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fuchsia / third_party / rust / a8aa5114bf13d9c6b2b870c5bf63eab8e70a0018 / . / src / librustc_resolve / lib.rs
blob: 74f68e514712623af4f8eda8d66831f1b706c873 [file] [log] [blame]
//! This crate is responsible for the part of name resolution that doesn't require type checker.
//!
//! Module structure of the crate is built here.
//! Paths in macros, imports, expressions, types, patterns are resolved here.
//! Label names are resolved here as well.
//!
//! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
//! Lifetime names are resolved in `librustc/middle/resolve_lifetime.rs`.
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
#![feature(inner_deref)]
#![feature(crate_visibility_modifier)]
#![feature(label_break_value)]
#![feature(mem_take)]
#![feature(nll)]
#![recursion_limit="256"]
pub use rustc::hir::def::{Namespace, PerNS};
use Determinacy::*;
use rustc::hir::map::Definitions;
use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
use rustc::middle::cstore::CrateStore;
use rustc::session::Session;
use rustc::lint;
use rustc::hir::def::{self, DefKind, PartialRes, CtorKind, CtorOf, NonMacroAttrKind, ExportMap};
use rustc::hir::def::Namespace::*;
use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
use rustc::hir::{TraitMap, GlobMap};
use rustc::ty;
use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
use rustc::span_bug;
use rustc_metadata::creader::CrateLoader;
use rustc_metadata::cstore::CStore;
use syntax::ext::hygiene::{ExpnId, Transparency, SyntaxContext};
use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
use syntax::ext::base::{SyntaxExtension, MacroKind, SpecialDerives};
use syntax::symbol::{kw, sym};
use syntax::visit::{self, Visitor};
use syntax::attr;
use syntax::ast::{CRATE_NODE_ID, Crate};
use syntax::ast::{ItemKind, Path};
use syntax::{struct_span_err, unwrap_or};
use syntax_pos::{Span, DUMMY_SP};
use errors::{Applicability, DiagnosticBuilder};
use log::debug;
use std::cell::{Cell, RefCell};
use std::{cmp, fmt, iter, ptr};
use std::collections::BTreeSet;
use rustc_data_structures::ptr_key::PtrKey;
use rustc_data_structures::sync::Lrc;
use diagnostics::{Suggestion, ImportSuggestion};
use diagnostics::{find_span_of_binding_until_next_binding, extend_span_to_previous_binding};
use late::{PathSource, Rib, RibKind::*};
use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
use macros::{LegacyBinding, LegacyScope};
type Res = def::Res<NodeId>;
pub mod error_codes;
mod diagnostics;
mod late;
mod macros;
mod check_unused;
mod build_reduced_graph;
mod resolve_imports;
const KNOWN_TOOLS: &[Name] = &[sym::clippy, sym::rustfmt];
enum Weak {
Yes,
No,
}
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum Determinacy {
Determined,
Undetermined,
}
impl Determinacy {
fn determined(determined: bool) -> Determinacy {
if determined { Determinacy::Determined } else { Determinacy::Undetermined }
}
}
/// A specific scope in which a name can be looked up.
/// This enum is currently used only for early resolution (imports and macros),
/// but not for late resolution yet.
#[derive(Clone, Copy)]
enum Scope<'a> {
DeriveHelpers,
MacroRules(LegacyScope<'a>),
CrateRoot,
Module(Module<'a>),
MacroUsePrelude,
BuiltinAttrs,
LegacyPluginHelpers,
ExternPrelude,
ToolPrelude,
StdLibPrelude,
BuiltinTypes,
}
/// Names from different contexts may want to visit different subsets of all specific scopes
/// with different restrictions when looking up the resolution.
/// This enum is currently used only for early resolution (imports and macros),
/// but not for late resolution yet.
enum ScopeSet {
/// All scopes with the given namespace.
All(Namespace, /*is_import*/ bool),
/// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
AbsolutePath(Namespace),
/// All scopes with macro namespace and the given macro kind restriction.
Macro(MacroKind),
}
/// Everything you need to know about a name's location to resolve it.
/// Serves as a starting point for the scope visitor.
/// This struct is currently used only for early resolution (imports and macros),
/// but not for late resolution yet.
#[derive(Clone, Copy, Debug)]
pub struct ParentScope<'a> {
module: Module<'a>,
expansion: ExpnId,
legacy: LegacyScope<'a>,
derives: &'a [ast::Path],
}
impl<'a> ParentScope<'a> {
/// Creates a parent scope with the passed argument used as the module scope component,
/// and other scope components set to default empty values.
pub fn module(module: Module<'a>) -> ParentScope<'a> {
ParentScope {
module,
expansion: ExpnId::root(),
legacy: LegacyScope::Empty,
derives: &[],
}
}
}
#[derive(Eq)]
struct BindingError {
name: Name,
origin: BTreeSet<Span>,
target: BTreeSet<Span>,
could_be_path: bool
}
impl PartialOrd for BindingError {
fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for BindingError {
fn eq(&self, other: &BindingError) -> bool {
self.name == other.name
}
}
impl Ord for BindingError {
fn cmp(&self, other: &BindingError) -> cmp::Ordering {
self.name.cmp(&other.name)
}
}
enum ResolutionError<'a> {
/// Error E0401: can't use type or const parameters from outer function.
GenericParamsFromOuterFunction(Res),
/// Error E0403: the name is already used for a type or const parameter in this generic
/// parameter list.
NameAlreadyUsedInParameterList(Name, Span),
/// Error E0407: method is not a member of trait.
MethodNotMemberOfTrait(Name, &'a str),
/// Error E0437: type is not a member of trait.
TypeNotMemberOfTrait(Name, &'a str),
/// Error E0438: const is not a member of trait.
ConstNotMemberOfTrait(Name, &'a str),
/// Error E0408: variable `{}` is not bound in all patterns.
VariableNotBoundInPattern(&'a BindingError),
/// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
VariableBoundWithDifferentMode(Name, Span),
/// Error E0415: identifier is bound more than once in this parameter list.
IdentifierBoundMoreThanOnceInParameterList(&'a str),
/// Error E0416: identifier is bound more than once in the same pattern.
IdentifierBoundMoreThanOnceInSamePattern(&'a str),
/// Error E0426: use of undeclared label.
UndeclaredLabel(&'a str, Option<Name>),
/// Error E0429: `self` imports are only allowed within a `{ }` list.
SelfImportsOnlyAllowedWithin,
/// Error E0430: `self` import can only appear once in the list.
SelfImportCanOnlyAppearOnceInTheList,
/// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
SelfImportOnlyInImportListWithNonEmptyPrefix,
/// Error E0433: failed to resolve.
FailedToResolve { label: String, suggestion: Option<Suggestion> },
/// Error E0434: can't capture dynamic environment in a fn item.
CannotCaptureDynamicEnvironmentInFnItem,
/// Error E0435: attempt to use a non-constant value in a constant.
AttemptToUseNonConstantValueInConstant,
/// Error E0530: `X` bindings cannot shadow `Y`s.
BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
/// Error E0128: type parameters with a default cannot use forward-declared identifiers.
ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
/// Error E0671: const parameter cannot depend on type parameter.
ConstParamDependentOnTypeParam,
}
// A minimal representation of a path segment. We use this in resolve because
// we synthesize 'path segments' which don't have the rest of an AST or HIR
// `PathSegment`.
#[derive(Clone, Copy, Debug)]
pub struct Segment {
ident: Ident,
id: Option<NodeId>,
}
impl Segment {
fn from_path(path: &Path) -> Vec<Segment> {
path.segments.iter().map(|s| s.into()).collect()
}
fn from_ident(ident: Ident) -> Segment {
Segment {
ident,
id: None,
}
}
fn names_to_string(segments: &[Segment]) -> String {
names_to_string(&segments.iter()
.map(|seg| seg.ident.name)
.collect::<Vec<_>>())
}
}
impl<'a> From<&'a ast::PathSegment> for Segment {
fn from(seg: &'a ast::PathSegment) -> Segment {
Segment {
ident: seg.ident,
id: Some(seg.id),
}
}
}
struct UsePlacementFinder {
target_module: NodeId,
span: Option<Span>,
found_use: bool,
}
impl UsePlacementFinder {
fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
let mut finder = UsePlacementFinder {
target_module,
span: None,
found_use: false,
};
visit::walk_crate(&mut finder, krate);
(finder.span, finder.found_use)
}
}
impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
fn visit_mod(
&mut self,
module: &'tcx ast::Mod,
_: Span,
_: &[ast::Attribute],
node_id: NodeId,
) {
if self.span.is_some() {
return;
}
if node_id != self.target_module {
visit::walk_mod(self, module);
return;
}
// find a use statement
for item in &module.items {
match item.node {
ItemKind::Use(..) => {
// don't suggest placing a use before the prelude
// import or other generated ones
if !item.span.from_expansion() {
self.span = Some(item.span.shrink_to_lo());
self.found_use = true;
return;
}
},
// don't place use before extern crate
ItemKind::ExternCrate(_) => {}
// but place them before the first other item
_ => if self.span.map_or(true, |span| item.span < span ) {
if !item.span.from_expansion() {
// don't insert between attributes and an item
if item.attrs.is_empty() {
self.span = Some(item.span.shrink_to_lo());
} else {
// find the first attribute on the item
for attr in &item.attrs {
if self.span.map_or(true, |span| attr.span < span) {
self.span = Some(attr.span.shrink_to_lo());
}
}
}
}
},
}
}
}
}
/// An intermediate resolution result.
///
/// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
/// items are visible in their whole block, while `Res`es only from the place they are defined
/// forward.
