This is a tracking issue for the RFC "target_feature 1.1" (rust-lang/rfcs#2396).

Issues: F-target_feature_11 target feature 1.1 RFC

People

Last updated in Mar 2023:

• Shepherd: gnzlbg @workingjubilee (person who can help answer tricky questions that arise during implementation)
• Lang team liaison: @joshtriplett (main point of contact from lang team)

Step

• Implement the RFC: Implement RFC 2396: #[target_feature] 1.1 #69274
• Adjust documentation: Document the target_feature_11 feature reference#1181
• Stabilization PR (see instructions on rustc-guide)
• Revert? Revert stabilization of #![feature(target_feature_11)] #108654
• I suppose we're off the end of the script, here. Bugs to fix:
  • #[target_feature] is allowed on main #108645
  • #[target_feature] is allowed on default implementations #108646
  • target_feature_11 rejects code that was previously accepted #108655
  • The extern "C" ABI of SIMD vector types depends on target features (tracking issue for abi_unsupported_vector_types future-incompatibility lint) #116558
  • The (stable) neon aarch64 target feature is unsound: it changes the float ABI #131058
• Re-stabilization PR: Stabilize target_feature_11 #134090

Unresolved questions

• target_feature_11 allows bypassing safety checks through Fn* traits #72012 -- soundness hole where safe target-feature functions implement the Fn traits.
• target-feature 1.1: should closures inherit target-feature annotations? #73631 -- behavior of closures and target-features