Auto merge of #67485 - Centril:rollup-gt0opvr, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #67059 (Fix too restrictive checks on Drop impls)
 - #67355 (Merge `ast::Mutability` and `mir::Mutability`)
 - #67393 (Enable opting out of specific default LLVM arguments.)
 - #67422 (Cleanup err codes)
 - #67462 (Make ptr::slice_from_raw_parts a const fn available under a feature flag)
 - #67467 (Test slice patterns more)
 - #67478 (Fix src/libcore/str/mod.rs doc comments)

Failed merges:

r? @ghost

Author: bors

src/libcore/ptr/mod.rs

@@ -259,7 +259,8 @@ pub(crate) struct FatPtr<T> {
 /// ```
 #[inline]
 #[unstable(feature = "slice_from_raw_parts", reason = "recently added", issue = "36925")]
-pub fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
+#[rustc_const_unstable(feature = "const_slice_from_raw_parts", issue = "67456")]
+pub const fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
     unsafe { Repr { raw: FatPtr { data, len } }.rust }
 }
 
@@ -275,7 +276,8 @@ pub fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
 /// [`from_raw_parts_mut`]: ../../std/slice/fn.from_raw_parts_mut.html
 #[inline]
 #[unstable(feature = "slice_from_raw_parts", reason = "recently added", issue = "36925")]
-pub fn slice_from_raw_parts_mut<T>(data: *mut T, len: usize) -> *mut [T] {
+#[rustc_const_unstable(feature = "const_slice_from_raw_parts", issue = "67456")]
+pub const fn slice_from_raw_parts_mut<T>(data: *mut T, len: usize) -> *mut [T] {
     unsafe { Repr { raw: FatPtr { data, len } }.rust_mut }
 }
 

src/libcore/str/mod.rs

@@ -2325,7 +2325,7 @@ impl str {
         i.get_mut(self)
     }
 
-    /// Returns a unchecked subslice of `str`.
+    /// Returns an unchecked subslice of `str`.
     ///
     /// This is the unchecked alternative to indexing the `str`.
     ///