanged.
     ///