{
"$type": "site.standard.document",
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"uri": "at://did:plc:ivbknywyskln22er3nkssdhl/app.bsky.feed.post/3mlge3oqt6y32"
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"path": "/t/type-inference-failure-when-accessing-a-value-before-its-type-is-resolved/24232#post_8",
"publishedAt": "2026-05-09T11:38:47.000Z",
"site": "https://internals.rust-lang.org",
"tags": [
"@jplatte",
"@tczajka"
],
"textContent": "@jplatte It’s essentially the same phenomenon, but triggered in a different way.\n\n@tczajka Your example is indeed much clearer.\n\n* * *\n\n**Working case:**\n\n`A` has an unknown type → `A = B` → `B` has a known type → **compiles successfully**\n\n**Failing case:**\n\n`A` has an unknown type → access `A.field` → `A = B` → `B` has a known type → **type inference fails**\n\nEven though the IDE (e.g. Rust Analyzer) resolves the type correctly, the compiler still reports a type inference error.\n\nIt seems that type inference loses track of the type if the value from **A** is accessed or manipulated before it is assigned to **B**.\n\nThis would be a welcome improvement.\n\n_I revised the post title and content (as well as the GitHub issue) so that the problem is no longer described as being specific to loops, but rather presented in a more general way._",
"title": "Type inference failure when accessing a value before its type is resolved"
}