#[derive(Debug)]
enum LexicalScopeBinding<'a> {
Item(&'a NameBinding<'a>),
Res(Res),
}
impl<'a> LexicalScopeBinding<'a> {
fn item(self) -> Option<&'a NameBinding<'a>> {
match self {
LexicalScopeBinding::Item(binding) => Some(binding),
_ => None,
}
}
fn res(self) -> Res {
match self {
LexicalScopeBinding::Item(binding) => binding.res(),
LexicalScopeBinding::Res(res) => res,
}
}
}
#[derive(Copy, Clone, Debug)]
enum ModuleOrUniformRoot<'a> {
/// Regular module.
Module(Module<'a>),
/// Virtual module that denotes resolution in crate root with fallback to extern prelude.
CrateRootAndExternPrelude,
/// Virtual module that denotes resolution in extern prelude.
/// Used for paths starting with `::` on 2018 edition.
ExternPrelude,
/// Virtual module that denotes resolution in current scope.
/// Used only for resolving single-segment imports. The reason it exists is that import paths
/// are always split into two parts, the first of which should be some kind of module.
CurrentScope,
}
impl ModuleOrUniformRoot<'_> {
fn same_def(lhs: Self, rhs: Self) -> bool {
match (lhs, rhs) {
(ModuleOrUniformRoot::Module(lhs),
ModuleOrUniformRoot::Module(rhs)) => lhs.def_id() == rhs.def_id(),
(ModuleOrUniformRoot::CrateRootAndExternPrelude,
ModuleOrUniformRoot::CrateRootAndExternPrelude) |
(ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
(ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
_ => false,
}
}
}
#[derive(Clone, Debug)]
enum PathResult<'a> {
Module(ModuleOrUniformRoot<'a>),
NonModule(PartialRes),
Indeterminate,
Failed {
span: Span,
label: String,
suggestion: Option<Suggestion>,
is_error_from_last_segment: bool,
},
}
enum ModuleKind {
/// An anonymous module; e.g., just a block.
///
/// ```
/// fn main() {
/// fn f() {} // (1)
/// { // This is an anonymous module
/// f(); // This resolves to (2) as we are inside the block.
/// fn f() {} // (2)
/// }
/// f(); // Resolves to (1)
/// }
/// ```
Block(NodeId),
/// Any module with a name.
///
/// This could be:
///
/// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
/// * A trait or an enum (it implicitly contains associated types, methods and variant
/// constructors).
Def(DefKind, DefId, Name),
}
impl ModuleKind {
/// Get name of the module.
pub fn name(&self) -> Option<Name> {
match self {
ModuleKind::Block(..) => None,
ModuleKind::Def(.., name) => Some(*name),
}
}
}
type Resolutions<'a> = RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>;
/// One node in the tree of modules.
pub struct ModuleData<'a> {
parent: Option<Module<'a>>,
kind: ModuleKind,
// The def id of the closest normal module (`mod`) ancestor (including this module).
normal_ancestor_id: DefId,
// Mapping between names and their (possibly in-progress) resolutions in this module.
// Resolutions in modules from other crates are not populated until accessed.
lazy_resolutions: Resolutions<'a>,
// True if this is a module from other crate that needs to be populated on access.
populate_on_access: Cell<bool>,
// Macro invocations that can expand into items in this module.
unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
no_implicit_prelude: bool,
glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
globs: RefCell<Vec<&'a ImportDirective<'a>>>,
// Used to memoize the traits in this module for faster searches through all traits in scope.
traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
/// Span of the module itself. Used for error reporting.
span: Span,
expansion: ExpnId,
}
type Module<'a> = &'a ModuleData<'a>;
impl<'a> ModuleData<'a> {
fn new(parent: Option<Module<'a>>,
kind: ModuleKind,
normal_ancestor_id: DefId,
expansion: ExpnId,
span: Span) -> Self {
ModuleData {
parent,
kind,
normal_ancestor_id,
lazy_resolutions: Default::default(),
populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
unexpanded_invocations: Default::default(),
no_implicit_prelude: false,
glob_importers: RefCell::new(Vec::new()),
globs: RefCell::new(Vec::new()),
traits: RefCell::new(None),
span,
expansion,
}
}
fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
where R: AsMut<Resolver<'a>>, F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>)
{
for (&(ident, ns), name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
name_resolution.borrow().binding.map(|binding| f(resolver, ident, ns, binding));
}
}
fn for_each_child_stable<R, F>(&'a self, resolver: &mut R, mut f: F)
where R: AsMut<Resolver<'a>>, F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>)
{
let resolutions = resolver.as_mut().resolutions(self).borrow();
let mut resolutions = resolutions.iter().collect::<Vec<_>>();
resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
for &(&(ident, ns), &resolution) in resolutions.iter() {
resolution.borrow().binding.map(|binding| f(resolver, ident, ns, binding));
}
}
fn res(&self) -> Option<Res> {
match self.kind {
ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
_ => None,
}
}
fn def_id(&self) -> Option<DefId> {
match self.kind {
ModuleKind::Def(_, def_id, _) => Some(def_id),
_ => None,
}
}
// `self` resolves to the first module ancestor that `is_normal`.
fn is_normal(&self) -> bool {
match self.kind {
ModuleKind::Def(DefKind::Mod, _, _) => true,
_ => false,
}
}
fn is_trait(&self) -> bool {
match self.kind {
ModuleKind::Def(DefKind::Trait, _, _) => true,
_ => false,
}
}
fn nearest_item_scope(&'a self) -> Module<'a> {
match self.kind {
ModuleKind::Def(DefKind::Enum, ..) | ModuleKind::Def(DefKind::Trait, ..) =>
self.parent.expect("enum or trait module without a parent"),
_ => self,
}
}
fn is_ancestor_of(&self, mut other: &Self) -> bool {
while !ptr::eq(self, other) {
if let Some(parent) = other.parent {
other = parent;
} else {
return false;
}
}
true
}
}
impl<'a> fmt::Debug for ModuleData<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{:?}", self.res())
}
}
/// Records a possibly-private value, type, or module definition.
#[derive(Clone, Debug)]
pub struct NameBinding<'a> {
kind: NameBindingKind<'a>,
ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
expansion: ExpnId,
span: Span,
vis: ty::Visibility,
}
pub trait ToNameBinding<'a> {
fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
}
impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
self
}
}
#[derive(Clone, Debug)]
enum NameBindingKind<'a> {
Res(Res, /* is_macro_export */ bool),
Module(Module<'a>),
Import {
binding: &'a NameBinding<'a>,
directive: &'a ImportDirective<'a>,
used: Cell<bool>,
},
}
impl<'a> NameBindingKind<'a> {
/// Is this a name binding of a import?
fn is_import(&self) -> bool {
match *self {
NameBindingKind::Import { .. } => true,
_ => false,
}
}
}
struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
struct UseError<'a> {
err: DiagnosticBuilder<'a>,
/// Attach `use` statements for these candidates.
candidates: Vec<ImportSuggestion>,
/// The `NodeId` of the module to place the use-statements in.
node_id: NodeId,
/// Whether the diagnostic should state that it's "better".
better: bool,
}
#[derive(Clone, Copy, PartialEq, Debug)]
enum AmbiguityKind {
Import,
BuiltinAttr,
DeriveHelper,
LegacyHelperVsPrelude,
LegacyVsModern,
GlobVsOuter,
GlobVsGlob,
GlobVsExpanded,
MoreExpandedVsOuter,
}
impl AmbiguityKind {
fn descr(self) -> &'static str {
match self {
AmbiguityKind::Import =>
"name vs any other name during import resolution",
AmbiguityKind::BuiltinAttr =>
"built-in attribute vs any other name",
AmbiguityKind::DeriveHelper =>
"derive helper attribute vs any other name",
AmbiguityKind::LegacyHelperVsPrelude =>
"legacy plugin helper attribute vs name from prelude",
AmbiguityKind::LegacyVsModern =>
"`macro_rules` vs non-`macro_rules` from other module",
AmbiguityKind::GlobVsOuter =>
"glob import vs any other name from outer scope during import/macro resolution",
AmbiguityKind::GlobVsGlob =>
"glob import vs glob import in the same module",
AmbiguityKind::GlobVsExpanded =>
"glob import vs macro-expanded name in the same \
module during import/macro resolution",
AmbiguityKind::MoreExpandedVsOuter =>
"macro-expanded name vs less macro-expanded name \
from outer scope during import/macro resolution",
}
}
}
/// Miscellaneous bits of metadata for better ambiguity error reporting.
#[derive(Clone, Copy, PartialEq)]
enum AmbiguityErrorMisc {
SuggestCrate,
SuggestSelf,
FromPrelude,
None,
}
struct AmbiguityError<'a> {
kind: AmbiguityKind,
ident: Ident,
b1: &'a NameBinding<'a>,
b2: &'a NameBinding<'a>,
misc1: AmbiguityErrorMisc,
misc2: AmbiguityErrorMisc,
}
impl<'a> NameBinding<'a> {
fn module(&self) -> Option<Module<'a>> {
match self.kind {
NameBindingKind::Module(module) => Some(module),
NameBindingKind::Import { binding, .. } => binding.module(),
_ => None,
}
}
fn res(&self) -> Res {
match self.kind {
NameBindingKind::Res(res, _) => res,
NameBindingKind::Module(module) => module.res().unwrap(),
NameBindingKind::Import { binding, .. } => binding.res(),
}
}
fn is_ambiguity(&self) -> bool {
self.ambiguity.is_some() || match self.kind {
NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
_ => false,
}
}
// We sometimes need to treat variants as `pub` for backwards compatibility.
fn pseudo_vis(&self) -> ty::Visibility {
if self.is_variant() && self.res().def_id().is_local() {
ty::Visibility::Public
} else {
self.vis
}
}
fn is_variant(&self) -> bool {
match self.kind {
NameBindingKind::Res(Res::Def(DefKind::Variant, _), _) |
NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
_ => false,
}
}
fn is_extern_crate(&self) -> bool {
match self.kind {
NameBindingKind::Import {
directive: &ImportDirective {
subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
}, ..
