Rollup merge of #137728 - Darksonn:no-tuple-unsize, r=oli-obk

Remove unsizing coercions for tuples

See rust-lang/rust#42877 (comment) and below comments for justification.

Tracking issue: #42877
Fixes: #135217

Author: jieyouxu

crates/ide-db/src/generated/lints.rs

@@ -12311,40 +12311,6 @@ fn main() {
 ```
 
 will unnecessarily extend the stack frame.
-"##,
-        default_severity: Severity::Allow,
-        warn_since: None,
-        deny_since: None,
-    },
-    Lint {
-        label: "unsized_tuple_coercion",
-        description: r##"# `unsized_tuple_coercion`
-
-The tracking issue for this feature is: [#42877]
-
-[#42877]: https://github.com/rust-lang/rust/issues/42877
-
-------------------------
-
-This is a part of [RFC0401]. According to the RFC, there should be an implementation like this:
-
-```rust,ignore (partial-example)
-impl<..., T, U: ?Sized> Unsized<(..., U)> for (..., T) where T: Unsized<U> {}
-```
-
-This implementation is currently gated behind `#[feature(unsized_tuple_coercion)]` to avoid insta-stability. Therefore you can use it like this:
-
-```rust
-#![feature(unsized_tuple_coercion)]
-
-fn main() {
-    let x : ([i32; 3], [i32; 3]) = ([1, 2, 3], [4, 5, 6]);
-    let y : &([i32; 3], [i32]) = &x;
-    assert_eq!(y.1[0], 4);
-}
-```
-
-[RFC0401]: https://github.com/rust-lang/rfcs/blob/master/text/0401-coercions.md
 "##,
         default_severity: Severity::Allow,
         warn_since: None,