This fixes a bug where labels inside macros were not resolved, but more importantly this prepares us to a future where we have hygiene, and textual equivalence isn't enough to resolve identifiers.
Previously some expansions were not cached, but were cached in the expansion cache, which caused panics when later queries tried to lookup the node from the expansion cache.
The previous analysis was top-down, and worked on a single file (expanding macros). The new analysis is bottom-up, starting from the diagnostics and climbing up the syntax and module tree.
While this is more efficient (and in fact, efficiency was the motivating reason to work on this), unfortunately the code was already fast enough. But luckily, it also fixes a correctness problem: outline parent modules' attributes were not respected for the previous analysis. Case lints specifically did their own analysis to accommodate that, but it was limited to only them. The new analysis works on all kinds of lints, present and future.
It was basically impossible to fix the old analysis without rewriting it because navigating the module hierarchy must come bottom-up, and if we already have a bottom-up analysis (including syntax analysis because modules can be nested in other syntax elements, including macros), it makes sense to use only this kind of analysis.
Few other bugs (not fundamental ti the previous analysis) are also fixed, e.g. overwriting of lint levels (i.e. `#[allow(lint)] mod foo { #[warn(lint)] mod bar; }`.
This commit makes the "Wrap return type in Result" assist prefer type aliases of standard library
type when the are in scope, use at least one generic parameter, and have the name "Result".
The last restriction was made in an attempt to avoid false assumptions about which type the
user is referring to, but that might be overly strict. We could also do something like this, in
order of priority:
* Use the alias named "Result".
* Use any alias if only a single one is in scope, otherwise:
* Use the standard library type.
This is easy to add if others feel differently that is appropriate, just let me know.
This avoids the need to analyze the file when we are not inside a macro call.
This is especially important for the optimization in the next commit(s), as there the common case will be to descent into macros but then not analyze.
Filter builtin macro expansion
This PR adds a filter on the types of built in macros that are allowed to be expanded.
Currently, This list of allowed macros contains, `stringify, cfg, core_panic, std_panic, concat, concat_bytes, include, include_str, include_bytes, env` and `option_env`.
Fixes#14177
When viewing traces, it's slightly confusing when the span name doesn't
match the function name. Ensure the names are consistent.
(It might be worth moving most of these to use #[tracing::instrument]
so the name can never go stale. @davidbarsky suggested that is marginally
slower, so I've just done the simple change here.)