} => true,
NameBindingKind::Module(
&ModuleData { kind: ModuleKind::Def(DefKind::Mod, def_id, _), .. }
) => def_id.index == CRATE_DEF_INDEX,
_ => false,
}
}
fn is_import(&self) -> bool {
match self.kind {
NameBindingKind::Import { .. } => true,
_ => false,
}
}
fn is_glob_import(&self) -> bool {
match self.kind {
NameBindingKind::Import { directive, .. } => directive.is_glob(),
_ => false,
}
}
fn is_importable(&self) -> bool {
match self.res() {
Res::Def(DefKind::AssocConst, _)
| Res::Def(DefKind::Method, _)
| Res::Def(DefKind::AssocTy, _) => false,
_ => true,
}
}
fn is_macro_def(&self) -> bool {
match self.kind {
NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
_ => false,
}
}
fn macro_kind(&self) -> Option<MacroKind> {
self.res().macro_kind()
}
// Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
// at some expansion round `max(invoc, binding)` when they both emerged from macros.
// Then this function returns `true` if `self` may emerge from a macro *after* that
// in some later round and screw up our previously found resolution.
// See more detailed explanation in
// https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
// self > max(invoc, binding) => !(self <= invoc || self <= binding)
// Expansions are partially ordered, so "may appear after" is an inversion of
// "certainly appears before or simultaneously" and includes unordered cases.
let self_parent_expansion = self.expansion;
let other_parent_expansion = binding.expansion;
let certainly_before_other_or_simultaneously =
other_parent_expansion.is_descendant_of(self_parent_expansion);
let certainly_before_invoc_or_simultaneously =
invoc_parent_expansion.is_descendant_of(self_parent_expansion);
!(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
}
}
/// Interns the names of the primitive types.
///
/// All other types are defined somewhere and possibly imported, but the primitive ones need
/// special handling, since they have no place of origin.
struct PrimitiveTypeTable {
primitive_types: FxHashMap<Name, PrimTy>,
}
impl PrimitiveTypeTable {
fn new() -> PrimitiveTypeTable {
let mut table = FxHashMap::default();
table.insert(sym::bool, Bool);
table.insert(sym::char, Char);
table.insert(sym::f32, Float(FloatTy::F32));
table.insert(sym::f64, Float(FloatTy::F64));
table.insert(sym::isize, Int(IntTy::Isize));
table.insert(sym::i8, Int(IntTy::I8));
table.insert(sym::i16, Int(IntTy::I16));
table.insert(sym::i32, Int(IntTy::I32));
table.insert(sym::i64, Int(IntTy::I64));
table.insert(sym::i128, Int(IntTy::I128));
table.insert(sym::str, Str);
table.insert(sym::usize, Uint(UintTy::Usize));
table.insert(sym::u8, Uint(UintTy::U8));
table.insert(sym::u16, Uint(UintTy::U16));
table.insert(sym::u32, Uint(UintTy::U32));
table.insert(sym::u64, Uint(UintTy::U64));
table.insert(sym::u128, Uint(UintTy::U128));
Self { primitive_types: table }
}
}
#[derive(Debug, Default, Clone)]
pub struct ExternPreludeEntry<'a> {
extern_crate_item: Option<&'a NameBinding<'a>>,
pub introduced_by_item: bool,
}
/// The main resolver class.
///
/// This is the visitor that walks the whole crate.
pub struct Resolver<'a> {
session: &'a Session,
cstore: &'a CStore,
pub definitions: Definitions,
pub graph_root: Module<'a>,
prelude: Option<Module<'a>>,
pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
/// N.B., this is used only for better diagnostics, not name resolution itself.
has_self: FxHashSet<DefId>,
/// Names of fields of an item `DefId` accessible with dot syntax.
/// Used for hints during error reporting.
field_names: FxHashMap<DefId, Vec<Name>>,
/// All imports known to succeed or fail.
determined_imports: Vec<&'a ImportDirective<'a>>,
/// All non-determined imports.
indeterminate_imports: Vec<&'a ImportDirective<'a>>,
/// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
/// We are resolving a last import segment during import validation.
last_import_segment: bool,
/// This binding should be ignored during in-module resolution, so that we don't get
/// "self-confirming" import resolutions during import validation.
blacklisted_binding: Option<&'a NameBinding<'a>>,
/// The idents for the primitive types.
primitive_type_table: PrimitiveTypeTable,
/// Resolutions for nodes that have a single resolution.
partial_res_map: NodeMap<PartialRes>,
/// Resolutions for import nodes, which have multiple resolutions in different namespaces.
import_res_map: NodeMap<PerNS<Option<Res>>>,
/// Resolutions for labels (node IDs of their corresponding blocks or loops).
label_res_map: NodeMap<NodeId>,
pub export_map: ExportMap<NodeId>,
pub trait_map: TraitMap,
/// A map from nodes to anonymous modules.
/// Anonymous modules are pseudo-modules that are implicitly created around items
/// contained within blocks.
///
/// For example, if we have this:
///
/// fn f() {
/// fn g() {
/// ...
/// }
/// }
///
/// There will be an anonymous module created around `g` with the ID of the
/// entry block for `f`.
block_map: NodeMap<Module<'a>>,
/// A fake module that contains no definition and no prelude. Used so that
/// some AST passes can generate identifiers that only resolve to local or
/// language items.
empty_module: Module<'a>,
module_map: FxHashMap<DefId, Module<'a>>,
extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
/// Maps glob imports to the names of items actually imported.
pub glob_map: GlobMap,
used_imports: FxHashSet<(NodeId, Namespace)>,
pub maybe_unused_trait_imports: NodeSet,
pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
/// Privacy errors are delayed until the end in order to deduplicate them.
privacy_errors: Vec<PrivacyError<'a>>,
/// Ambiguity errors are delayed for deduplication.
ambiguity_errors: Vec<AmbiguityError<'a>>,
/// `use` injections are delayed for better placement and deduplication.
use_injections: Vec<UseError<'a>>,
/// Crate-local macro expanded `macro_export` referred to by a module-relative path.
macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
arenas: &'a ResolverArenas<'a>,
dummy_binding: &'a NameBinding<'a>,
crate_loader: &'a mut CrateLoader<'a>,
macro_names: FxHashSet<Ident>,
builtin_macros: FxHashMap<Name, SyntaxExtension>,
macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
pub all_macros: FxHashMap<Name, Res>,
macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
dummy_ext_bang: Lrc<SyntaxExtension>,
dummy_ext_derive: Lrc<SyntaxExtension>,
non_macro_attrs: [Lrc<SyntaxExtension>; 2],
macro_defs: FxHashMap<ExpnId, DefId>,
local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
unused_macros: NodeMap<Span>,
proc_macro_stubs: NodeSet,
/// Traces collected during macro resolution and validated when it's complete.
single_segment_macro_resolutions: Vec<(Ident, MacroKind, ParentScope<'a>,
Option<&'a NameBinding<'a>>)>,
multi_segment_macro_resolutions: Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
Option<Res>)>,
builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
/// Some built-in derives mark items they are applied to so they are treated specially later.
/// Derive macros cannot modify the item themselves and have to store the markers in the global
/// context, so they attach the markers to derive container IDs using this resolver table.
/// FIXME: Find a way for `PartialEq` and `Eq` to emulate `#[structural_match]`
/// by marking the produced impls rather than the original items.
special_derives: FxHashMap<ExpnId, SpecialDerives>,
/// Parent scopes in which the macros were invoked.
/// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
/// Legacy scopes *produced* by expanding the macro invocations,
/// include all the `macro_rules` items and other invocations generated by them.
output_legacy_scopes: FxHashMap<ExpnId, LegacyScope<'a>>,
/// Avoid duplicated errors for "name already defined".
name_already_seen: FxHashMap<Name, Span>,
potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
/// Table for mapping struct IDs into struct constructor IDs,
/// it's not used during normal resolution, only for better error reporting.
struct_constructors: DefIdMap<(Res, ty::Visibility)>,
/// Features enabled for this crate.
active_features: FxHashSet<Name>,
/// Stores enum visibilities to properly build a reduced graph
/// when visiting the correspondent variants.
variant_vis: DefIdMap<ty::Visibility>,
}
/// Nothing really interesting here; it just provides memory for the rest of the crate.
#[derive(Default)]
pub struct ResolverArenas<'a> {
modules: arena::TypedArena<ModuleData<'a>>,
local_modules: RefCell<Vec<Module<'a>>>,
name_bindings: arena::TypedArena<NameBinding<'a>>,
import_directives: arena::TypedArena<ImportDirective<'a>>,
name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
ast_paths: arena::TypedArena<ast::Path>,
}
impl<'a> ResolverArenas<'a> {
fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
let module = self.modules.alloc(module);
if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
self.local_modules.borrow_mut().push(module);
}
module
}
fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
self.local_modules.borrow()
}
fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
self.name_bindings.alloc(name_binding)
}
fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
-> &'a ImportDirective<'_> {
self.import_directives.alloc(import_directive)
}
fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
self.name_resolutions.alloc(Default::default())
}
fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
self.legacy_bindings.alloc(binding)
}
fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
self.ast_paths.alloc_from_iter(paths.iter().cloned())
}
}
impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
fn as_mut(&mut self) -> &mut Resolver<'a> { self }
}
impl<'a, 'b> ty::DefIdTree for &'a Resolver<'b> {
fn parent(self, id: DefId) -> Option<DefId> {
match id.krate {
LOCAL_CRATE => self.definitions.def_key(id.index).parent,
_ => self.cstore.def_key(id).parent,
}.map(|index| DefId { index, ..id })
}
}
/// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
/// the resolver is no longer needed as all the relevant information is inline.
