Introduce macro sub-namespaces and `macro_use` prelude
This PR implements two mechanisms needed for correct macro name resolution: macro sub-namespace and `macro_use` prelude.
- [macro sub-namespaces][subns-ref]
Macros have two sub-namespaces: one for function-like macro and the other for those in attributes (including custom derive macros). When we're resolving a macro name for function-like macro, we should ignore non-function-like macros, and vice versa.
This helps resolve single-segment macro names because we can (and should, as rustc does) fallback to names in preludes when the name in the current module scope is in different sub-namespace.
- [`macro_use` prelude][prelude-ref]
`#[macro_use]`'d extern crate declarations (including the standard library) bring their macros into scope, but they should not be prioritized over local macros (those defined in place and those explicitly imported).
We have been bringing them into legacy (textual) macro scope, which has the highest precedence in name resolution. This PR introduces the `macro_use` prelude in crate-level `DefMap`s, whose precedence is lower than local macros but higher than the standard library prelude.
The first 3 commits are drive-by fixes/refactors.
Fixes#8828 (prelude)
Fixes#12505 (prelude)
Fixes#12734 (prelude)
Fixes#13683 (prelude)
Fixes#13821 (prelude)
Fixes#13974 (prelude)
Fixes#14254 (namespace)
[subns-ref]: https://doc.rust-lang.org/reference/names/namespaces.html#sub-namespaces
[prelude-ref]: https://doc.rust-lang.org/reference/names/preludes.html#macro_use-prelude
We've already removed non-sysroot proc macro server, which effectively
removed support for Rust <1.64.0, so this removal of fallback path
shouldn't be problem at this point.
More APIs for `la_arena::IdxRange`
```rust
impl<T> ExactSizeIterator for IdxRange<T>;
impl<T> Arena<T> {
pub fn alloc_many<II: IntoIterator<Item = T>>(&mut self, iter: II) -> IdxRange<T>;
}
```
1. There are no currently ways to get `IdxRange` without manually offseting `Idx`. Providing a method for multiple-allocation simplifies this process and makes it less error-prone.
2. `IdxRange: ExactSizeIterator` makes `iter.zip(range).rev()` possible. Since `Zip: DoubleEndedIterator` requires all its arguments to be `ExactSizeIterator`. It also ease the usage for, eg. `len()`.
3. Fixed a typo.
I noticed that `IdxRange::end` may be invalid. Is it good to return `Idx` instead of `RawIdx`?
Fix libs publish branch filter
line-index didn't actually get published from #14733, probably because the branch filter was for main but the main branch is called master here. This fixes the workflow file
I also tweaked the libs readme mostly just so the paths filter would pick up the changes.
This function/lang_item was introduced in #104321 as a temporary workaround of future lowering.
The usage and need for it went away in #104833.
After a bootstrap update, the function itself can be removed from `std`.
Make line-index a lib, use nohash_hasher
These seem like they are not specific to rust-analyzer and could be pulled out to their own libraries. So I did.
https://github.com/azdavis/millet/issues/31
