Issues

• Tracking issue for release notes of #139984: Tracking Issue for CStr::display

  F-cstr_displayrelnotesrelnotes-tracking-issueT-libs
  rust-lang/rust#163710 · Filter by author rustbot opened on Oct 3, 2026

• Tracking issue for release notes of #162761: Lower attributes for functions without bodies

  needs-triagerelnotesrelnotes-needs-reviewrelnotes-tracking-issueT-compilerT-lang
  rust-lang/rust#163709 · Filter by author rustbot opened on Oct 3, 2026

• Tracking issue for release notes of #163220: Performance regression in Criterion benchmark of AVX2 code on x86_64-pc-windows-msvc

  A-SIMDneeds-triageO-windows-msvcrelnotesrelnotes-needs-reviewrelnotes-tracking-issueT-compilerT-opsem
  rust-lang/rust#163708 · Filter by author rustbot opened on Oct 3, 2026

• x86-64 code looks too complex and not optimal for equality functions when simple bitwise comparison available.

  needs-triage
  rust-lang/rust#163707 · Filter by author spquix opened on Oct 3, 2026

• Tracking issue for release notes of #162974: FCW for #[panic_handler] on unsafe fn.

  needs-triagerelnotesrelnotes-tracking-issueT-compilerT-lang
  rust-lang/rust#163706 · Filter by author rustbot opened on Oct 3, 2026

• Tracking issue for release notes of #163161: implement FCW for rustc_allowed_through_unstable_modules items

  needs-triagerelnotesrelnotes-needs-reviewrelnotes-tracking-issueT-clippyT-compilerT-lang
  rust-lang/rust#163705 · Filter by author rustbot opened on Oct 3, 2026

• Tracking issue for release notes of #162652: Syntactically reject leading parenthesized precise capturing lists in bare trait object types ((use<…>)+)

  relnotesrelnotes-tracking-issueT-compilerT-lang
  rust-lang/rust#163704 · Filter by author rustbot opened on Oct 3, 2026

• Tracking issue for release notes of #162131: 1.99 beta crater regression: expected item after attributes

  A-doctestsA-parserneeds-triagerelnotesrelnotes-needs-reviewrelnotes-tracking-issueT-langT-rustdoc
  rust-lang/rust#163702 · Filter by author rustbot opened on Oct 3, 2026

• Compiling error for all *-nuttx-* targets

  -Zbuild-stdT-libs
  rust-lang/rust#163700 · Filter by author Wyvern opened on Oct 3, 2026
  1

• Tracking issue for MCP 1038: Create new Tier 3 Target for QTEE: aarch64-unknown-qtee

  B-MCP-approvedC-tracking-issueS-tracking-unimplementedT-compiler
  rust-lang/rust#163698 · Filter by author rustbot opened on Oct 3, 2026

• Tracking Issue for MCP 1016: -Zasync-panic

  C-tracking-issueI-lang-nominated
  rust-lang/rust#163678 · Filter by author diondokter opened on Oct 2, 2026

• Rust 1.99 regression: fat LTO leaves short constant string comparisons as bcmp calls

  A-LLVMC-optimizationI-prioritizeregression-untriagedT-compiler
  rust-lang/rust#163677 · Filter by author armano2 opened on Oct 2, 2026
  1

• dec2flt::decimal_seq overflows an i32 subtraction on a large valid decimal when overflow checks are enabled

  A-floating-pointC-bugT-libs
  rust-lang/rust#163676 · Filter by author wpegden opened on Oct 2, 2026
  11

  

• std::io::Read incorrectly has no marked required methods

  A-docsT-rustdoc
  rust-lang/rust#163675 · Filter by author AlaskanEmily opened on Oct 2, 2026
  1

• str::parse::<f64>() returns 1.0 for an overflowing decimal with a long fractional part

  A-floating-pointA-strC-bugT-libs
  rust-lang/rust#163674 · Filter by author wpegden opened on Oct 2, 2026
  6

  

• Tracking issue for release notes of #161998: Support type-relative assoc item paths in generic param defaults & const param types

  relnotesrelnotes-tracking-issueT-types
  rust-lang/rust#163662 · Filter by author rustbot opened on Oct 2, 2026
  2

• Unexpected lifetime error when async function return a borrowed value from function's argument

  A-borrow-checkerC-bugfixed-by-poloniusT-types
  rust-lang/rust#163659 · Filter by author ultimaweapon opened on Oct 2, 2026
  3

• Linker plugin LTO broken?

  A-LTOC-bugneeds-triage
  rust-lang/rust#163652 · Filter by author bjorn3 opened on Oct 2, 2026

• New trait solver regresses compile time error messages significantly

  A-diagnosticsD-terseD-verboseregression-from-stable-to-nightlyT-compilerT-typesWG-trait-system-refactor
  rust-lang/rust#163643 · Filter by author weiznich opened on Oct 2, 2026
  1

• Improved diagnostic for tuple impl's doesn't always work

  A-diagnosticsT-compiler
  rust-lang/rust#163641 · Filter by author weiznich opened on Oct 2, 2026
  5

  

• aarch64-apple-darwin: -Cprofile-generate binary segfaults at exit in initializeValueProfRuntimeRecord since LLVM 23

  A-PGOneeds-triageO-macosP-highregression-from-stable-to-stable
  rust-lang/rust#163640 · Filter by author BartWaardenburg opened on Oct 2, 2026
  1

• Tracking issue for release notes of #161805: Prefer ambiguous candidates when deduplicating traits in scope, so ambiguous_glob_imported_traits doesn't depend on import order

  needs-triagerelnotesrelnotes-needs-reviewrelnotes-tracking-issueT-compiler
  rust-lang/rust#163631 · Filter by author rustbot opened on Oct 2, 2026 · 1.100.0

• 1.99.0 regression: compilation never finishes on aarch64 at opt-level=3 (loop-vectorize, cos/sin loop with a wrap)

  A-LLVMI-hangneeds-triageO-AArch64P-highregression-from-stable-to-stable
  rust-lang/rust#163626 · Filter by author jl1nie opened on Oct 1, 2026
  4

  

• Tracking issue for release notes of #163572: Update the minimum external LLVM to 22

  A-CIA-LLVMA-testsuiteF-explicit_tail_callsrelnotesrelnotes-tracking-issueT-bootstrapT-compilerT-infra
  rust-lang/rust#163620 · Filter by author rustbot opened on Oct 1, 2026 · 1.101.0

• Failure to run PGO instrumentation on Rust 1.99.0

  A-LLVMA-PGOC-bugI-prioritizeregression-from-stable-to-stableS-has-bisectionT-compiler
  rust-lang/rust#163616 · Filter by author davidhewitt opened on Oct 1, 2026
  5