impl<'a> hir::lowering::Resolver for Resolver<'a> {
fn resolve_str_path(
&mut self,
span: Span,
crate_root: Option<Name>,
components: &[Name],
ns: Namespace,
) -> (ast::Path, Res) {
let root = if crate_root.is_some() {
kw::PathRoot
} else {
kw::Crate
};
let segments = iter::once(Ident::with_dummy_span(root))
.chain(
crate_root.into_iter()
.chain(components.iter().cloned())
.map(Ident::with_dummy_span)
).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
let path = ast::Path {
span,
segments,
};
let parent_scope = &ParentScope::module(self.graph_root);
let res = match self.resolve_ast_path(&path, ns, parent_scope) {
Ok(res) => res,
Err((span, error)) => {
self.report_error(span, error);
Res::Err
}
};
(path, res)
}
fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
self.partial_res_map.get(&id).cloned()
}
fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
self.import_res_map.get(&id).cloned().unwrap_or_default()
}
fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
self.label_res_map.get(&id).cloned()
}
fn definitions(&mut self) -> &mut Definitions {
&mut self.definitions
}
fn has_derives(&self, node_id: NodeId, derives: SpecialDerives) -> bool {
let def_id = self.definitions.local_def_id(node_id);
let expn_id = self.definitions.expansion_that_defined(def_id.index);
self.has_derives(expn_id, derives)
}
}
impl<'a> Resolver<'a> {
pub fn new(session: &'a Session,
cstore: &'a CStore,
krate: &Crate,
crate_name: &str,
crate_loader: &'a mut CrateLoader<'a>,
arenas: &'a ResolverArenas<'a>)
-> Resolver<'a> {
let root_def_id = DefId::local(CRATE_DEF_INDEX);
let root_module_kind = ModuleKind::Def(
DefKind::Mod,
root_def_id,
kw::Invalid,
);
let graph_root = arenas.alloc_module(ModuleData {
no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
});
let empty_module_kind = ModuleKind::Def(
DefKind::Mod,
root_def_id,
kw::Invalid,
);
let empty_module = arenas.alloc_module(ModuleData {
no_implicit_prelude: true,
..ModuleData::new(
Some(graph_root),
empty_module_kind,
root_def_id,
ExpnId::root(),
DUMMY_SP,
)
});
let mut module_map = FxHashMap::default();
module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
let mut definitions = Definitions::default();
definitions.create_root_def(crate_name, session.local_crate_disambiguator());
let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
.collect();
if !attr::contains_name(&krate.attrs, sym::no_core) {
extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
if !attr::contains_name(&krate.attrs, sym::no_std) {
extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
if session.rust_2018() {
extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
}
}
}
let mut invocation_parent_scopes = FxHashMap::default();
invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
let mut macro_defs = FxHashMap::default();
macro_defs.insert(ExpnId::root(), root_def_id);
let features = session.features_untracked();
let non_macro_attr =
|mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
Resolver {
session,
cstore,
definitions,
// The outermost module has def ID 0; this is not reflected in the
// AST.
graph_root,
prelude: None,
extern_prelude,
has_self: FxHashSet::default(),
field_names: FxHashMap::default(),
determined_imports: Vec::new(),
indeterminate_imports: Vec::new(),
last_import_segment: false,
blacklisted_binding: None,
primitive_type_table: PrimitiveTypeTable::new(),
partial_res_map: Default::default(),
import_res_map: Default::default(),
label_res_map: Default::default(),
export_map: FxHashMap::default(),
trait_map: Default::default(),
empty_module,
module_map,
block_map: Default::default(),
extern_module_map: FxHashMap::default(),
binding_parent_modules: FxHashMap::default(),
ast_transform_scopes: FxHashMap::default(),
glob_map: Default::default(),
used_imports: FxHashSet::default(),
maybe_unused_trait_imports: Default::default(),
maybe_unused_extern_crates: Vec::new(),
privacy_errors: Vec::new(),
ambiguity_errors: Vec::new(),
use_injections: Vec::new(),
macro_expanded_macro_export_errors: BTreeSet::new(),
arenas,
dummy_binding: arenas.alloc_name_binding(NameBinding {
kind: NameBindingKind::Res(Res::Err, false),
ambiguity: None,
expansion: ExpnId::root(),
span: DUMMY_SP,
vis: ty::Visibility::Public,
}),
crate_loader,
macro_names: FxHashSet::default(),
builtin_macros: Default::default(),
macro_use_prelude: FxHashMap::default(),
all_macros: FxHashMap::default(),
macro_map: FxHashMap::default(),
dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
invocation_parent_scopes,
output_legacy_scopes: Default::default(),
macro_defs,
local_macro_def_scopes: FxHashMap::default(),
name_already_seen: FxHashMap::default(),
potentially_unused_imports: Vec::new(),
struct_constructors: Default::default(),
unused_macros: Default::default(),
proc_macro_stubs: Default::default(),
single_segment_macro_resolutions: Default::default(),
multi_segment_macro_resolutions: Default::default(),
builtin_attrs: Default::default(),
special_derives: Default::default(),
active_features:
features.declared_lib_features.iter().map(|(feat, ..)| *feat)
.chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
.collect(),
variant_vis: Default::default()
}
}
pub fn arenas() -> ResolverArenas<'a> {
Default::default()
}
fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
self.non_macro_attrs[mark_used as usize].clone()
}
fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
match macro_kind {
MacroKind::Bang => self.dummy_ext_bang.clone(),
MacroKind::Derive => self.dummy_ext_derive.clone(),
MacroKind::Attr => self.non_macro_attr(true),
}
}
/// Runs the function on each namespace.
fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
f(self, TypeNS);
f(self, ValueNS);
f(self, MacroNS);
}
fn is_builtin_macro(&mut self, res: Res) -> bool {
self.get_macro(res).map_or(false, |ext| ext.is_builtin)
}
fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
loop {
match self.macro_defs.get(&ctxt.outer_expn()) {
Some(&def_id) => return def_id,
None => ctxt.remove_mark(),
};
}
}
fn has_derives(&self, expn_id: ExpnId, markers: SpecialDerives) -> bool {
self.special_derives.get(&expn_id).map_or(false, |m| m.contains(markers))
}
/// Entry point to crate resolution.
pub fn resolve_crate(&mut self, krate: &Crate) {
ImportResolver { r: self }.finalize_imports();
self.finalize_macro_resolutions();
self.late_resolve_crate(krate);
self.check_unused(krate);
self.report_errors(krate);
self.crate_loader.postprocess(krate);
}
fn new_module(
&self,
parent: Module<'a>,
kind: ModuleKind,
normal_ancestor_id: DefId,
expn_id: ExpnId,
span: Span,
) -> Module<'a> {
let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
self.arenas.alloc_module(module)
}
fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
if module.populate_on_access.get() {
module.populate_on_access.set(false);
self.build_reduced_graph_external(module);
}
&module.lazy_resolutions
}
fn resolution(&mut self, module: Module<'a>, ident: Ident, ns: Namespace)
-> &'a RefCell<NameResolution<'a>> {
*self.resolutions(module).borrow_mut().entry((ident.modern(), ns))
.or_insert_with(|| self.arenas.alloc_name_resolution())
}
fn record_use(&mut self, ident: Ident, ns: Namespace,
used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
if let Some((b2, kind)) = used_binding.ambiguity {
self.ambiguity_errors.push(AmbiguityError {
kind, ident, b1: used_binding, b2,
misc1: AmbiguityErrorMisc::None,
misc2: AmbiguityErrorMisc::None,
});
}
if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
// Avoid marking `extern crate` items that refer to a name from extern prelude,
// but not introduce it, as used if they are accessed from lexical scope.
if is_lexical_scope {
if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
if let Some(crate_item) = entry.extern_crate_item {
if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
return;
}
}
}
}
used.set(true);
directive.used.set(true);
self.used_imports.insert((directive.id, ns));
self.add_to_glob_map(&directive, ident);
self.record_use(ident, ns, binding, false);
}
}
#[inline]
fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
if directive.is_glob() {
self.glob_map.entry(directive.id).or_default().insert(ident.name);
}
}
/// A generic scope visitor.
/// Visits scopes in order to resolve some identifier in them or perform other actions.
/// If the callback returns `Some` result, we stop visiting scopes and return it.
fn visit_scopes<T>(
&mut self,
scope_set: ScopeSet,
parent_scope: &ParentScope<'a>,
ident: Ident,
mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
) -> Option<T> {
// General principles:
// 1. Not controlled (user-defined) names should have higher priority than controlled names
// built into the language or standard library. This way we can add new names into the
// language or standard library without breaking user code.
// 2. "Closed set" below means new names cannot appear after the current resolution attempt.
// Places to search (in order of decreasing priority):
// (Type NS)
// 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
// (open set, not controlled).
// 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
// (open, not controlled).
// 3. Extern prelude (open, the open part is from macro expansions, not controlled).
// 4. Tool modules (closed, controlled right now, but not in the future).
// 5. Standard library prelude (de-facto closed, controlled).
// 6. Language prelude (closed, controlled).
// (Value NS)
// 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
// (open set, not controlled).
// 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
// (open, not controlled).
// 3. Standard library prelude (de-facto closed, controlled).
// (Macro NS)
// 1-3. Derive helpers (open, not controlled). All ambiguities with other names
// are currently reported as errors. They should be higher in priority than preludes
// and probably even names in modules according to the "general principles" above. They
// also should be subject to restricted shadowing because are effectively produced by
// derives (you need to resolve the derive first to add helpers into scope), but they
// should be available before the derive is expanded for compatibility.
// It's mess in general, so we are being conservative for now.
// 1-3. `macro_rules` (open, not controlled), loop through legacy scopes. Have higher
// priority than prelude macros, but create ambiguities with macros in modules.
// 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
// (open, not controlled). Have higher priority than prelude macros, but create
// ambiguities with `macro_rules`.
