rust-lang · JonathanBrouwer · Aug 5, 2026 · Aug 7, 2026 · Aug 10, 2026 · Aug 6, 2026
diff --git a/RELEASES.md b/RELEASES.md
@@ -1,3 +1,100 @@
+Version 1.98.0 (2026-08-20)
+==========================
+
+<a id="1.98.0-Language"></a>
+
+Language
+--------
+- [Allow shortening lifetime of `&mut` when unsize-coercing, even in an invariant position.](https://github.com/rust-lang/rust/pull/149219) For example, you can now coerce a `Cell<&'long mut i32>` to a `Cell<&'short mut dyn Send>`. Such shortenings were already previously allowed when coercing a `&mut` to a `&`, or coercing a `&` to a `&`.
+- [Add deny-by-default `invalid_runtime_symbol_definitions` lint and warn-by-default `suspicious_runtime_symbol_definitions` lint](https://github.com/rust-lang/rust/pull/155521)
+    - The lints currently specifically targets `core` runtime symbols like `memcmp`, `memset`, `strlen`, ... and is planned to be expanded in the next few releases.
+- [Add warn-by-default `c_void_returns` lint to check `core::ffi::c_void` as a return type](https://github.com/rust-lang/rust/pull/156379)
+
+
+<a id="1.98.0-Platform-Support"></a>
+
+Platform Support
+----------------
+- [Add `powerpc64-unknown-linux-gnuelfv2` as Tier 3](https://github.com/rust-lang/rust/pull/144220)
+- [Add `aarch64-unknown-linux-pauthtest` as Tier 3 target](https://github.com/rust-lang/rust/pull/155722)
+- [Promote `thumbv7a-none-eabi` to Tier 2](https://github.com/rust-lang/rust/pull/155763)
+- [Promote `thumbv7a-none-eabihf` to Tier 2](https://github.com/rust-lang/rust/pull/155763)
+- [Promote `thumbv7r-none-eabi` to Tier 2](https://github.com/rust-lang/rust/pull/155763)
+- [Promote `thumbv7r-none-eabihf` to Tier 2](https://github.com/rust-lang/rust/pull/155763)
+- [Promote `thumbv8r-none-eabihf` to Tier 2](https://github.com/rust-lang/rust/pull/155763)
+
+
+Refer to Rust's [platform support page][platform-support-doc]
+for more information on Rust's tiered platform support.
+
+[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
+
+<a id="1.98.0-Libraries"></a>
+
+Libraries
+---------
+- [Change `Location<'_>` lifetime to `'static` in `Panic[Hook]Info`](https://github.com/rust-lang/rust/pull/146561)
+- [Document panic in `RangeInclusive::from(legacy::RangeInclusive)`](https://github.com/rust-lang/rust/pull/155421)
+- [Document that `ManuallyDrop`'s `Box` interaction has been fixed](https://github.com/rust-lang/rust/pull/155750)
+- [Stabilize LoongArch CRC Intrinsics](https://github.com/rust-lang/rust/issues/156908)
+- [The `derive` macro is available at `{core,std}::derive`.](https://github.com/rust-lang/rust/issues/154645) This was previously [unintentionally stabilized in 1.96](https://github.com/rust-lang/rust/issues/159856), but is now [explicitly accepted](https://github.com/rust-lang/rust/issues/154645) as a stabilized API.
+  - Please note that the MSRV for `{core,std}::derive` will be 1.96, and not 1.98.
+
+
+<a id="1.98.0-Stabilized-APIs"></a>
+
+Stabilized APIs
+---------------
+
+- [`str::substr_range`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.substr_range)
+- [`[T]::subslice_range`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.subslice_range)
+- [`core::fmt::NumBuffer`](https://doc.rust-lang.org/stable/core/fmt/struct.NumBuffer.html)
+- [`<{integer}>::format_into`](https://doc.rust-lang.org/stable/core/primitive.usize.html#method.format_into)
+- [`Send/Sync for std::process::CommandArgs`](https://doc.rust-lang.org/stable/std/process/struct.CommandArgs.html#impl-Send-for-CommandArgs%3C'a%3E)
+- [`{fN}::algebraic_add`](https://doc.rust-lang.org/stable/core/primitive.f32.html#method.algebraic_add)
+- [`{fN}::algebraic_sub`](https://doc.rust-lang.org/stable/core/primitive.f32.html#method.algebraic_sub)
+- [`{fN}::algebraic_mul`](https://doc.rust-lang.org/stable/core/primitive.f32.html#method.algebraic_mul)
+- [`{fN}::algebraic_div`](https://doc.rust-lang.org/stable/core/primitive.f32.html#method.algebraic_div)
+- [`{fN}::algebraic_rem`](https://doc.rust-lang.org/stable/core/primitive.f32.html#method.algebraic_rem)
+- [`NonZero<{integer}>::from_str_radix`](https://doc.rust-lang.org/stable/core/num/struct.NonZero.html#method.from_str_radix-4)
