feat: ignored and disabled macro expansion
Supersedes #15117, I was having some conflicts after a rebase and since I didn't remember much of it I started clean instead.
The end result is pretty much the same as the linked PR, but instead of proc macro lookups, I marked the expanders that explicitly cannot be expanded and we shouldn't even attempt to do so.
## Unresolved questions
- [ ] I introduced a `DISABLED_ID` next to `DUMMY_ID` in `hir-expand`'s `ProcMacroExpander`, that is effectively exactly the same thing with slightly different semantics, dummy macros are not (yet) expanded probably due to errors, while not expanding disabled macros is part of the usual flow. I'm not sure if it's the right way to handle this, I also thought of just adding a flag instead of replacing the macro ID, so that the disabled macro can still be expanded for any reason if needed.
fix: Correctly set and mark the proc-macro spans
This slows down analysis by 2-3s on self for me unfortunately (~2.5% slowdown)
Noisy diff due to two simple refactoring in the first 2 commits. Relevant changes are [7d762d1](7d762d18ed) and [1e1113c](1e1113cf5f) which introduce def site spans and correct marking for proc-macros respectively.
fix: Update metavariable expression implementation
Fixes https://github.com/rust-lang/rust-analyzer/issues/16154
This duplicates behavior of that before and after PR https://github.com/rust-lang/rust/pull/117050 based on the toolchain version. There are some 1.76 nightlies that are still broken (any before that PR basically) but fetching and storing the commit makes little sense to me (opposed to the toolchain version).
Fixes#16110.
The way rust desugars doc comments when expanding macros
is rendering it as raw strings delimited with hashes.
Rust-analyzer wasn't aware of this, so the desugared doc
comments wouldn't match correctly when on the LHS of macro
declarations.
This PR fixes this by porting the code used by rustc: 4cfdbd328b/compiler/rustc_ast/src/tokenstream.rs (L6837)
internal: Record import origins in ItemScope and PerNS
This records the import items definitions come from in the module scope (as well as what an import resolves to in an ItemScope). It does ignore glob imports as thats a lot more work for little to no gain, glob imports act as if the importing items are "inlined" into the scope which suffices for almost all use cases I believe (to my knowledge, attributes on them have little effect).
There is still a lot of work needed to make this available to the IDE layer, but this lays out the ground work for havin IDE layer support.
cc https://github.com/rust-lang/rust-analyzer/issues/14079
