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resolve: Simplify collection of traits in scope

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This commit is contained in:
Vadim Petrochenkov 2021-01-06 23:50:02 +03:00
parent 6526e5c772
commit b7071b2353
7 changed files with 141 additions and 163 deletions
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2
compiler/rustc_resolve/src/build_reduced_graph.rs
View File

@ -115,7 +115,7 @@ fn nearest_parent_mod(&mut self, def_id: DefId) -> Module<'a> {
self.get_module(parent_id)
}
crate fn get_module(&mut self, def_id: DefId) -> Module<'a> {
pub fn get_module(&mut self, def_id: DefId) -> Module<'a> {
// If this is a local module, it will be in `module_map`, no need to recalculate it.
if let Some(def_id) = def_id.as_local() {
return self.module_map[&def_id];

72
compiler/rustc_resolve/src/late.rs
View File

@ -14,7 +14,6 @@
use rustc_ast::ptr::P;
use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
use rustc_ast::*;
use rustc_ast::{unwrap_or, walk_list};
use rustc_ast_lowering::ResolverAstLowering;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_errors::DiagnosticId;
@ -1911,7 +1910,7 @@ fn smart_resolve_path_fragment(
// it needs to be added to the trait map.
if ns == ValueNS {
let item_name = path.last().unwrap().ident;
let traits = self.get_traits_containing_item(item_name, ns);
let traits = self.traits_in_scope(item_name, ns);
self.r.trait_map.insert(id, traits);
}
@ -2372,12 +2371,12 @@ fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &'ast Expr) {
// field, we need to add any trait methods we find that match
// the field name so that we can do some nice error reporting
// later on in typeck.
let traits = self.get_traits_containing_item(ident, ValueNS);
let traits = self.traits_in_scope(ident, ValueNS);
self.r.trait_map.insert(expr.id, traits);
}
ExprKind::MethodCall(ref segment, ..) => {
debug!("(recording candidate traits for expr) recording traits for {}", expr.id);
let traits = self.get_traits_containing_item(segment.ident, ValueNS);
let traits = self.traits_in_scope(segment.ident, ValueNS);
self.r.trait_map.insert(expr.id, traits);
}
_ => {
@ -2386,64 +2385,13 @@ fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &'ast Expr) {
}
}
fn get_traits_containing_item(
&mut self,
mut ident: Ident,
ns: Namespace,
) -> Vec<TraitCandidate> {
debug!("(getting traits containing item) looking for '{}'", ident.name);
let mut found_traits = Vec::new();
// Look for the current trait.
if let Some((module, _)) = self.current_trait_ref {
if self
.r
.resolve_ident_in_module(
ModuleOrUniformRoot::Module(module),
ident,
ns,
&self.parent_scope,
false,
module.span,
)
.is_ok()
{
let def_id = module.def_id().unwrap();
found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
}
}
ident.span = ident.span.normalize_to_macros_2_0();
let mut search_module = self.parent_scope.module;
loop {
self.r.get_traits_in_module_containing_item(
ident,
ns,
search_module,
&mut found_traits,
&self.parent_scope,
);
let mut span_data = ident.span.data();
search_module = unwrap_or!(
self.r.hygienic_lexical_parent(search_module, &mut span_data.ctxt),
break
);
ident.span = span_data.span();
}
if let Some(prelude) = self.r.prelude {
if !search_module.no_implicit_prelude {
self.r.get_traits_in_module_containing_item(
ident,
ns,
prelude,
&mut found_traits,
&self.parent_scope,
);
}
}
found_traits
fn traits_in_scope(&mut self, ident: Ident, ns: Namespace) -> Vec<TraitCandidate> {
self.r.traits_in_scope(
self.current_trait_ref.as_ref().map(|(module, _)| *module),
&self.parent_scope,
ident.span.ctxt(),
Some((ident.name, ns)),
)
}
}