+- [`String::from_utf16le`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.from_utf16le)
+- [`String::from_utf16le_lossy`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.from_utf16le_lossy)
+- [`String::from_utf16be`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.from_utf16be)
+- [`String::from_utf16be_lossy`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.from_utf16be_lossy)
+- [`[T]::strip_circumfix`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.strip_circumfix)
+- [`str::strip_circumfix`](https://doc.rust-lang.org/stable/core/primitive.str.html#method.strip_circumfix)
+- [`Atomic<T>::from_mut`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.Atomic.html#method.from_mut)
+- [`Atomic<T>::get_mut_slice`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.Atomic.html#method.get_mut_slice)
+- [`Atomic<T>::from_mut_slice`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.Atomic.html#method.from_mut_slice)
+- [`std::range::legacy`](https://doc.rust-lang.org/stable/std/range/legacy/index.html)
+
+
+<a id="1.98.0-Compatibility-Notes"></a>
+
+Compatibility Notes
+-------------------
+- [If fully elided, lifetime bounds of trait object types may now resolve differently or even get rejected in very specific niche scenarios](https://github.com/rust-lang/rust/pull/129543)
+- [Error in more cases of ambiguous imports](https://github.com/rust-lang/rust/pull/145108)
+- [Switch the destructors implementation for thread locals on Windows to use Fiber Local Storage (FLS)](https://github.com/rust-lang/rust/pull/148799)
+- [Convert some cases of the `ambiguous_glob_imports` lint into a hard error](https://github.com/rust-lang/rust/pull/149195)
+- [Where-bounds of the form `Type = Type` and `Type == Type` are no longer syntactically allowed](https://github.com/rust-lang/rust/pull/153513)
+- [Ensure Send/Sync is not implemented for std::env::Vars{,Os}](https://github.com/rust-lang/rust/pull/155153)
+- [Fix that in some attributes, arguments were not properly rejected](https://github.com/rust-lang/rust/pull/155193)
+- [`repr(transparent)` is now more strict about which fields have "trivial" layout and hence can be ignored: `repr(C)` types, types with private fields, and `#[non_exhaustive]` types are no longer considered "trivial"](https://github.com/rust-lang/rust/pull/155299)
+- [Correctly check whether types have equal size in `transmute()` when some `repr` attributes are involved.](https://github.com/rust-lang/rust/pull/155418)
+- [More characters are escaped when printing strings and chars](https://github.com/rust-lang/rust/pull/155527)
+- [Implement fast path for `derive(PartialOrd)` when deriving `Ord`](https://github.com/rust-lang/rust/pull/155598)
+  This can break crates in practice where a type's PartialOrd and Ord impls were inconsistent with each other.
+- [Add temporary scope to `assert_eq` and `assert_ne`](https://github.com/rust-lang/rust/pull/155739)
+- Closed a hole in the pattern matching [structural equality](https://doc.rust-lang.org/reference/patterns.html#constant-patterns) check, preventing cases where a match of a constant would be allowed, despite disagreeing with a manually written `PartialEq` implementation, when a `derive(PartialEq)` implementation for that type also exists.
+- [On Emscripten the WASM exception handling ABI is now unconditionally used](https://github.com/rust-lang/rust/pull/156928) The `-Zemscripten-wasm-eh=false` flag to switch back to JS exceptions has been removed.
+- [The UNSAFE_CODE lint is now consistently emitted for all unsafe attributes](https://github.com/rust-lang/rust/pull/157201)
+- [Solaris: remove `File::lock` implementation, it has the wrong semantics (return "unsupported" instead)](https://github.com/rust-lang/rust/pull/157509)
+- [Windows-gnu targets now specify baseline tools versions](https://github.com/rust-lang/rust/pull/158020)
+- [rustfmt now discovers module files that are defined in `cfg_select!`](https://github.com/rust-lang/rust/pull/158372)
+  This may cause more code to be formatted which was previously ignored.
+
+
 Version 1.97.1 (2026-07-16)
 ==========================
 

