internal: Implement parent-child relation for `SourceRoot`s
This commit adds the said relation by keeping a map of type `FxHashMap<SourceRootId,Option<SourceRootId>>` inside the `GlobalState`. Its primary use case is reading `rust-analyzer.toml`(#13529) files that can be placed in every local source root. As a config will be found by traversing this "tree" we need the parent information for every local source root. This commit omits defining this relation for library source roots entirely.
This commit adds the said relation by keeping a map of type `FxHashMap<SourceRootId,Option<SourceRootId>>`
inside the `GlobalState`. Its primary use case is reading the rust-analyzer.toml files that can be
placed under every local source root. As a config will be found by traversing this "tree" we need the parent information
for every local source root. This commit omits defining this relation for library source roots entirely.
internal: Compute syntax validation errors on demand
The LRU cache causes us to re-parse trees quite often, yet we don't use the validation errors at all. With this we push calculating them off to the caller who is interested in them.
Commit 6a06f6f72 (Deduplicate reference search results, 2022-11-07) deduplicates references
within each definition.
There is an edge case when requesting references of a macro argument. Apparently, our
descend_into_macros() stanza in references.rs produces a cartesian product of
- references inside the macro times
- times references outside the macro.
Since the above deduplication only applies to the references within a single definition, we
return them all, leading to many redundant references.
Work around this by deduplicating definitions as well. Perhaps there is a better fix to not
produce this cartesian product in the first place; but I think at least for definitions the
problem would remain; a macro can contain multiple definitions of the same name, but since the
navigation target will be the unresolved location, it's the same for all of them.
We can't use unique() because we don't want to drop references that don't have a declaration
(though I dont' have an example for this case).
I discovered this working with the "bitflags" macro from the crate of the same name.
Fixes#16357