131
compiler/rustc_resolve/src/lib.rs
View File

@ -44,9 +44,9 @@
use rustc_metadata::creader::{CStore, CrateLoader};
use rustc_middle::hir::exports::ExportMap;
use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
use rustc_middle::span_bug;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
use rustc_middle::{bug, span_bug};
use rustc_session::lint;
use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
use rustc_session::Session;
@ -1477,52 +1477,79 @@ pub fn resolve_crate(&mut self, krate: &Crate) {
self.crate_loader.postprocess(krate);
}
fn get_traits_in_module_containing_item(
pub fn traits_in_scope(
&mut self,
ident: Ident,
ns: Namespace,
module: Module<'a>,
found_traits: &mut Vec<TraitCandidate>,
current_trait: Option<Module<'a>>,
parent_scope: &ParentScope<'a>,
ctxt: SyntaxContext,
assoc_item: Option<(Symbol, Namespace)>,
) -> Vec<TraitCandidate> {
let mut found_traits = Vec::new();
if let Some(module) = current_trait {
if self.trait_may_have_item(Some(module), assoc_item) {
let def_id = module.def_id().unwrap();
found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
}
}
self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
match scope {
Scope::Module(module) => {
this.traits_in_module(module, assoc_item, &mut found_traits);
}
Scope::StdLibPrelude => {
if let Some(module) = this.prelude {
this.traits_in_module(module, assoc_item, &mut found_traits);
}
}
Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
_ => unreachable!(),
}
None::<()>
});
found_traits
}
fn traits_in_module(
&mut self,
module: Module<'a>,
assoc_item: Option<(Symbol, Namespace)>,
found_traits: &mut Vec<TraitCandidate>,
) {
assert!(ns == TypeNS || ns == ValueNS);
module.ensure_traits(self);
let traits = module.traits.borrow();
for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
// Traits have pseudo-modules that can be used to search for the given ident.
if let Some(module) = binding.module() {
let mut ident = ident;
if ident.span.glob_adjust(module.expansion, binding.span).is_none() {
continue;
}
if self
.resolve_ident_in_module_unadjusted(
ModuleOrUniformRoot::Module(module),
ident,
ns,
parent_scope,
false,
module.span,
)
.is_ok()
{
let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
let trait_def_id = module.def_id().unwrap();
found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
}
} else if let Res::Def(DefKind::TraitAlias, _) = binding.res() {
// For now, just treat all trait aliases as possible candidates, since we don't
// know if the ident is somewhere in the transitive bounds.
let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
let trait_def_id = binding.res().def_id();
found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
} else {
bug!("candidate is not trait or trait alias?")
for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
if self.trait_may_have_item(trait_binding.module(), assoc_item) {
let def_id = trait_binding.res().def_id();
let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
found_traits.push(TraitCandidate { def_id, import_ids });
}
}
}
// List of traits in scope is pruned on best effort basis. We reject traits not having an
// associated item with the given name and namespace (if specified). This is a conservative
// optimization, proper hygienic type-based resolution of associated items is done in typeck.
// We don't reject trait aliases (`trait_module == None`) because we don't have access to their
// associated items.
fn trait_may_have_item(
&mut self,
trait_module: Option<Module<'a>>,
assoc_item: Option<(Symbol, Namespace)>,
) -> bool {
match (trait_module, assoc_item) {
(Some(trait_module), Some((name, ns))) => {
self.resolutions(trait_module).borrow().iter().any(|resolution| {
let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
assoc_ns == ns && assoc_ident.name == name
})
}
_ => true,
}
}
fn find_transitive_imports(
&mut self,
mut kind: &NameBindingKind<'_>,
@ -3227,34 +3254,6 @@ fn extern_prelude_get(
})
}
/// This is equivalent to `get_traits_in_module_containing_item`, but without filtering by the associated item.
///
/// This is used by rustdoc for intra-doc links.
pub fn traits_in_scope(&mut self, module_id: DefId) -> Vec<TraitCandidate> {
let module = self.get_module(module_id);
module.ensure_traits(self);
let traits = module.traits.borrow();
let to_candidate =
|this: &mut Self, &(trait_name, binding): &(Ident, &NameBinding<'_>)| TraitCandidate {
def_id: binding.res().def_id(),
import_ids: this.find_transitive_imports(&binding.kind, trait_name),
};
let mut candidates: Vec<_> =
traits.as_ref().unwrap().iter().map(|x| to_candidate(self, x)).collect();
if let Some(prelude) = self.prelude {
if !module.no_implicit_prelude {
prelude.ensure_traits(self);
candidates.extend(
prelude.traits.borrow().as_ref().unwrap().iter().map(|x| to_candidate(self, x)),
);
}
}
candidates
}
/// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
/// isn't something that can be returned because it can't be made to live that long,
/// and also it's a private type. Fortunately rustdoc doesn't need to know the error,

