From 2a0c72e3a9dc1c4a8009e748900bdc6816bc640a Mon Sep 17 00:00:00 2001 From: Zalathar Date: Mon, 12 May 2025 18:08:15 +1000 Subject: [PATCH] Remove obsolete reference to `unsized_tuple_coercion` --- src/doc/rustc-dev-guide/src/traits/unsize.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/src/doc/rustc-dev-guide/src/traits/unsize.md b/src/doc/rustc-dev-guide/src/traits/unsize.md index dd57a1b07967..98a445257481 100644 --- a/src/doc/rustc-dev-guide/src/traits/unsize.md +++ b/src/doc/rustc-dev-guide/src/traits/unsize.md @@ -32,21 +32,21 @@ Built-in implementations are provided for: ## Structural implementations -There are two implementations of `Unsize` which can be thought of as +There is one implementation of `Unsize` which can be thought of as structural: -* `(A1, A2, .., An): Unsize<(A1, A2, .., U)>` given `An: Unsize`, which - allows the tail field of a tuple to be unsized. This is gated behind the - [`unsized_tuple_coercion`] feature. * `Struct<.., Pi, .., Pj, ..>: Unsize>` given `TailField: Unsize`, which allows the tail field of a struct to be unsized if it is the only field that mentions generic parameters `Pi`, .., `Pj` (which don't need to be contiguous). -The rules for the latter implementation are slightly complicated, since they +The rules for struct unsizing are slightly complicated, since they may allow more than one parameter to be changed (not necessarily unsized) and are best stated in terms of the tail field of the struct. -[`unsized_tuple_coercion`]: https://doc.rust-lang.org/beta/unstable-book/language-features/unsized-tuple-coercion.html +(Tuple unsizing was previously implemented behind the feature gate +`unsized_tuple_coercion`, but the implementation was removed by [#137728].) + +[#137728]: https://github.com/rust-lang/rust/pull/137728 ## Upcasting implementations