Tracking Issue for #![feature(ptr_cast_slice)] #149103

Feature gate: #![feature(ptr_cast_slice)]

This is a tracking issue for rust-lang/libs-team#693

This feature adds method calls on raw pointers that call into the respective ptr::slice_from_raw_parts{_mut} method for the types *const T, *mut T and NonNull<T> to make using raw pointers more ergonomic in Rust by supporting postfix method chain syntax while creating slices.

Public API

// core::ptr::const_ptr
impl<T> *const T {
    pub const fn cast_slice(self, len: usize) -> *const [T];
}

// core::ptr::mut_ptr
impl<T> *mut T {
    pub const fn cast_slice(self, len: usize) -> *mut [T];
}

// core::ptr::non_null
impl<T> NonNull<T> {
    pub const fn cast_slice(self, len: usize) -> NonNull<[T]>;
}

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

• ACP: rust-lang/libs-team#693
• Implementation: Implement cast_slice for raw pointer types #149110
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• the inference problem
  • infers: let null10: *const [u8] = ptr::slice_from_raw_parts(ptr::null(), 10);
  • does not infer: let null10: *const [u8] = ptr::null().cast_slice(10);
  • deemed okay to have Tracking Issue for #![feature(ptr_cast_slice)] #149103 (comment)