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# System prepended metadata

title: Social hour - "what's your favorite unstable feature?"

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# Social hour - "what's your favorite unstable feature?"

- Wesley Wiser: if-let chains, want it often in my own code
- Esteban: Box patterns, interested in seeing a stabilized version of that
    - Common issue in the compiler, because we box large enum variants.
- Richard Boyd: option to set output directory for `cargo build`
    - Want this to put the binary in the right place to zip up for an AWS Lambda function
    - Josh: Should be feasible to stabilize
- Sean Chen: Const generics? Found the static-rc crate interesting.
- Josh: inline asm, ReadBuf (standard library Read without having to initialize the buffer)
    - ReadBuf because it's a blocker for standardized async IO traits
- Felix: "favorite" feature is the may_dangle attribute; really want to change it, but want a better solution to the underlying problem. Part of the dropck system. Vec has a generic parameter, when you drop the Vec it drops all the elements, those drops can call methods on the type, do those methods access something that's been dropped already?
- Niko: Specialization - want the ability to write "OO-like patterns", have a general case and then tighten it. For instance, a visitor, where I want to refine the implementation of the methods.
- Richard Boyd: Code coverage! -Z features
- Felix: All the -Z unpretty features
- Niko: -Z dump-mir
- Josh: -Z strip
- Felix: Code rewriting
    - Josh: +1
    - rerast, but it's deprecated and uses old nightly compiler internals
    - rust-analyzer, but that requires an editor with rust-analyzer support, and doesn't work as a standalone command-line tool
- Jane: Try trait v2