// 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
// 4a. User-defined prelude from macro-use
// (open, the open part is from macro expansions, not controlled).
// 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
// 4c. Standard library prelude (de-facto closed, controlled).
// 6. Language prelude: builtin attributes (closed, controlled).
// 4-6. Legacy plugin helpers (open, not controlled). Similar to derive helpers,
// but introduced by legacy plugins using `register_attribute`. Priority is somewhere
// in prelude, not sure where exactly (creates ambiguities with any other prelude names).
let rust_2015 = ident.span.rust_2015();
let (ns, is_absolute_path) = match scope_set {
ScopeSet::All(ns, _) => (ns, false),
ScopeSet::AbsolutePath(ns) => (ns, true),
ScopeSet::Macro(_) => (MacroNS, false),
};
// Jump out of trait or enum modules, they do not act as scopes.
let module = parent_scope.module.nearest_item_scope();
let mut scope = match ns {
_ if is_absolute_path => Scope::CrateRoot,
TypeNS | ValueNS => Scope::Module(module),
MacroNS => Scope::DeriveHelpers,
};
let mut ident = ident.modern();
let mut use_prelude = !module.no_implicit_prelude;
loop {
let visit = match scope {
Scope::DeriveHelpers => true,
Scope::MacroRules(..) => true,
Scope::CrateRoot => true,
Scope::Module(..) => true,
Scope::MacroUsePrelude => use_prelude || rust_2015,
Scope::BuiltinAttrs => true,
Scope::LegacyPluginHelpers => use_prelude || rust_2015,
Scope::ExternPrelude => use_prelude || is_absolute_path,
Scope::ToolPrelude => use_prelude,
Scope::StdLibPrelude => use_prelude || ns == MacroNS,
Scope::BuiltinTypes => true,
};
if visit {
if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
return break_result;
}
}
scope = match scope {
Scope::DeriveHelpers =>
Scope::MacroRules(parent_scope.legacy),
Scope::MacroRules(legacy_scope) => match legacy_scope {
LegacyScope::Binding(binding) => Scope::MacroRules(
binding.parent_legacy_scope
),
LegacyScope::Invocation(invoc_id) => Scope::MacroRules(
self.output_legacy_scopes.get(&invoc_id).cloned()
.unwrap_or(self.invocation_parent_scopes[&invoc_id].legacy)
),
LegacyScope::Empty => Scope::Module(module),
}
Scope::CrateRoot => match ns {
TypeNS => {
ident.span.adjust(ExpnId::root());
Scope::ExternPrelude
}
ValueNS | MacroNS => break,
}
Scope::Module(module) => {
use_prelude = !module.no_implicit_prelude;
match self.hygienic_lexical_parent(module, &mut ident.span) {
Some(parent_module) => Scope::Module(parent_module),
None => {
ident.span.adjust(ExpnId::root());
match ns {
TypeNS => Scope::ExternPrelude,
ValueNS => Scope::StdLibPrelude,
MacroNS => Scope::MacroUsePrelude,
}
}
}
}
Scope::MacroUsePrelude => Scope::StdLibPrelude,
Scope::BuiltinAttrs => Scope::LegacyPluginHelpers,
Scope::LegacyPluginHelpers => break, // nowhere else to search
Scope::ExternPrelude if is_absolute_path => break,
Scope::ExternPrelude => Scope::ToolPrelude,
Scope::ToolPrelude => Scope::StdLibPrelude,
Scope::StdLibPrelude => match ns {
TypeNS => Scope::BuiltinTypes,
ValueNS => break, // nowhere else to search
MacroNS => Scope::BuiltinAttrs,
}
Scope::BuiltinTypes => break, // nowhere else to search
};
}
None
}
/// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
/// More specifically, we proceed up the hierarchy of scopes and return the binding for
/// `ident` in the first scope that defines it (or None if no scopes define it).
///
/// A block's items are above its local variables in the scope hierarchy, regardless of where
/// the items are defined in the block. For example,
/// ```rust
/// fn f() {
/// g(); // Since there are no local variables in scope yet, this resolves to the item.
/// let g = || {};
/// fn g() {}
/// g(); // This resolves to the local variable `g` since it shadows the item.
/// }
/// ```
///
/// Invariant: This must only be called during main resolution, not during
/// import resolution.
fn resolve_ident_in_lexical_scope(&mut self,
mut ident: Ident,
ns: Namespace,
parent_scope: &ParentScope<'a>,
record_used_id: Option<NodeId>,
path_span: Span,
ribs: &[Rib<'a>])
-> Option<LexicalScopeBinding<'a>> {
assert!(ns == TypeNS || ns == ValueNS);
if ident.name == kw::Invalid {
return Some(LexicalScopeBinding::Res(Res::Err));
}
let (general_span, modern_span) = if ident.name == kw::SelfUpper {
// FIXME(jseyfried) improve `Self` hygiene
let empty_span = ident.span.with_ctxt(SyntaxContext::root());
(empty_span, empty_span)
} else if ns == TypeNS {
let modern_span = ident.span.modern();
(modern_span, modern_span)
} else {
(ident.span.modern_and_legacy(), ident.span.modern())
};
ident.span = general_span;
let modern_ident = Ident { span: modern_span, ..ident };
// Walk backwards up the ribs in scope.
let record_used = record_used_id.is_some();
let mut module = self.graph_root;
for i in (0 .. ribs.len()).rev() {
debug!("walk rib\n{:?}", ribs[i].bindings);
// Use the rib kind to determine whether we are resolving parameters
// (modern hygiene) or local variables (legacy hygiene).
let rib_ident = if ribs[i].kind.contains_params() {
modern_ident
} else {
ident
};
if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
// The ident resolves to a type parameter or local variable.
return Some(LexicalScopeBinding::Res(
self.validate_res_from_ribs(i, res, record_used, path_span, ribs),
));
}
module = match ribs[i].kind {
ModuleRibKind(module) => module,
MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
// If an invocation of this macro created `ident`, give up on `ident`
// and switch to `ident`'s source from the macro definition.
ident.span.remove_mark();
continue
}
_ => continue,
};
let item = self.resolve_ident_in_module_unadjusted(
ModuleOrUniformRoot::Module(module),
ident,
ns,
parent_scope,
record_used,
path_span,
);
if let Ok(binding) = item {
// The ident resolves to an item.
return Some(LexicalScopeBinding::Item(binding));
}
match module.kind {
ModuleKind::Block(..) => {}, // We can see through blocks
_ => break,
}
}
ident = modern_ident;
let mut poisoned = None;
loop {
let opt_module = if let Some(node_id) = record_used_id {
self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
node_id, &mut poisoned)
} else {
self.hygienic_lexical_parent(module, &mut ident.span)
};
module = unwrap_or!(opt_module, break);
let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
let result = self.resolve_ident_in_module_unadjusted(
ModuleOrUniformRoot::Module(module),
ident,
ns,
adjusted_parent_scope,
record_used,
path_span,
);
match result {
Ok(binding) => {
if let Some(node_id) = poisoned {
self.session.buffer_lint_with_diagnostic(
lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
node_id, ident.span,
&format!("cannot find {} `{}` in this scope", ns.descr(), ident),
lint::builtin::BuiltinLintDiagnostics::
ProcMacroDeriveResolutionFallback(ident.span),
);
}
return Some(LexicalScopeBinding::Item(binding))
}
Err(Determined) => continue,
Err(Undetermined) =>
span_bug!(ident.span, "undetermined resolution during main resolution pass"),
}
}
if !module.no_implicit_prelude {
ident.span.adjust(ExpnId::root());
if ns == TypeNS {
if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
return Some(LexicalScopeBinding::Item(binding));
}
}
if ns == TypeNS && KNOWN_TOOLS.contains(&ident.name) {
let binding = (Res::ToolMod, ty::Visibility::Public,
DUMMY_SP, ExpnId::root()).to_name_binding(self.arenas);
return Some(LexicalScopeBinding::Item(binding));
}
if let Some(prelude) = self.prelude {
if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
ModuleOrUniformRoot::Module(prelude),
ident,
ns,
parent_scope,
false,
path_span,
) {
return Some(LexicalScopeBinding::Item(binding));
}
}
}
None
}
fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
-> Option<Module<'a>> {
if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
return Some(self.macro_def_scope(span.remove_mark()));
}
if let ModuleKind::Block(..) = module.kind {
return Some(module.parent.unwrap().nearest_item_scope());
}
None
}
fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
span: &mut Span, node_id: NodeId,
poisoned: &mut Option<NodeId>)
-> Option<Module<'a>> {
if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
return module;
}
// We need to support the next case under a deprecation warning
// ```
// struct MyStruct;
// ---- begin: this comes from a proc macro derive
// mod implementation_details {
// // Note that `MyStruct` is not in scope here.
