…tuples, r=jdonszelmann

  don't emit `unused_results` lint for tuples of "trivial" types

r? @jdonszelmann
Fixes rust-lang#153144.

So it turns out rust-lang#153018 had a sneaky behavior change in the way tuples are handled and the old behavior wasn't tested.

Consider these tuples:

```rust
((), ());
((), 1);
```

Neither of them is `must_use`, so they are potential candidates for `unused_results`. So the question is whatever said tuples are considered "trivial" and thus if they end up emitting `unused_results` or not.

Here is a comparison table between PRs:
<table>
<tr><td>stable</td><td>After rust-lang#153018</td><td>After this PR</td></tr><tr><td>

```rust
((), ()); // trivial
((), 1); // trivial
```
</td>
<td>

```rust
((), ()); //~ warn: unused_results
((), 1); //~ warn: unused_results
```
</td>
<td>

```rust
((), ()); // trivial
((), 1); //~ warn: unused_results
```
</td>
</tr>
  <tr>
    <td>

tuples are trivial if **any** of their fields are trivial
    </td>
    <td>

tuples are never trivial
    </td>
    <td>

tuples are trivial if **all** of their fields are trivial
    </td>
  </tr>
</table>

…tuples, r=jdonszelmann

  don't emit `unused_results` lint for tuples of "trivial" types

r? @jdonszelmann
Fixes rust-lang#153144.

So it turns out rust-lang#153018 had a sneaky behavior change in the way tuples are handled and the old behavior wasn't tested.

Consider these tuples:

```rust
((), ());
((), 1);
```

Neither of them is `must_use`, so they are potential candidates for `unused_results`. So the question is whatever said tuples are considered "trivial" and thus if they end up emitting `unused_results` or not.

Here is a comparison table between PRs:
<table>
<tr><td>stable</td><td>After rust-lang#153018</td><td>After this PR</td></tr><tr><td>

```rust
((), ()); // trivial
((), 1); // trivial
```
</td>
<td>

```rust
((), ()); //~ warn: unused_results
((), 1); //~ warn: unused_results
```
</td>
<td>

```rust
((), ()); // trivial
((), 1); //~ warn: unused_results
```
</td>
</tr>
  <tr>
    <td>

tuples are trivial if **any** of their fields are trivial
    </td>
    <td>

tuples are never trivial
    </td>
    <td>

tuples are trivial if **all** of their fields are trivial
    </td>
  </tr>
</table>

…uwer

Rollup of 5 pull requests

Successful merges:

 - #151962 (Fix next-solver ICE on PointeeSized goals)
 - #153161 (Rejig `rustc_with_all_queries!`)
 - #152164 (Lint unused features)
 - #153191 (  don't emit `unused_results` lint for tuples of "trivial" types )
 - #153273 (vec/mod.rs: add missing period in "ie." in docs)

…uwer

Rollup of 5 pull requests

Successful merges:

 - #151962 (Fix next-solver ICE on PointeeSized goals)
 - #153161 (Rejig `rustc_with_all_queries!`)
 - #152164 (Lint unused features)
 - #153191 (  don't emit `unused_results` lint for tuples of "trivial" types )
 - #153273 (vec/mod.rs: add missing period in "ie." in docs)

…uwer

Rollup of 5 pull requests

Successful merges:

 - #151962 (Fix next-solver ICE on PointeeSized goals)
 - #153161 (Rejig `rustc_with_all_queries!`)
 - #152164 (Lint unused features)
 - #153191 (  don't emit `unused_results` lint for tuples of "trivial" types )
 - #153273 (vec/mod.rs: add missing period in "ie." in docs)