{
  "$type": "site.standard.document",
  "bskyPostRef": {
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    "uri": "at://did:plc:ivbknywyskln22er3nkssdhl/app.bsky.feed.post/3meetnsdpu3r2"
  },
  "path": "/t/what-s-where-size-kind-extra/23987#post_2",
  "publishedAt": "2026-02-08T21:02:46.000Z",
  "site": "https://internals.rust-lang.org",
  "textContent": "This bound is essentially used to declare that your const computation (`SIZE + Kind::EXTRA`) can be evaluated. In this particular case, it means that the addition should not overflow `usize`. It also can be used to declare that types created with the const computation result have a proper size (i.e. less than `isize::MAX` bytes) by using `u8` instead of `()` in the bound.\n\nIn other words, the bound prevents potential monomorphization errors (which are, unfortunately, already exist in Rust for some corner cases...).\n\ndaniel-pfeiffer:\n\n> is this temporary, until some prerequisite gets implemented?\n\nIIRC, yes. Though I can not link exact proposals out of my head.",
  "title": "What’s where [(); SIZE + Kind::EXTRA]:?"
}