9
src/librustdoc/passes/collect_intra_doc_links.rs
View File

@ -19,7 +19,7 @@
builtin::{BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS},
Lint,
};
use rustc_span::hygiene::MacroKind;
use rustc_span::hygiene::{MacroKind, SyntaxContext};
use rustc_span::symbol::Ident;
use rustc_span::symbol::Symbol;
use rustc_span::DUMMY_SP;
@ -770,7 +770,12 @@ fn traits_implemented_by(cx: &DocContext<'_>, type_: DefId, module: DefId) -> Fx
let mut cache = cx.module_trait_cache.borrow_mut();
let in_scope_traits = cache.entry(module).or_insert_with(|| {
cx.enter_resolver(|resolver| {
resolver.traits_in_scope(module).into_iter().map(|candidate| candidate.def_id).collect()
let parent_scope = &ParentScope::module(resolver.get_module(module), resolver);
resolver
.traits_in_scope(None, parent_scope, SyntaxContext::root(), None)
.into_iter()
.map(|candidate| candidate.def_id)
.collect()
})
});

53
src/test/ui/hygiene/traits-in-scope.rs Normal file
View File

@ -0,0 +1,53 @@
// Macros with def-site hygiene still bring traits into scope.
// It is not clear whether this is desirable behavior or not.
// It is also not clear how to prevent it if it is not desirable.
// check-pass
#![feature(decl_macro)]
#![feature(trait_alias)]
mod traits {
pub trait Trait1 {
fn simple_import(&self) {}
}
pub trait Trait2 {
fn renamed_import(&self) {}
}
pub trait Trait3 {
fn underscore_import(&self) {}
}
pub trait Trait4 {
fn trait_alias(&self) {}
}
impl Trait1 for () {}
impl Trait2 for () {}
impl Trait3 for () {}
impl Trait4 for () {}
}
macro m1() {
use traits::Trait1;
}
macro m2() {
use traits::Trait2 as Alias;
}
macro m3() {
use traits::Trait3 as _;
}
macro m4() {
trait Alias = traits::Trait4;
}
fn main() {
m1!();
m2!();
m3!();
m4!();
().simple_import();
().renamed_import();
().underscore_import();
().trait_alias();
}

10
src/test/ui/underscore-imports/hygiene.rs
View File

@ -1,5 +1,6 @@
// Make sure that underscore imports have the same hygiene considerations as
// other imports.
// Make sure that underscore imports have the same hygiene considerations as other imports.
// check-pass
#![feature(decl_macro)]
@ -7,7 +8,6 @@ mod x {
pub use std::ops::Deref as _;
}
macro glob_import() {
pub use crate::x::*;
}
@ -35,6 +35,6 @@ fn main() {
use crate::z::*;
glob_import!();
underscore_import!();
(&()).deref(); //~ ERROR no method named `deref`
(&mut ()).deref_mut(); //~ ERROR no method named `deref_mut`
(&()).deref();
(&mut ()).deref_mut();
}

27
src/test/ui/underscore-imports/hygiene.stderr
View File

@ -1,27 +0,0 @@
error[E0599]: no method named `deref` found for reference `&()` in the current scope
--> $DIR/hygiene.rs:38:11
|
LL | (&()).deref();
| ^^^^^ method not found in `&()`
|
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
LL | use std::ops::Deref;
|
error[E0599]: no method named `deref_mut` found for mutable reference `&mut ()` in the current scope
--> $DIR/hygiene.rs:39:15
|
LL | (&mut ()).deref_mut();
| ^^^^^^^^^ method not found in `&mut ()`
|
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
LL | use std::ops::DerefMut;
|
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0599`.