Auto merge of #160789 - jhpratt:rollup-zFeRr02, r=jhpratt

Rollup of 5 pull requests

Successful merges:

 - rust-lang/rust#158517 (Initial implementation of named `Fn` trait parameters)
 - rust-lang/rust#158587 (check if len of array const arg matches the expected len of the type when lowering to valtree)
 - rust-lang/rust#160748 (Add regression test for cross-crate assoc const private field leak in rustdoc)
 - rust-lang/rust#160708 (remove old update mechanism)
 - rust-lang/rust#160768 (Fix autodiff_illegal.rs test)