Merge #9807
9807: Implicit `Sized` bounds r=iDawer a=iDawer
This should close #8984
`hir_ty`:
- Type parameters, associated types and `impl Trait` are `Sized` by deafault except `Self` in a trait.
- Implicit `Sized` bound is added to end of predicate list. It does not check if such bound is present already. Also it does not track the bound is implicit.
- Allowed ambiguous unsize coercion if Chalk returns definite guidance.
- Allowed ambiguous autoderef if Chalk returns definite guidance.
`hir_def`:
- `ItemTree` pretty printing shows `?Sized` bounds.
`HirDisplay`:
- `impl Trait` with weird bounds rendered correctly.
- `Sized`/`?Sized` bounds are not shown if they are default.
### Perf
`./target/rust-analyzer-baseline_8a843113 -q analysis-stats --memory-usage .`
```
Database loaded: 1.63s, 287minstr, 91mb
crates: 38, mods: 741, decls: 15914, fns: 11835
Item Collection: 26.80s, 73ginstr, 338mb
exprs: 318994, ??ty: 398 (0%), ?ty: 435 (0%), !ty: 174
Inference: 50.28s, 116ginstr, 516mb
Total: 77.08s, 189ginstr, 855mb
```
`./target/rust-analyzer-sized-fixed_ambig_coercion-de074fe6 -q analysis-stats --memory-usage .`
```
Database loaded: 1.63s, 287minstr, 91mb
crates: 38, mods: 741, decls: 15914, fns: 11835
Item Collection: 26.95s, 73ginstr, 338mb
exprs: 318994, ??ty: 398 (0%), ?ty: 435 (0%), !ty: 166
Inference: 96.39s, 234ginstr, 543mb
Total: 123.33s, 307ginstr, 881mb
```
Co-authored-by: Dawer <7803845+iDawer@users.noreply.github.com>
baf1494374