They're unused now.

This is consistent with types.

`saturating_add` example was not parameterized, but passed because the `u8` would saturate successfully

Co-authored-by: lzutao <[email protected]>

…=nikomatsakis

Clean up type alias impl trait implementation

- Removes special case for top-level impl trait
- Removes associated opaque types
- Forbid lifetime elision in let position impl trait. This is consistent with the behavior for inferred types.
- Handle lifetimes in type alias impl trait more uniformly with other parameters

cc rust-lang#69323
cc rust-lang#63063
Closes rust-lang#57188
Closes rust-lang#62988
Closes rust-lang#69136

Fix `is_const_context`, update `check_for_cast`

A better version of rust-lang#71477

Adds `fn enclosing_body_owner` and uses it in `is_const_context`.
`is_const_context` now uses the same mechanism as `mir_const_qualif` as it was previously incorrect.
Renames `is_const_context` to `is_inside_const_context`.

I also updated `check_for_cast` in the second commit, so r? @estebank

(I removed one lvl of indentation, so it might be easier to review by hiding whitespace changes)

…atthewjasper

On recursive ADT, provide indirection structured suggestion

…, r=dtolnay

Migrate to numeric associated consts

The deprecation PR is rust-lang#72885

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

…an-DPC

Clean up E0642 explanation

r? @Dylan-DPC

…enkov

Add new E0762 error code

Automatically prioritize unsoundness issues

r? @spastorino cc @Mark-Simulacrum @rust-lang/wg-prioritization

Fix doctest template

`saturating_add` example was not parameterized, but passed because the `u8` would saturate successfully

x.py: with --json-output, forward cargo's JSON

Fixes rust-lang#73209

r? @Mark-Simulacrum