Draft release notes for 1.93 #150760
Description
NOTE: Use the 📝 links to edit those that have a relnotes-tracking-issue,
and they will be updated when we regenerate the notes periodically (manually).
Version 1.93 (2026-01-22)
Language
- Add new
function_casts_as_integerlint
📝 - Add future-incompatibility warning for
...function parameters without a pattern outside ofexternblocks
📝 - Stabilize s390x
vectortarget feature andis_s390x_feature_detected!macro
📝 - Stabilize declaration of c-style variadic functions for the system ABI
📝 - Emit error when using some keyword as a
cfgpredicate
📝 - Future compat warning for repr(C) enums whose discriminant values do not fit into a c_int or c_uint
📝 - Forward-compatibility warning against ignoring repr(C) types as part of repr(transparent)
📝 - Stabilize
asm_cfg
📝 - Make deref_nullptr deny by default instead of warn
📝 - During const-evaluation, support copying pointers byte-for-byte
📝 - Add
const_item_interior_mutationslint to warn against calls which mutates an interior mutableconst-items
📝 - LUB coercions now correctly handle function item types, and functions with differing safeties
📝 - Allow
constitems that contain mutable references tostatic(which is very unsafe, but not always UB)
📝
Compiler
- Stabilize -Zno-jump-tables as -Cjump-tables=bool
📝 - Promote
riscv64a23-unknown-linux-gnuto Tier 2 (without host tools)
📝
Platform Support
Refer to Rust's platform support page
for more information on Rust's tiered platform support.
Libraries
- Allow the global allocator to use thread-local storage and std::thread::current()
📝 - Stabilize
char_max_len - Make
BTree::appendnot update existing keys when appending an entry which already exists
📝 - Don't require
T: RefUnwindSafeforvec::IntoIter<T>: UnwindSafe
📝
Stabilized APIs
String::into_raw_partsVec::into_raw_parts
📝<[T]>::as_array<[T]>::as_array_mut<*const [T]>::as_array<*mut [T]>::as_array_mut
📝VecDeque::pop_front_ifVecDeque::pop_back_if
📝Duration::from_nanos_u128
📝
These previously stable APIs are now stable in const contexts:
Cargo
- Enable CARGO_CFG_DEBUG_ASSERTIONS in build scripts based on profile
- feat(tree): Support long forms for --format variables
- clean: Add --workspace support
Rustdoc
- Remove
#![doc(document_private_items)]
📝 - Include attribute and derive macros in search filters for "macros"
📝 - Include extern crates in search filters for
import
📝 - validate usage of crate-level doc attributes. This means if any of
html_favicon_url,html_logo_url,html_playground_url,issue_tracker_base_url, orhtml_no_sourceeither has a missing value, an unexpected value, or a value of the wrong type, rustdoc will emit the deny-by-default lintrustdoc::invalid_doc_attributes.
📝
Compatibility Notes
- Introduce
pin_v2into the builtin attributes namespace
📝 - Update bundled musl to 1.2.5
📝 - On Emscripten, the unwinding ABI used when compiling with
panic=unwindwas changed from the JS exception handling ABI to the wasm exception handling ABI. If linking C/C++ object files with Rust objects,-fwasm-exceptionsmust be passed to the linker now. On nightly Rust, it is possible to get the old behavior with-Zwasm-emscripten-eh=false -Zbuild-std, but it will be removed in a future release.
📝 - Error when
testattribute is applied to structs
📝
Internal Changes
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.