Codegen option: Prefer dynamic linking to static linking.
Unstable Cargo option: Compile the standard library yourself.
Unstable rustdoc option: Normalize/evaluate types when generating docs
Unstable option: Polymorphization.
Unstable option: Randomize the layout of types.
Unstable option: THIR unsafeck
Unstable option: unpretty debug print
Unstable option: MIR validation
Area: Concerning the application binary interface (ABI).
Area: Custom and system allocators
Area: Associated items such as associated types and consts.
Area: atomics, barriers, and sync primitives
Area: auto traits (`auto trait Send`)
Issue related to autovectorization, which can impact perf or code size.
Area: Our Github Actions CI
Area: Command line interface to the compiler.
Area: closures (`|args| { .. }`)
Area: Source-based code coverage (-Cinstrument-coverage)
Area: implicit and explicit `expr as Type` coercions
Area: Concerning coinduction, most often for auto traits
Area: Concurrency related issues.
Area: constant evaluation (mir interpretation)