// impl SomeTrait for MyStruct { ... }
// }
// ---- end
// ```
// So we have to fall back to the module's parent during lexical resolution in this case.
if let Some(parent) = module.parent {
// Inner module is inside the macro, parent module is outside of the macro.
if module.expansion != parent.expansion &&
module.expansion.is_descendant_of(parent.expansion) {
// The macro is a proc macro derive
if let Some(&def_id) = self.macro_defs.get(&module.expansion) {
if let Some(ext) = self.get_macro_by_def_id(def_id) {
if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
*poisoned = Some(node_id);
return module.parent;
}
}
}
}
}
}
None
}
fn resolve_ident_in_module(
&mut self,
module: ModuleOrUniformRoot<'a>,
ident: Ident,
ns: Namespace,
parent_scope: &ParentScope<'a>,
record_used: bool,
path_span: Span
) -> Result<&'a NameBinding<'a>, Determinacy> {
self.resolve_ident_in_module_ext(
module, ident, ns, parent_scope, record_used, path_span
).map_err(|(determinacy, _)| determinacy)
}
fn resolve_ident_in_module_ext(
&mut self,
module: ModuleOrUniformRoot<'a>,
mut ident: Ident,
ns: Namespace,
parent_scope: &ParentScope<'a>,
record_used: bool,
path_span: Span
) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
let tmp_parent_scope;
let mut adjusted_parent_scope = parent_scope;
match module {
ModuleOrUniformRoot::Module(m) => {
if let Some(def) = ident.span.modernize_and_adjust(m.expansion) {
tmp_parent_scope =
ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
adjusted_parent_scope = &tmp_parent_scope;
}
}
ModuleOrUniformRoot::ExternPrelude => {
ident.span.modernize_and_adjust(ExpnId::root());
}
ModuleOrUniformRoot::CrateRootAndExternPrelude |
ModuleOrUniformRoot::CurrentScope => {
// No adjustments
}
}
let result = self.resolve_ident_in_module_unadjusted_ext(
module, ident, ns, adjusted_parent_scope, false, record_used, path_span,
);
result
}
fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
let mut ctxt = ident.span.ctxt();
let mark = if ident.name == kw::DollarCrate {
// When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
// we don't want to pretend that the `macro_rules!` definition is in the `macro`
// as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
// FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
// definitions actually produced by `macro` and `macro` definitions produced by
// `macro_rules!`, but at least such configurations are not stable yet.
ctxt = ctxt.modern_and_legacy();
let mut iter = ctxt.marks().into_iter().rev().peekable();
let mut result = None;
// Find the last modern mark from the end if it exists.
while let Some(&(mark, transparency)) = iter.peek() {
if transparency == Transparency::Opaque {
result = Some(mark);
iter.next();
} else {
break;
}
}
// Then find the last legacy mark from the end if it exists.
for (mark, transparency) in iter {
if transparency == Transparency::SemiTransparent {
result = Some(mark);
} else {
break;
}
}
result
} else {
ctxt = ctxt.modern();
ctxt.adjust(ExpnId::root())
};
let module = match mark {
Some(def) => self.macro_def_scope(def),
None => return self.graph_root,
};
self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
}
fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
let mut module = self.get_module(module.normal_ancestor_id);
while module.span.ctxt().modern() != *ctxt {
let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
module = self.get_module(parent.normal_ancestor_id);
}
module
}
fn resolve_path(
&mut self,
path: &[Segment],
opt_ns: Option<Namespace>, // `None` indicates a module path in import
parent_scope: &ParentScope<'a>,
record_used: bool,
path_span: Span,
crate_lint: CrateLint,
) -> PathResult<'a> {
self.resolve_path_with_ribs(
path, opt_ns, parent_scope, record_used, path_span, crate_lint, None
)
}
fn resolve_path_with_ribs(
&mut self,
path: &[Segment],
opt_ns: Option<Namespace>, // `None` indicates a module path in import
parent_scope: &ParentScope<'a>,
record_used: bool,
path_span: Span,
crate_lint: CrateLint,
ribs: Option<&PerNS<Vec<Rib<'a>>>>,
) -> PathResult<'a> {
let mut module = None;
let mut allow_super = true;
let mut second_binding = None;
debug!(
"resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
path_span={:?}, crate_lint={:?})",
path,
opt_ns,
record_used,
path_span,
crate_lint,
);
for (i, &Segment { ident, id }) in path.iter().enumerate() {
debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
let record_segment_res = |this: &mut Self, res| {
if record_used {
if let Some(id) = id {
if !this.partial_res_map.contains_key(&id) {
assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
this.record_partial_res(id, PartialRes::new(res));
}
}
}
};
let is_last = i == path.len() - 1;
let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
let name = ident.name;
allow_super &= ns == TypeNS &&
(name == kw::SelfLower ||
name == kw::Super);
if ns == TypeNS {
if allow_super && name == kw::Super {
let mut ctxt = ident.span.ctxt().modern();
let self_module = match i {
0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
_ => match module {
Some(ModuleOrUniformRoot::Module(module)) => Some(module),
_ => None,
},
};
if let Some(self_module) = self_module {
if let Some(parent) = self_module.parent {
module = Some(ModuleOrUniformRoot::Module(
self.resolve_self(&mut ctxt, parent)));
continue;
}
}
let msg = "there are too many initial `super`s.".to_string();
return PathResult::Failed {
span: ident.span,
label: msg,
suggestion: None,
is_error_from_last_segment: false,
};
}
if i == 0 {
if name == kw::SelfLower {
let mut ctxt = ident.span.ctxt().modern();
module = Some(ModuleOrUniformRoot::Module(
self.resolve_self(&mut ctxt, parent_scope.module)));
continue;
}
if name == kw::PathRoot && ident.span.rust_2018() {
module = Some(ModuleOrUniformRoot::ExternPrelude);
continue;
}
if name == kw::PathRoot &&
ident.span.rust_2015() && self.session.rust_2018() {
// `::a::b` from 2015 macro on 2018 global edition
module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
continue;
}
if name == kw::PathRoot ||
name == kw::Crate ||
name == kw::DollarCrate {
// `::a::b`, `crate::a::b` or `$crate::a::b`
module = Some(ModuleOrUniformRoot::Module(
self.resolve_crate_root(ident)));
continue;
}
}
}
// Report special messages for path segment keywords in wrong positions.
if ident.is_path_segment_keyword() && i != 0 {
let name_str = if name == kw::PathRoot {
"crate root".to_string()
} else {
format!("`{}`", name)
};
let label = if i == 1 && path[0].ident.name == kw::PathRoot {
format!("global paths cannot start with {}", name_str)
} else {
format!("{} in paths can only be used in start position", name_str)
};
return PathResult::Failed {
span: ident.span,
label,
suggestion: None,
is_error_from_last_segment: false,
};
}
let binding = if let Some(module) = module {
self.resolve_ident_in_module(
module, ident, ns, parent_scope, record_used, path_span
)
} else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
let scopes = ScopeSet::All(ns, opt_ns.is_none());
self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
record_used, path_span)
} else {
let record_used_id =
if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
match self.resolve_ident_in_lexical_scope(
ident, ns, parent_scope, record_used_id, path_span, &ribs.unwrap()[ns]
) {
// we found a locally-imported or available item/module
Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
// we found a local variable or type param
Some(LexicalScopeBinding::Res(res))
if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
record_segment_res(self, res);
return PathResult::NonModule(PartialRes::with_unresolved_segments(
res, path.len() - 1
));
}
_ => Err(Determinacy::determined(record_used)),
}
};
match binding {
Ok(binding) => {
if i == 1 {
second_binding = Some(binding);
}
let res = binding.res();
let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
if let Some(next_module) = binding.module() {
module = Some(ModuleOrUniformRoot::Module(next_module));
record_segment_res(self, res);
} else if res == Res::ToolMod && i + 1 != path.len() {
if binding.is_import() {
self.session.struct_span_err(
ident.span, "cannot use a tool module through an import"
).span_note(
binding.span, "the tool module imported here"
).emit();
}
let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
return PathResult::NonModule(PartialRes::new(res));
} else if res == Res::Err {
return PathResult::NonModule(PartialRes::new(Res::Err));
} else if opt_ns.is_some() && (is_last || maybe_assoc) {
self.lint_if_path_starts_with_module(
crate_lint,
path,
path_span,
second_binding,
);
return PathResult::NonModule(PartialRes::with_unresolved_segments(
res, path.len() - i - 1
));
} else {
let label = format!(
"`{}` is {} {}, not a module",
ident,
res.article(),
res.descr(),
);
return PathResult::Failed {
span: ident.span,
label,
suggestion: None,
is_error_from_last_segment: is_last,
};
}
}
Err(Undetermined) => return PathResult::Indeterminate,
Err(Determined) => {
if let Some(ModuleOrUniformRoot::Module(module)) = module {
if opt_ns.is_some() && !module.is_normal() {
return PathResult::NonModule(PartialRes::with_unresolved_segments(
module.res().unwrap(), path.len() - i
));
}
}
let module_res = match module {
Some(ModuleOrUniformRoot::Module(module)) => module.res(),
_ => None,
};
let (label, suggestion) = if module_res == self.graph_root.res() {
let is_mod = |res| {
match res { Res::Def(DefKind::Mod, _) => true, _ => false }
};
let mut candidates =
self.lookup_import_candidates(ident, TypeNS, is_mod);
candidates.sort_by_cached_key(|c| {
(c.path.segments.len(), c.path.to_string())
});
if let Some(candidate) = candidates.get(0) {
(
String::from("unresolved import"),
Some((
vec![(ident.span, candidate.path.to_string())],
String::from("a similar path exists"),
Applicability::MaybeIncorrect,
)),
)
} else if !ident.is_reserved() {
(format!("maybe a missing crate `{}`?", ident), None)
} else {
// the parser will already have complained about the keyword being used
return PathResult::NonModule(PartialRes::new(Res::Err));
}
} else if i == 0 {
(format!("use of undeclared type or module `{}`", ident), None)
} else {
(format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
};
return PathResult::Failed {
span: ident.span,
label,
suggestion,
is_error_from_last_segment: is_last,
};
}
}
}
self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
PathResult::Module(match module {
Some(module) => module,
None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
_ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
})
}
fn lint_if_path_starts_with_module(
&self,
crate_lint: CrateLint,
path: &[Segment],
path_span: Span,
second_binding: Option<&NameBinding<'_>>,
) {
let (diag_id, diag_span) = match crate_lint {
CrateLint::No => return,
CrateLint::SimplePath(id) => (id, path_span),
CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
};
let first_name = match path.get(0) {
// In the 2018 edition this lint is a hard error, so nothing to do
Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
_ => return,
};
// We're only interested in `use` paths which should start with
// `{{root}}` currently.
