… return types

… r=RalfJung,oli-obk

Const floating point bitcasts and classification

Makes the `f32` and `f64` methods described in rust-lang#72447 and rust-lang#72505 unstably const.

r? @RalfJung

…atthewjasper

On recursive ADT, provide indirection structured suggestion

…sper

linker: MSVC supports linking static libraries as a whole archive

…, r=nikomatsakis

Further tweak lifetime errors involving `dyn Trait` and `impl Trait` in return position

* Suggest substituting `'static` lifetime in impl/dyn `Trait + 'static` instead of `Trait + 'static + '_`
* When `'static` is explicit, also suggest constraining argument with it
* Reduce verbosity of suggestion message and mention lifetime in label
* Tweak output for overlapping required/captured spans
* Give these errors an error code

Follow up to rust-lang#72543.

r? @nikomatsakis

…, r=dtolnay

Migrate to numeric associated consts

The deprecation PR is rust-lang#72885

cc rust-lang#68490
cc rust-lang/rfcs#2700