Rust 1.98.0

Rust 1.98.0 — released August 20, 2026. This release introduces lifetime-shortening improvements for &mut coercions, stabilizes core::fmt::NumBuffer and a broad set of integer and floating-point helper APIs, adds several new platform targets, and ships a list of compatibility notes that developers should review before upgrading.

Language

The headline language change allows shortening the lifetime of &mut when unsize-coercing, even in an invariant position. You can now coerce a Cell<&'long mut i32> to a Cell<&'short mut dyn Send> — something previously only permitted when coercing to a plain reference. In addition, the RISC-V d, e, and f target features are now stable for use in cfg(target_feature = "...").

Platform Support

• powerpc64-unknown-linux-gnuelfv2 added as a Tier 3 target
• aarch64-unknown-linux-pauthtest added as a Tier 3 target
• thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7r-none-eabi, thumbv7r-none-eabihf, and thumbv8r-none-eabihf promoted to Tier 2

Libraries

Location<'_> now uses a 'static lifetime in Panic[Hook]Info, and core::range::{legacy, RangeFull, RangeTo} have been stabilized along with documentation clarifications for RangeInclusive and ManuallyDrop.

Stabilized APIs

• core::fmt::NumBuffer and integer format_into
• Send/Sync for std::process::CommandArgs
• Floating-point algebraic_add, algebraic_sub, algebraic_mul, algebraic_div, and algebraic_rem
• NonZero<{integer}>::from_str_radix
• String::from_utf16le, from_utf16le_lossy, from_utf16be, and from_utf16be_lossy
• [T]::strip_circumfix and str::strip_circumfix
• Atomic<T>::from_mut, get_mut_slice, and from_mut_slice

Compatibility Notes

Several lints harden in this release. Some cases of the ambiguous_glob_imports lint become hard errors, a new deny-by-default invalid_runtime_symbol_definitions lint targets core runtime symbols, and repr(transparent) is stricter about which fields count as "trivial". Thread-local destructors on Windows now use FLS, and where-bounds of the form Type = Type are no longer syntactically allowed. Upgrade carefully and consult the official migration notes for the complete list.