if first_name != kw::PathRoot {
return
}
match path.get(1) {
// If this import looks like `crate::...` it's already good
Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
// Otherwise go below to see if it's an extern crate
Some(_) => {}
// If the path has length one (and it's `PathRoot` most likely)
// then we don't know whether we're gonna be importing a crate or an
// item in our crate. Defer this lint to elsewhere
None => return,
}
// If the first element of our path was actually resolved to an
// `ExternCrate` (also used for `crate::...`) then no need to issue a
// warning, this looks all good!
if let Some(binding) = second_binding {
if let NameBindingKind::Import { directive: d, .. } = binding.kind {
// Careful: we still want to rewrite paths from
// renamed extern crates.
if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
return
}
}
}
let diag = lint::builtin::BuiltinLintDiagnostics
::AbsPathWithModule(diag_span);
self.session.buffer_lint_with_diagnostic(
lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
diag_id, diag_span,
"absolute paths must start with `self`, `super`, \
`crate`, or an external crate name in the 2018 edition",
diag);
}
// Validate a local resolution (from ribs).
fn validate_res_from_ribs(
&mut self,
rib_index: usize,
res: Res,
record_used: bool,
span: Span,
all_ribs: &[Rib<'a>],
) -> Res {
debug!("validate_res_from_ribs({:?})", res);
let ribs = &all_ribs[rib_index + 1..];
// An invalid forward use of a type parameter from a previous default.
if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
if record_used {
self.report_error(span, ResolutionError::ForwardDeclaredTyParam);
}
assert_eq!(res, Res::Err);
return Res::Err;
}
// An invalid use of a type parameter as the type of a const parameter.
if let TyParamAsConstParamTy = all_ribs[rib_index].kind {
if record_used {
self.report_error(span, ResolutionError::ConstParamDependentOnTypeParam);
}
assert_eq!(res, Res::Err);
return Res::Err;
}
match res {
Res::Local(_) => {
use ResolutionError::*;
let mut res_err = None;
for rib in ribs {
match rib.kind {
NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
ForwardTyParamBanRibKind | TyParamAsConstParamTy => {
// Nothing to do. Continue.
}
ItemRibKind | FnItemRibKind | AssocItemRibKind => {
// This was an attempt to access an upvar inside a
// named function item. This is not allowed, so we
// report an error.
if record_used {
// We don't immediately trigger a resolve error, because
// we want certain other resolution errors (namely those
// emitted for `ConstantItemRibKind` below) to take
// precedence.
res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
}
}
ConstantItemRibKind => {
// Still doesn't deal with upvars
if record_used {
self.report_error(span, AttemptToUseNonConstantValueInConstant);
}
return Res::Err;
}
}
}
if let Some(res_err) = res_err {
self.report_error(span, res_err);
return Res::Err;
}
}
Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
for rib in ribs {
match rib.kind {
NormalRibKind | AssocItemRibKind |
ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
ConstantItemRibKind | TyParamAsConstParamTy => {
// Nothing to do. Continue.
}
ItemRibKind | FnItemRibKind => {
// This was an attempt to use a type parameter outside its scope.
if record_used {
self.report_error(
span, ResolutionError::GenericParamsFromOuterFunction(res)
);
}
return Res::Err;
}
}
}
}
Res::Def(DefKind::ConstParam, _) => {
let mut ribs = ribs.iter().peekable();
if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
// When declaring const parameters inside function signatures, the first rib
// is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
// (spuriously) conflicting with the const param.
ribs.next();
}
for rib in ribs {
if let ItemRibKind | FnItemRibKind = rib.kind {
// This was an attempt to use a const parameter outside its scope.
if record_used {
self.report_error(
span, ResolutionError::GenericParamsFromOuterFunction(res)
);
}
return Res::Err;
}
}
}
_ => {}
}
res
}
fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
debug!("(recording res) recording {:?} for {}", resolution, node_id);
if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
}
}
fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
vis.is_accessible_from(module.normal_ancestor_id, self)
}
fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
if !ptr::eq(module, old_module) {
span_bug!(binding.span, "parent module is reset for binding");
}
}
}
fn disambiguate_legacy_vs_modern(
&self,
legacy: &'a NameBinding<'a>,
modern: &'a NameBinding<'a>,
) -> bool {
// Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
// is disambiguated to mitigate regressions from macro modularization.
// Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
match (self.binding_parent_modules.get(&PtrKey(legacy)),
self.binding_parent_modules.get(&PtrKey(modern))) {
(Some(legacy), Some(modern)) =>
legacy.normal_ancestor_id == modern.normal_ancestor_id &&
modern.is_ancestor_of(legacy),
_ => false,
}
}
fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
let res = b.res();
if b.span.is_dummy() {
let add_built_in = match b.res() {
// These already contain the "built-in" prefix or look bad with it.
Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod => false,
_ => true,
};
let (built_in, from) = if from_prelude {
("", " from prelude")
} else if b.is_extern_crate() && !b.is_import() &&
self.session.opts.externs.get(&ident.as_str()).is_some() {
("", " passed with `--extern`")
} else if add_built_in {
(" built-in", "")
} else {
("", "")
};
let article = if built_in.is_empty() { res.article() } else { "a" };
format!("{a}{built_in} {thing}{from}",
a = article, thing = res.descr(), built_in = built_in, from = from)
} else {
let introduced = if b.is_import() { "imported" } else { "defined" };
format!("the {thing} {introduced} here",
thing = res.descr(), introduced = introduced)
}
}
fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
// We have to print the span-less alternative first, otherwise formatting looks bad.
(b2, b1, misc2, misc1, true)
} else {
(b1, b2, misc1, misc2, false)
};
let mut err = struct_span_err!(self.session, ident.span, E0659,
"`{ident}` is ambiguous ({why})",
ident = ident, why = kind.descr());
err.span_label(ident.span, "ambiguous name");
let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
let note_msg = format!("`{ident}` could{also} refer to {what}",
ident = ident, also = also, what = what);
let thing = b.res().descr();
let mut help_msgs = Vec::new();
if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
kind == AmbiguityKind::GlobVsExpanded ||
kind == AmbiguityKind::GlobVsOuter &&
swapped != also.is_empty()) {
help_msgs.push(format!("consider adding an explicit import of \
`{ident}` to disambiguate", ident = ident))
}
if b.is_extern_crate() && ident.span.rust_2018() {
help_msgs.push(format!(
"use `::{ident}` to refer to this {thing} unambiguously",
ident = ident, thing = thing,
))
}
if misc == AmbiguityErrorMisc::SuggestCrate {
help_msgs.push(format!(
"use `crate::{ident}` to refer to this {thing} unambiguously",
ident = ident, thing = thing,
))
} else if misc == AmbiguityErrorMisc::SuggestSelf {
help_msgs.push(format!(
"use `self::{ident}` to refer to this {thing} unambiguously",
ident = ident, thing = thing,
))
}
err.span_note(b.span, &note_msg);
for (i, help_msg) in help_msgs.iter().enumerate() {
let or = if i == 0 { "" } else { "or " };
err.help(&format!("{}{}", or, help_msg));
}
};
could_refer_to(b1, misc1, "");
could_refer_to(b2, misc2, " also");
err.emit();
}
fn report_errors(&mut self, krate: &Crate) {
self.report_with_use_injections(krate);
for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
let msg = "macro-expanded `macro_export` macros from the current crate \
cannot be referred to by absolute paths";
self.session.buffer_lint_with_diagnostic(
lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
CRATE_NODE_ID, span_use, msg,
lint::builtin::BuiltinLintDiagnostics::
MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
);
}
for ambiguity_error in &self.ambiguity_errors {
self.report_ambiguity_error(ambiguity_error);
}
let mut reported_spans = FxHashSet::default();
for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
if reported_spans.insert(dedup_span) {
let mut err = struct_span_err!(
self.session,
ident.span,
E0603,
"{} `{}` is private",
binding.res().descr(),
ident.name,
);
// FIXME: use the ctor's `def_id` to check wether any of the fields is not visible
match binding.kind {
NameBindingKind::Res(Res::Def(DefKind::Ctor(
CtorOf::Struct,
CtorKind::Fn,
), _def_id), _) => {
err.note("a tuple struct constructor is private if any of its fields \
is private");
}
NameBindingKind::Res(Res::Def(DefKind::Ctor(
CtorOf::Variant,
CtorKind::Fn,
), _def_id), _) => {
err.note("a tuple variant constructor is private if any of its fields \
is private");
}
_ => {}
}
err.emit();
}
}
}
fn report_with_use_injections(&mut self, krate: &Crate) {
for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
let (span, found_use) = UsePlacementFinder::check(krate, node_id);
if !candidates.is_empty() {
diagnostics::show_candidates(&mut err, span, &candidates, better, found_use);
}
err.emit();
}
}
fn report_conflict<'b>(&mut self,
parent: Module<'_>,
ident: Ident,
ns: Namespace,
new_binding: &NameBinding<'b>,
old_binding: &NameBinding<'b>) {
// Error on the second of two conflicting names
if old_binding.span.lo() > new_binding.span.lo() {
return self.report_conflict(parent, ident, ns, old_binding, new_binding);
}
let container = match parent.kind {
ModuleKind::Def(DefKind::Mod, _, _) => "module",
ModuleKind::Def(DefKind::Trait, _, _) => "trait",
ModuleKind::Block(..) => "block",
_ => "enum",
};
let old_noun = match old_binding.is_import() {
true => "import",
false => "definition",
};
let new_participle = match new_binding.is_import() {
true => "imported",
false => "defined",
};
let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
if let Some(s) = self.name_already_seen.get(&name) {
if s == &span {
return;
}
}
let old_kind = match (ns, old_binding.module()) {
(ValueNS, _) => "value",
(MacroNS, _) => "macro",
(TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
(TypeNS, Some(module)) if module.is_normal() => "module",
(TypeNS, Some(module)) if module.is_trait() => "trait",
(TypeNS, _) => "type",
};
let msg = format!("the name `{}` is defined multiple times", name);
let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
(true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
(true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
true => struct_span_err!(self.session, span, E0254, "{}", msg),
false => struct_span_err!(self.session, span, E0260, "{}", msg),
},
_ => match (old_binding.is_import(), new_binding.is_import()) {
(false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
(true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
_ => struct_span_err!(self.session, span, E0255, "{}", msg),
},
};
err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
name,
ns.descr(),
container));
err.span_label(span, format!("`{}` re{} here", name, new_participle));
err.span_label(
self.session.source_map().def_span(old_binding.span),
format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
);
// See https://github.com/rust-lang/rust/issues/32354
use NameBindingKind::Import;
let directive = match (&new_binding.kind, &old_binding.kind) {
// If there are two imports where one or both have attributes then prefer removing the
// import without attributes.
