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Auto merge of #14610 - lowr:fix/hygiene-for-meta-item, r=Veykril

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fix: Resolve `$crate` in derive paths

Paths in derive meta item list may contain any kind of paths, including those that start with `$crate` generated by macros. We need to take hygiene into account when we lower paths in the list.

This issue was identified while investigating #14607, though this patch doesn't fix the broken trait resolution.
This commit is contained in:
bors 2023-04-22 09:36:38 +00:00
commit 34ebb30e84
3 changed files with 76 additions and 17 deletions
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39
crates/hir-def/src/nameres/collector.rs
View File

@ -14,6 +14,7 @@
builtin_attr_macro::find_builtin_attr,
builtin_derive_macro::find_builtin_derive,
builtin_fn_macro::find_builtin_macro,
hygiene::Hygiene,
name::{name, AsName, Name},
proc_macro::ProcMacroExpander,
ExpandResult, ExpandTo, HirFileId, InFile, MacroCallId, MacroCallKind, MacroCallLoc,
@ -122,6 +123,7 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: DefMap, tree_id: T
from_glob_import: Default::default(),
skip_attrs: Default::default(),
is_proc_macro,
hygienes: FxHashMap::default(),
};
if tree_id.is_block() {
collector.seed_with_inner(tree_id);
@ -269,6 +271,12 @@ struct DefCollector<'a> {
/// This also stores the attributes to skip when we resolve derive helpers and non-macro
/// non-builtin attributes in general.
skip_attrs: FxHashMap<InFile<ModItem>, AttrId>,
/// `Hygiene` cache, because `Hygiene` construction is expensive.
///
/// Almost all paths should have been lowered to `ModPath` during `ItemTree` construction.
/// However, `DefCollector` still needs to lower paths in attributes, in particular those in
/// derive meta item list.
hygienes: FxHashMap<HirFileId, Hygiene>,
}
impl DefCollector<'_> {
@ -312,13 +320,15 @@ fn seed_with_top_level(&mut self) {
}
if *attr_name == hir_expand::name![feature] {
let features =
attr.parse_path_comma_token_tree().into_iter().flatten().filter_map(
|feat| match feat.segments() {
[name] => Some(name.to_smol_str()),
_ => None,
},
);
let hygiene = &Hygiene::new_unhygienic();
let features = attr
.parse_path_comma_token_tree(self.db.upcast(), hygiene)
.into_iter()
.flatten()
.filter_map(|feat| match feat.segments() {
[name] => Some(name.to_smol_str()),
_ => None,
});
self.def_map.unstable_features.extend(features);
}
@ -1224,7 +1234,19 @@ fn resolve_macros(&mut self) -> ReachedFixedPoint {
};
let ast_id = ast_id.with_value(ast_adt_id);
match attr.parse_path_comma_token_tree() {
let extend_unhygenic;
let hygiene = if file_id.is_macro() {
self.hygienes
.entry(file_id)
.or_insert_with(|| Hygiene::new(self.db.upcast(), file_id))
} else {
// Avoid heap allocation (`Hygiene` embraces `Arc`) and hash map entry
// when we're in an oridinary (non-macro) file.
extend_unhygenic = Hygiene::new_unhygienic();
&extend_unhygenic
};
match attr.parse_path_comma_token_tree(self.db.upcast(), hygiene) {
Some(derive_macros) => {
let mut len = 0;
for (idx, path) in derive_macros.enumerate() {
@ -2212,6 +2234,7 @@ fn do_collect_defs(db: &dyn DefDatabase, def_map: DefMap) -> DefMap {
from_glob_import: Default::default(),
skip_attrs: Default::default(),
is_proc_macro: false,
hygienes: FxHashMap::default(),
};
collector.seed_with_top_level();
collector.collect();

23
crates/hir-def/src/nameres/tests/macros.rs
View File

@ -664,6 +664,29 @@ macro_rules! foo {
);
}
#[test]
fn macro_dollar_crate_is_correct_in_derive_meta() {
let map = compute_crate_def_map(
r#"
//- minicore: derive, clone
//- /main.rs crate:main deps:lib
lib::foo!();
//- /lib.rs crate:lib
#[macro_export]
macro_rules! foo {
() => {
#[derive($crate::Clone)]
struct S;
}
}
pub use core::clone::Clone;
"#,
);
assert_eq!(map.modules[map.root].scope.impls().len(), 1);
}
#[test]
fn expand_derive() {
let map = compute_crate_def_map(

31
crates/hir-expand/src/attrs.rs
View File

@ -12,8 +12,7 @@
use crate::{
db::ExpandDatabase,
hygiene::Hygiene,
mod_path::{ModPath, PathKind},
name::AsName,
mod_path::ModPath,
tt::{self, Subtree},
InFile,
};
@ -267,7 +266,11 @@ pub fn token_tree_value(&self) -> Option<&Subtree> {
}
/// Parses this attribute as a token tree consisting of comma separated paths.
pub fn parse_path_comma_token_tree(&self) -> Option<impl Iterator<Item = ModPath> + '_> {
pub fn parse_path_comma_token_tree<'a>(
&'a self,
db: &'a dyn ExpandDatabase,
hygiene: &'a Hygiene,
) -> Option<impl Iterator<Item = ModPath> + 'a> {
let args = self.token_tree_value()?;
if args.delimiter.kind != DelimiterKind::Parenthesis {
@ -276,15 +279,25 @@ pub fn parse_path_comma_token_tree(&self) -> Option<impl Iterator<Item = ModPath
let paths = args
.token_trees
.split(|tt| matches!(tt, tt::TokenTree::Leaf(tt::Leaf::Punct(Punct { char: ',', .. }))))
.filter_map(|tts| {
.filter_map(move |tts| {
if tts.is_empty() {
return None;
}
let segments = tts.iter().filter_map(|tt| match tt {
tt::TokenTree::Leaf(tt::Leaf::Ident(id)) => Some(id.as_name()),
_ => None,
});
Some(ModPath::from_segments(PathKind::Plain, segments))
// FIXME: This is necessarily a hack. It'd be nice if we could avoid allocation here.
let subtree = tt::Subtree {
delimiter: tt::Delimiter::unspecified(),
token_trees: tts.into_iter().cloned().collect(),
};
let (parse, _) =
mbe::token_tree_to_syntax_node(&subtree, mbe::TopEntryPoint::MetaItem);
let meta = ast::Meta::cast(parse.syntax_node())?;
// Only simple paths are allowed.
if meta.eq_token().is_some() || meta.expr().is_some() || meta.token_tree().is_some()
{
return None;
}
let path = meta.path()?;
ModPath::from_src(db, path, hygiene)
});
Some(paths)