bjoernager/rust
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Remember names of cfg-ed out items to mention them in diagnostics

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`#[cfg]`s are frequently used to gate crate content behind cargo
features. This can lead to very confusing errors when features are
missing. For example, `serde` doesn't have the `derive` feature by
default. Therefore, `serde::Serialize` fails to resolve with a generic
error, even though the macro is present in the docs.

This commit adds a list of all stripped item names to metadata. This is
filled during macro expansion and then, through a fed query, persisted
in metadata. The downstream resolver can then access the metadata to
look at possible candidates for mentioning in the errors.

This slightly increases metadata (800k->809k for the feature-heavy
windows crate), but not enough to really matter.
This commit is contained in:
Nilstrieb 2023-03-10 22:39:14 +01:00
parent 642c92e630
commit a647ba250a
30 changed files with 599 additions and 84 deletions
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4
compiler/rustc_expand/src/base.rs
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@ -947,6 +947,8 @@ pub trait ResolverExpand {
/// HIR proc macros items back to their harness items.
fn declare_proc_macro(&mut self, id: NodeId);
fn append_stripped_cfg_item(&mut self, parent_node: NodeId, name: Ident, cfg: ast::MetaItem);
/// Tools registered with `#![register_tool]` and used by tool attributes and lints.
fn registered_tools(&self) -> &RegisteredTools;
}
@ -965,7 +967,7 @@ pub trait LintStoreExpand {
type LintStoreExpandDyn<'a> = Option<&'a (dyn LintStoreExpand + 'a)>;
#[derive(Clone, Default)]
#[derive(Debug, Clone, Default)]
pub struct ModuleData {
/// Path to the module starting from the crate name, like `my_crate::foo::bar`.
pub mod_path: Vec<Ident>,