(Import { directive: new, .. }, Import { directive: old, .. }) if {
!new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
(new.has_attributes || old.has_attributes)
} => {
if old.has_attributes {
Some((new, new_binding.span, true))
} else {
Some((old, old_binding.span, true))
}
},
// Otherwise prioritize the new binding.
(Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
Some((directive, new_binding.span, other.is_import())),
(other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
Some((directive, old_binding.span, other.is_import())),
_ => None,
};
// Check if the target of the use for both bindings is the same.
let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
let from_item = self.extern_prelude.get(&ident)
.map(|entry| entry.introduced_by_item)
.unwrap_or(true);
// Only suggest removing an import if both bindings are to the same def, if both spans
// aren't dummy spans. Further, if both bindings are imports, then the ident must have
// been introduced by a item.
let should_remove_import = duplicate && !has_dummy_span &&
((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
match directive {
Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
// Simple case - remove the entire import. Due to the above match arm, this can
// only be a single use so just remove it entirely.
err.tool_only_span_suggestion(
directive.use_span_with_attributes,
"remove unnecessary import",
String::new(),
Applicability::MaybeIncorrect,
);
},
Some((directive, span, _)) =>
self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
_ => {},
}
err.emit();
self.name_already_seen.insert(name, span);
}
/// This function adds a suggestion to change the binding name of a new import that conflicts
/// with an existing import.
///
/// ```ignore (diagnostic)
/// help: you can use `as` to change the binding name of the import
/// |
/// LL | use foo::bar as other_bar;
/// | ^^^^^^^^^^^^^^^^^^^^^
/// ```
fn add_suggestion_for_rename_of_use(
&self,
err: &mut DiagnosticBuilder<'_>,
name: Name,
directive: &ImportDirective<'_>,
binding_span: Span,
) {
let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
format!("Other{}", name)
} else {
format!("other_{}", name)
};
let mut suggestion = None;
match directive.subclass {
ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
suggestion = Some(format!("self as {}", suggested_name)),
ImportDirectiveSubclass::SingleImport { source, .. } => {
if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
.map(|pos| pos as usize) {
if let Ok(snippet) = self.session.source_map()
.span_to_snippet(binding_span) {
if pos <= snippet.len() {
suggestion = Some(format!(
"{} as {}{}",
&snippet[..pos],
suggested_name,
if snippet.ends_with(";") { ";" } else { "" }
))
}
}
}
}
ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
suggestion = Some(format!(
"extern crate {} as {};",
source.unwrap_or(target.name),
suggested_name,
)),
_ => unreachable!(),
}
let rename_msg = "you can use `as` to change the binding name of the import";
if let Some(suggestion) = suggestion {
err.span_suggestion(
binding_span,
rename_msg,
suggestion,
Applicability::MaybeIncorrect,
);
} else {
err.span_label(binding_span, rename_msg);
}
}
/// This function adds a suggestion to remove a unnecessary binding from an import that is
/// nested. In the following example, this function will be invoked to remove the `a` binding
/// in the second use statement:
///
/// ```ignore (diagnostic)
/// use issue_52891::a;
/// use issue_52891::{d, a, e};
/// ```
///
/// The following suggestion will be added:
///
/// ```ignore (diagnostic)
/// use issue_52891::{d, a, e};
/// ^-- help: remove unnecessary import
/// ```
///
/// If the nested use contains only one import then the suggestion will remove the entire
/// line.
///
/// It is expected that the directive provided is a nested import - this isn't checked by the
/// function. If this invariant is not upheld, this function's behaviour will be unexpected
/// as characters expected by span manipulations won't be present.
fn add_suggestion_for_duplicate_nested_use(
&self,
err: &mut DiagnosticBuilder<'_>,
directive: &ImportDirective<'_>,
binding_span: Span,
) {
assert!(directive.is_nested());
let message = "remove unnecessary import";
// Two examples will be used to illustrate the span manipulations we're doing:
//
// - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
// `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
// - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
// `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
let (found_closing_brace, span) = find_span_of_binding_until_next_binding(
self.session, binding_span, directive.use_span,
);
// If there was a closing brace then identify the span to remove any trailing commas from
// previous imports.
if found_closing_brace {
if let Some(span) = extend_span_to_previous_binding(self.session, span) {
err.tool_only_span_suggestion(span, message, String::new(),
Applicability::MaybeIncorrect);
} else {
// Remove the entire line if we cannot extend the span back, this indicates a
// `issue_52891::{self}` case.
err.span_suggestion(directive.use_span_with_attributes, message, String::new(),
Applicability::MaybeIncorrect);
}
return;
}
err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
}
fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
-> Option<&'a NameBinding<'a>> {
if ident.is_path_segment_keyword() {
// Make sure `self`, `super` etc produce an error when passed to here.
return None;
}
self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
if let Some(binding) = entry.extern_crate_item {
if !speculative && entry.introduced_by_item {
self.record_use(ident, TypeNS, binding, false);
}
Some(binding)
} else {
let crate_id = if !speculative {
self.crate_loader.process_path_extern(ident.name, ident.span)
} else if let Some(crate_id) =
self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
crate_id
} else {
return None;
};
let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
Some((crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
.to_name_binding(self.arenas))
}
})
}
/// 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,
/// just that an error occurred.
// FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
pub fn resolve_str_path_error(
&mut self, span: Span, path_str: &str, ns: Namespace, module_id: NodeId
) -> Result<(ast::Path, Res), ()> {
let path = if path_str.starts_with("::") {
ast::Path {
span,
segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
.chain({
path_str.split("::").skip(1).map(Ident::from_str)
})
.map(|i| self.new_ast_path_segment(i))
.collect(),
}
} else {
ast::Path {
span,
segments: path_str
.split("::")
.map(Ident::from_str)
.map(|i| self.new_ast_path_segment(i))
.collect(),
}
};
let module = self.block_map.get(&module_id).copied().unwrap_or_else(|| {
let def_id = self.definitions.local_def_id(module_id);
self.module_map.get(&def_id).copied().unwrap_or(self.graph_root)
});
let parent_scope = &ParentScope::module(module);
let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
Ok((path, res))
}
// Resolve a path passed from rustdoc or HIR lowering.
fn resolve_ast_path(
&mut self,
path: &ast::Path,
ns: Namespace,
parent_scope: &ParentScope<'a>,
) -> Result<Res, (Span, ResolutionError<'a>)> {
match self.resolve_path(
&Segment::from_path(path), Some(ns), parent_scope, true, path.span, CrateLint::No
) {
PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
Ok(module.res().unwrap()),
PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
Ok(path_res.base_res()),
PathResult::NonModule(..) => {
Err((path.span, ResolutionError::FailedToResolve {
label: String::from("type-relative paths are not supported in this context"),
suggestion: None,
}))
}
PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
PathResult::Failed { span, label, suggestion, .. } => {
Err((span, ResolutionError::FailedToResolve {
label,
suggestion,
}))
}
}
}
fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
let mut seg = ast::PathSegment::from_ident(ident);
seg.id = self.session.next_node_id();
seg
}
}
fn names_to_string(names: &[Name]) -> String {
let mut result = String::new();
for (i, name) in names.iter()
.filter(|name| **name != kw::PathRoot)
.enumerate() {
if i > 0 {
result.push_str("::");
}
result.push_str(&name.as_str());
}
result
}
fn path_names_to_string(path: &Path) -> String {
names_to_string(&path.segments.iter()
.map(|seg| seg.ident.name)
.collect::<Vec<_>>())
}
/// A somewhat inefficient routine to obtain the name of a module.
fn module_to_string(module: Module<'_>) -> Option<String> {
let mut names = Vec::new();
fn collect_mod(names: &mut Vec<Name>, module: Module<'_>) {
if let ModuleKind::Def(.., name) = module.kind {
if let Some(parent) = module.parent {
names.push(name);
collect_mod(names, parent);
}
} else {
names.push(Name::intern("<opaque>"));
collect_mod(names, module.parent.unwrap());
}
}
collect_mod(&mut names, module);
if names.is_empty() {
return None;
}
names.reverse();
Some(names_to_string(&names))
}
#[derive(Copy, Clone, Debug)]
enum CrateLint {
/// Do not issue the lint.
No,
/// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
/// In this case, we can take the span of that path.
SimplePath(NodeId),
/// This lint comes from a `use` statement. In this case, what we
/// care about really is the *root* `use` statement; e.g., if we
/// have nested things like `use a::{b, c}`, we care about the
/// `use a` part.
UsePath { root_id: NodeId, root_span: Span },
/// This is the "trait item" from a fully qualified path. For example,
/// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
/// The `path_span` is the span of the to the trait itself (`X::Y`).
QPathTrait { qpath_id: NodeId, qpath_span: Span },
}
impl CrateLint {
fn node_id(&self) -> Option<NodeId> {
match *self {
CrateLint::No => None,
CrateLint::SimplePath(id) |
CrateLint::UsePath { root_id: id, .. } |
CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
}
}
}