Apply visit_path to import prefixes by default
Overriding `visit_path` is not enough to visit all paths, some import prefixes are not visited and `visit_path_list_item` need to be overridden as well. This PR removes this catch, it should be less error prone this way. Also, the prefix is visited once now, not repeatedly for each path list item.
r? @eddyb
Increase spacing in error format for readability.
Two small tweaks that seem to help readability quite a bit:
* Add spacing header<->snippet, but use the |> on the side for visual consistency
* Fix#33819
* Fix#33763
* Move format-sensitive test (issue-26480 in cfail) to ui test
r? @nikomatsakis
Perform `cfg` attribute processing during macro expansion and fix bugs
This PR refactors `cfg` attribute processing and fixes bugs. More specifically:
- It merges gated feature checking for stmt/expr attributes, `cfg_attr` processing, and `cfg` processing into a single fold.
- This allows feature gated `cfg` variables to be used in `cfg_attr` on unconfigured items. All other feature gated attributes can already be used on unconfigured items.
- It performs `cfg` attribute processing during macro expansion instead of after expansion so that macro-expanded items are configured the same as ordinary items. In particular, to match their non-expanded counterparts,
- macro-expanded unconfigured macro invocations are no longer expanded,
- macro-expanded unconfigured macro definitions are no longer usable, and
- feature gated `cfg` variables on macro-expanded macro definitions/invocations are now errors.
This is a [breaking-change]. For example, the following would break:
```rust
macro_rules! m {
() => {
#[cfg(attr)]
macro_rules! foo { () => {} }
foo!(); // This will be an error
macro_rules! bar { () => { fn f() {} } }
#[cfg(attr)] bar!(); // This will no longer be expanded ...
fn g() { f(); } // ... so that `f` will be unresolved.
#[cfg(target_thread_local)] // This will be a gated feature error
macro_rules! baz { () => {} }
}
}
m!();
```
r? @nrc
This makes the \"shadowing labels\" warning *not* print the entire loop as a span, but only the lifetime.
Also makes #31719 go away, but does not fix its root cause (the span of the expanded loop is still wonky, but not used anymore).
Make sure that macros that didn't pass LHS checking are not expanded.
This avoid duplicate errors for things like invalid fragment specifiers, or
parsing errors for ambiguous macros.
This makes the "shadowing labels" warning *not* print the entire loop
as a span, but only the lifetime.
Also makes #31719 go away, but does not fix its root cause (the span
of the expanded loop is still wonky, but not used anymore).
