The error mentions `///`, when it's actually `//!`:

error[E0658]: attributes on expressions are experimental
 --> test.rs:4:9
  |
4 |         //! wah
  |         ^^^^^^^
  |
  = note: see issue rust-lang#15701 <rust-lang#15701> for more information
  = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
  = help: `///` is for documentation comments. For a plain comment, use `//`.

This change sets the appropriate channel by default when using nightly,
beta or stable source tarballs.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

…iler-errors

expand: fix minor diagnostics bug

The error mentions `///`, when it's actually `//!`:

```
error[E0658]: attributes on expressions are experimental
 --> test.rs:4:9
  |
4 |         //! wah
  |         ^^^^^^^
  |
  = note: see issue rust-lang#15701 <rust-lang#15701> for more information
  = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
  = help: `///` is for documentation comments. For a plain comment, use `//`.
```

Rename `flatten(_mut)` → `as_flattened(_mut)`

As requested by libs-api in rust-lang#95629 (comment)

(This is just the rename, not the stabilization, so can land without waiting on the FCP in that other issue.)

…ly, r=clubby789

set `rust.channel` properly in source tarballs

This change sets the appropriate channel by default when using nightly, beta or stable source tarballs.

Fixes rust-lang#124618

Remove duplicate word from addr docs

This PR simply removes a duplicate word from the addr docs for *mut T.

Report better WF obligation leaf obligations in new solver

r? lcnr