{
  "$type": "site.standard.document",
  "bskyPostRef": {
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    "uri": "at://did:plc:ivbknywyskln22er3nkssdhl/app.bsky.feed.post/3mfogho5u3dc2"
  },
  "path": "/t/pre-rfc-function-parameter-defaults/24011#post_4",
  "publishedAt": "2026-02-25T07:41:47.000Z",
  "site": "https://internals.rust-lang.org",
  "textContent": "What I was thinking of was patterns like axum and bevy use to accept functions of various arities in higher-order methods. (e.g. `routing::get` for axum).\n\nAdding a default to a parameter of a function that's passed to such a higher-order function w/o specifying type params would break compilation due to those type params no longer having one unambiguous substitution at that callsite.\n\nI can post a concrete example later.",
  "title": "Pre-RFC: Function parameter defaults"
}