Have Derive Attribute share a token tree with it's proc macros.
The goal of this PR is to stop creating a token tree for each derive proc macro.
This is done by giving the derive proc macros an id to its parent derive element.
From running the analysis stat on the rust analyzer project I did see a small memory decrease.
```
Inference: 42.80s, 362ginstr, 591mb
MIR lowering: 8.67s, 67ginstr, 291mb
Mir failed bodies: 18 (0%)
Data layouts: 85.81ms, 609minstr, 8mb
Failed data layouts: 135 (6%)
Const evaluation: 440.57ms, 5235minstr, 13mb
Failed const evals: 1 (0%)
Total: 64.16s, 552ginstr, 1731mb
```
After Change
```
Inference: 40.32s, 340ginstr, 593mb
MIR lowering: 7.95s, 62ginstr, 292mb
Mir failed bodies: 18 (0%)
Data layouts: 87.97ms, 591minstr, 8mb
Failed data layouts: 135 (6%)
Const evaluation: 433.38ms, 5226minstr, 14mb
Failed const evals: 1 (0%)
Total: 60.49s, 523ginstr, 1680mb
```
Currently this breaks the expansion for the actual derive attribute.
## TODO
- [x] Pick a better name for the function `smart_macro_arg`
Add more methods for resolving definitions from AST to their corresponding HIR types
In order to be able to add these methods with consistent naming I had to also rename two existing methods that would otherwise be conflicting/confusing:
`Semantics::to_module_def(&self, file: FileId) -> Option<Module>` (before)
`Semantics::file_to_module_def(&self, file: FileId) -> Option<Module>` (after)
`Semantics::to_module_defs(&self, file: FileId) -> impl Iterator<Item = Module>` (before)
`Semantics::file_to_module_defs(&self, file: FileId) -> impl Iterator<Item = Module>` (after)
(the PR is motivated by an outside use of the `ra_ap_hir` crate that would benefit from being able to walk a `hir::Function`'s AST, resolving its exprs/stmts/items to their HIR equivalents)
Export `SemanticsImpl` from `ra_ap_hir` crate, since it's already exposed via `Semantics.deref()`
The `SemanticsImpl` type is already de-facto exposed via `<Semantics as Deref>::Target`.
By not being part of the public crate interface it however doesn't get included in the documentation, resulting in a massive blind spot when it comes to `ra_ap_hir`'s type resolution APIs.
Add public function for resolving callable AST exprs to their HIR equivalents
(the PR is motivated by an outside use of the `ra_ap_hir` crate that would benefit from being able to walk a `hir::Function`'s AST, resolving callable exprs within to their HIR equivalents)
Derive `PartialEq`, `Eq` & `Hash` for `hir::Param`
Since `hir::SelfParam`, as well as all members of `hir::Param` already implement `PartialEq`, `Eq` & `Hash` it seems reasonable to also make `hir::Param` implement those.
(the change is motivated by an outside use of the `ra_ap_hir` crate that would benefit from being able to collect params in a `HashSet`)