diff --git a/REUSE.toml b/REUSE.toml
@@ -208,3 +208,12 @@ SPDX-FileCopyrightText = [
     "Copyright (C) 2000-2024 Free Software Foundation, Inc.",
 ]
 SPDX-License-Identifier = "GCC-exception-3.1"
+
+ [[annotations]]
+ path = "compiler/rustc_middle/src/ptrauth/llvm_siphash/tests.rs"
+ precedence = "override"
+ SPDX-FileCopyrightText = [
+     "2003-2019 University of Illinois at Urbana-Champaign.",
+     "The Rust Project Developers (see https://thanks.rust-lang.org)",
+ ]
+ SPDX-License-Identifier = "Apache-2.0 WITH LLVM-exception AND (Apache-2.0 OR MIT)"
diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
@@ -1041,7 +1041,6 @@ impl Step for Size {
     }
 
     #[inline]
-    #[cfg(not(bootstrap))]
     fn forward_overflowing(start: Self, count: usize) -> (Self, bool) {
         let (s, o) = u64::forward_overflowing(start.bytes(), count);
         (Self::from_bytes(s), o)
@@ -1063,7 +1062,6 @@ impl Step for Size {
     }
 
     #[inline]
-    #[cfg(not(bootstrap))]
     fn backward_overflowing(start: Self, count: usize) -> (Self, bool) {
         let (s, o) = u64::backward_overflowing(start.bytes(), count);
         (Self::from_bytes(s), o)
@@ -2171,8 +2169,8 @@ pub struct LayoutData<FieldIdx: Idx, VariantIdx: Idx> {
     pub max_repr_align: Option<Align>,
 
     /// The alignment the type would have, ignoring any `repr(align)` but including `repr(packed)`.
-    /// Only used on aarch64-linux, where the argument passing ABI ignores the requested alignment
-    /// in some cases.
+    /// Only used on aarch64-linux and arm, where the argument passing ABI ignores the requested
+    /// alignment in some cases.
     pub unadjusted_abi_align: Align,
 
     /// The randomization seed based on this type's own repr and its fields.

diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -691,7 +691,7 @@ impl<'diag, 'tcx> MirBorrowckCtxt<'_, 'diag, 'tcx> {
         if !clauses.instantiate_identity(tcx).clauses.iter().any(|clause| {
             clause.as_trait_clause().is_some_and(|tc| {
                 tc.self_ty().skip_binder().is_param(param.index)
-                    && tc.polarity() == ty::PredicatePolarity::Positive
+                    && tc.polarity() == ty::ClausePolarity::Positive
                     && supertrait_def_ids(tcx, tc.def_id())
                         .flat_map(|trait_did| tcx.associated_items(trait_did).in_definition_order())
                         .any(|item| item.is_method())

diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -1228,7 +1228,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
                 tcx.clauses_of(callee_def_id).instantiate(tcx, generic_args).clauses.iter().any(
                     |clause| {
                         clause.as_trait_clause().is_some_and(|trait_pred| {
-                            trait_pred.polarity() == ty::PredicatePolarity::Positive
+                            trait_pred.polarity() == ty::ClausePolarity::Positive
                                 && tcx.fn_trait_kind_from_def_id(trait_pred.def_id())
                                     == Some(ty::ClosureKind::Fn)
                                 && trait_pred.self_ty().skip_binder().peel_refs()

diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs
@@ -131,9 +131,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         category: ConstraintCategory<'tcx>,
     ) {
         self.prove_clause(
-            ty::ClauseKind::Trait(ty::TraitPredicate {
+            ty::ClauseKind::Trait(ty::TraitClause {
                 trait_ref,
-                polarity: ty::PredicatePolarity::Positive,
+                polarity: ty::ClausePolarity::Positive,
             }),
             locations,
             category,

diff --git a/compiler/rustc_codegen_cranelift/rust-toolchain.toml b/compiler/rustc_codegen_cranelift/rust-toolchain.toml
@@ -1,4 +1,4 @@
 [toolchain]
-channel = "nightly-2026-08-17"
+channel = "nightly-2026-08-19"
 components = ["rust-src", "rustc-dev", "llvm-tools", "rustfmt"]
 profile = "minimal"
diff --git a/compiler/rustc_codegen_gcc/src/context.rs b/compiler/rustc_codegen_gcc/src/context.rs
@@ -495,7 +495,9 @@ impl<'gcc, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         let entry_name = self.sess().target.entry_name.as_ref();
         if !self.functions.borrow().contains_key(entry_name) {
             let conv = cfg_select! {
-                feature = "master" => conv_to_fn_attribute(self.sess(), self.sess().target.entry_abi),
+                feature = "master" => {
+                    conv_to_fn_attribute(self.sess(), self.sess().target.entry_abi)
+                }
                 _ => None,
             };
             Some(self.declare_entry_fn(entry_name, fn_type, conv))

diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -7,7 +7,6 @@
 #![feature(try_blocks)]
 #![recursion_limit = "256"]
 // tidy-alphabetical-end
-#![cfg_attr(bootstrap, feature(string_from_utf8_lossy_owned))]
 
 //! This crate contains codegen code that is used by all codegen backends (LLVM and others).
 //! The backend-agnostic functions of this crate use functions defined in various traits that

diff --git a/compiler/rustc_data_structures/src/obligation_forest/graphviz.rs b/compiler/rustc_data_structures/src/obligation_forest/graphviz.rs
@@ -18,8 +18,8 @@ impl<O: ForestObligation> ObligationForest<O> {
     /// A few post-processing that you might want to do make the forest easier to visualize:
     ///
     ///  * `sed 's,std::[a-z]*::,,g'` — Deletes the `std::<package>::` prefix of paths.
-    ///  * `sed 's,"Binder(TraitPredicate(<\(.*\)>)) (\([^)]*\))","\1 (\2)",'` — Transforms
-    ///    `Binder(TraitPredicate(<predicate>))` into just `<predicate>`.
+    ///  * `sed 's,"Binder(TraitClause(<\(.*\)>)) (\([^)]*\))","\1 (\2)",'` — Transforms
+    ///    `Binder(TraitClause(<predicate>))` into just `<predicate>`.
     #[allow(dead_code)]
     pub fn dump_graphviz<P: AsRef<Path>>(&self, dir: P, description: &str) {
         static COUNTER: AtomicUsize = AtomicUsize::new(0);

diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
@@ -97,10 +97,10 @@ declare_features! (
     /// Allows `extern "C-unwind" fn` to enable unwinding across ABI boundaries and treat `extern "C" fn` as nounwind.
     (accepted, c_unwind, "1.81.0", Some(74990)),
     /// Allows using C-variadics.
-    (accepted, c_variadic, "CURRENT_RUSTC_VERSION", Some(44930)),
+    (accepted, c_variadic, "1.99.0", Some(44930)),
     /// Allows defining c-variadic naked functions with any extern ABI that is allowed
     /// on c-variadic foreign functions.
-    (accepted, c_variadic_naked_functions, "CURRENT_RUSTC_VERSION", Some(148767)),
+    (accepted, c_variadic_naked_functions, "1.99.0", Some(148767)),
     /// Allows `#[cfg_attr(predicate, multiple, attributes, here)]`.
     (accepted, cfg_attr_multi, "1.33.0", Some(54881)),
     /// Allows the use of `#[cfg(<true/false>)]`.

diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
@@ -255,7 +255,7 @@ declare_features! (
     /// Allows checking whether or not the backend correctly supports unstable float types.
     (internal, cfg_target_has_reliable_f16_f128, "1.88.0", None),
     /// Allows checking whether or not the target might have thread support.
-    (internal, cfg_target_has_threads, "CURRENT_RUSTC_VERSION", None),
+    (internal, cfg_target_has_threads, "1.99.0", None),
     /// Allows identifying the `compiler_builtins` crate.
     (internal, compiler_builtins, "1.13.0", None),
     /// Allows skipping `ConstParamTy_` trait implementation checks
@@ -397,7 +397,7 @@ declare_features! (
     /// Target features on arm.
     (unstable, arm_target_feature, "1.27.0", Some(150246)),
     /// Allows using `const` operands with pointer in inline assembly.
-    (unstable, asm_const_ptr, "CURRENT_RUSTC_VERSION", Some(128464)),
+    (unstable, asm_const_ptr, "1.99.0", Some(128464)),
     /// Enables experimental inline assembly support for additional architectures.
     (unstable, asm_experimental_arch, "1.58.0", Some(93335)),
     /// Enables experimental register support in inline assembly.
@@ -452,7 +452,7 @@ declare_features! (
     /// Allows to use the `#[cfi_encoding = ""]` attribute.
     (unstable, cfi_encoding, "1.71.0", Some(89653)),
     /// Allow to have type alias types for inter-crate use.
-    (incomplete, checked_type_aliases, "CURRENT_RUSTC_VERSION", Some(112792)),
+    (incomplete, checked_type_aliases, "1.99.0", Some(112792)),
     /// The `clflushopt` target feature on x86.
     (unstable, clflushopt_target_feature, "1.98.0", Some(157096)),
     /// Allows `for<...>` on closures and coroutines.
@@ -518,7 +518,7 @@ declare_features! (
     /// Allows macros to customize macro argument matcher diagnostics.
     (unstable, diagnostic_on_unmatched_args, "1.97.0", Some(155642)),
     // Used by macros to not show their bodies in error messages. No-op with `-Z macro-backtrace`.
-    (unstable, diagnostic_opaque, "CURRENT_RUSTC_VERSION", Some(158813)),
+    (unstable, diagnostic_opaque, "1.99.0", Some(158813)),
     /// Allows `#[doc(cfg(...))]`.
     (unstable, doc_cfg, "1.21.0", Some(43781)),
     /// Allows `#[doc(masked)]`.
@@ -630,7 +630,7 @@ declare_features! (
     /// Provides a way to concatenate identifiers using metavariable expressions.
     (unstable, macro_metavar_expr_concat, "1.81.0", Some(124225)),
     /// Allows directly represented generic_const_args without the `direct_const_arg!` macro.
-    (incomplete, macroless_generic_const_args, "CURRENT_RUSTC_VERSION", Some(159006)),
+    (incomplete, macroless_generic_const_args, "1.99.0", Some(159006)),
     /// Allows `#[marker]` on certain traits allowing overlapping implementations.
     (unstable, marker_trait_attr, "1.30.0", Some(29864)),
     /// Enable mgca `type const` syntax before expansion.
@@ -660,13 +660,13 @@ declare_features! (
     /// Allows `mut ref` and `mut ref mut` identifier patterns.
     (incomplete, mut_ref, "1.79.0", Some(123076)),
     /// Allows `mut(crate) field: Type` restrictions.
-    (unstable, mut_restriction, "CURRENT_RUSTC_VERSION", Some(105077)),
+    (unstable, mut_restriction, "1.99.0", Some(105077)),
     /// Allows using `#[naked]` on `extern "Rust"` functions.
     (unstable, naked_functions_rustic_abi, "1.88.0", Some(138997)),
     /// Allows using `#[target_feature(enable = "...")]` on `#[naked]` on functions.
     (unstable, naked_functions_target_feature, "1.86.0", Some(138568)),
     /// Allows providing names to parameters of `impl Fn` etc
-    (incomplete, named_fn_trait_parameters, "CURRENT_RUSTC_VERSION", Some(158499)),
+    (incomplete, named_fn_trait_parameters, "1.99.0", Some(158499)),
     /// Allows specifying the as-needed link modifier
     (unstable, native_link_modifiers_as_needed, "1.53.0", Some(81490)),
     /// Allow negative trait implementations.

diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -2726,7 +2726,7 @@ fn param_env_with_gat_bounds<'tcx>(
             }
             _ => clauses.push(
                 ty::Binder::bind_with_vars(
-                    ty::ProjectionPredicate {
+                    ty::ProjectionClause {
                         projection_term: ty::AliasTerm::new_from_def_id(
                             tcx,
                             trait_ty.def_id,

diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -1323,7 +1323,7 @@ fn check_impl<'tcx>(
                     trait_ref,
                 );
                 let trait_pred =
-                    ty::TraitPredicate { trait_ref, polarity: ty::PredicatePolarity::Positive };
+                    ty::TraitClause { trait_ref, polarity: ty::ClausePolarity::Positive };
                 let mut obligations = traits::wf::trait_obligations(
                     wfcx.infcx,
                     wfcx.param_env,

diff --git a/compiler/rustc_hir_analysis/src/coherence/builtin.rs b/compiler/rustc_hir_analysis/src/coherence/builtin.rs
@@ -924,9 +924,9 @@ fn infringing_fields_error<'tcx>(
                             .or_default()
                             .push(error.obligation.cause.span);
                     }
-                    if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(ty::TraitPredicate {
+                    if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(ty::TraitClause {
                         trait_ref,
-                        polarity: ty::PredicatePolarity::Positive,
+                        polarity: ty::ClausePolarity::Positive,
                         ..
                     })) = error_predicate.kind().skip_binder()
                     {