Module nightly

Available on doc or test only.

Nightly features.

Legend:

• = not enabled / can’t be enabled
• · = enabled by non-specific feature (nightly_[next1|next2|later)
• a = enabled by non-specific feature (and depends on alloc)
• s = enabled by non-specific feature (and depends on std)
• F = enabled by some specific feature, shown afterwards.

See also

• https://doc.rust-lang.org/nightly/unstable-book/the-unstable-book.html
• https://github.com/rust-lang/rust/blob/master/library/core/src/lib.rs
• https://github.com/rust-lang/rust/blob/master/library/alloc/src/lib.rs
• https://github.com/rust-lang/rust/blob/master/library/std/src/lib.rs

1.86 will be stable on 2025-04-03 (nightly_stable_next1)

• https://github.com/rust-lang/rust/milestone/128

• 1.86: ·const_black_box
• 1.86: ·const_is_char_boundary · const_str_split_at
• 1.86: sconst_mut_cursor
• 1.86: ·float_next_up_down
• 1.86: get_disjoint_mut · get_many_mut (old name)
• 1.86: smap_many_mut
• 1.86: ·non_zero_count_ones
• 1.86: ·target_feature_11
• 1.86: ·trait_upcasting
• 1.86: avec_pop_if
• 1.86: iter::FromCoroutine

1.87 will be stable on 2025-05-15 (nightly_stable_next2)

• https://github.com/rust-lang/rust/milestone/130

• 1.87: ·const_slice_flatten
• 1.87: ·const_str_from_utf8
• 1.87: aextract_if
• 1.87: shash_extract_if
• 1.87: ·integer_sign_cast
• 1.87: sfile_lock
• 1.87: ·num_midpoint_signed
• 1.87: sos_str_display
• 1.87: ·ptr_sub_ptr · const_ptr_sub_ptr
• 1.87: ·unbounded_shifts
• 1.87: ·unsigned_is_multiple_of
• 1.87: Update to LLVM 20

… will be stable later (nightly_stable_later)

• 1.??: sanonymous_pipe
• 1.??: ·asm_goto
• 1.??: ·assert_matches
• 1.??: abox_uninit_write
• 1.??: ·cell_update
• 1.??: ·cfg_match
• 1.??: ·const_array_from_ref · const_slice_from_ref
• 1.??: aconst_vec_string_slice
• 1.??: ·const_swap_nonoverlapping
• 1.??: ·c_str_module
• 1.??: ·derive_coerce_pointee
• 1.??: flags for doctest cross compilation
• 1.??: ·impl_trait_in_assoc_type
• 1.??: ·integer_sign_cast
• 1.??: ·isqrt
• 1.??: ·let_chains
• 1.??: ·macro_metavar_expr
• 1.??: ·naked_functions
• 1.??: anew_zeroed_alloc
• 1.??: sonce_wait
• 1.??: ·slice_take split_off (new name)
• 1.??: ·unsafe_cell_from_mut

… may be stable even later

• 1.?? Fallocator_api = nightly_allocator
• 1.?? Fautodiff nightly_autodiff
• 1.?? Fbigint_helper_methods = nightly_bigint
• 1.?? box_into_inner
• 1.?? cfg(accessible(::path::to::thing))
• 1.?? cfg(version(..))
• 1.?? concat_bytes
• 1.?? concat_idents
• 1.?? const_async_blocks
• 1.?? const_closures
• 1.?? const_for (depends on const_trait_impl)
• 1.?? const_str_from_utf8
• 1.?? const_trait_impl
• 1.?? Fcoroutines = nightly_coro
• 1.?? Fdoc_cfg = nightly_doc
• 1.?? Fdoc_notable_trait = nightly_doc
• 1.?? Ff16|f128 = nightly_float
• 1.?? generic_atomic
• 1.?? integer_atomics
• 1.?? maybe_uninit_slice
• 1.?? mpmc_channel
• 1.?? panic_payload_as_str
• 1.?? passing unstable flags only on nightly
• 1.?? Fportable_simd = nightly_simd
• 1.?? slice_as_array
• 1.?? stdarch_x86_avx512
• 1.?? thread_local

Experimental features:

• local_waker
• offset_of_enum
• ptr_metadata - https://rust-lang.github.io/rfcs/2580-ptr-meta.html
• stmt_expr_attributes
• type_alias_impl_trait|impl_trait_in_assoc_type

Pitfalls

• const_evaluatable_unchecked

Meta tracking issues:

• arbitrary_self_types
  • stabilize arbitrary self types v2
• cargo config search
• const fn
• feature-metadata
• impl Trait
• int_roundings
• MaybeUninit methods for arrays
• num_midpoint
• Reproducible Build bugs
• unchecked_* on integers

Rust project Goals:

• https://rust-lang.github.io/rust-project-goals/
• const traits
• expanded const generics
• Linux building on stable
• next generation trait solver
• optimize clippy & linting
• stabilize cargo-script
• stabilize doc_cfg