{
  "$type": "site.standard.document",
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  "path": "/t/f-pattern-types-subsets-enums-using-as/24048#post_9",
  "publishedAt": "2026-03-03T04:35:35.000Z",
  "site": "https://internals.rust-lang.org",
  "textContent": "To clarify, they can be used unstably, but they are very minimal. You'd need to use a macro to create them (or transmute). I tried previously, but they were just too unstable for me to really make use of.\n\nI am saying we are a long way from them being stable, since currently, there are no plans for them to ever be stable that I am aware of.\n\nI think the features you'd need are:\n\n\n    #![feature(pattern_types, rustc_attrs)]\n    #![feature(core_pattern_type)]\n    #![feature(core_pattern_types)]\n    #![allow(incomplete_features)]\n\n\n...but it has been a while, so I might be mistaken.",
  "title": "F-pattern_types : Subsets enums using as"
}