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fuchsia / third_party / rust / e656e609ba8794997d466f764d83374de61b8eea / . / compiler / rustc_resolve / src / lib.rs
blob: b12e516fa3ed5371f360c99a5935ed4ad1a913f8 [file] [log] [blame]
// ignore-tidy-filelength
//! 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 and lifetime names are resolved here as well.
//!
//! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(bool_to_option)]
#![feature(crate_visibility_modifier)]
#![feature(nll)]
#![feature(or_patterns)]
#![recursion_limit = "256"]
pub use rustc_hir::def::{Namespace, PerNS};
use Determinacy::*;
use rustc_arena::{DroplessArena, TypedArena};
use rustc_ast::node_id::NodeMap;
use rustc_ast::unwrap_or;
use rustc_ast::visit::{self, Visitor};
use rustc_ast::{self as ast, FloatTy, IntTy, NodeId, UintTy};
use rustc_ast::{Crate, CRATE_NODE_ID};
use rustc_ast::{ItemKind, Path};
use rustc_ast_lowering::ResolverAstLowering;
use rustc_ast_pretty::pprust;
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
use rustc_data_structures::ptr_key::PtrKey;
use rustc_data_structures::sync::Lrc;
use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
use rustc_expand::base::SyntaxExtension;
use rustc_hir::def::Namespace::*;
use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
use rustc_hir::TraitCandidate;
use rustc_index::vec::IndexVec;
use rustc_metadata::creader::{CStore, CrateLoader};
use rustc_middle::hir::exports::ExportMap;
use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
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;
use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
use rustc_span::source_map::Spanned;
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{Span, DUMMY_SP};
use smallvec::{smallvec, SmallVec};
use std::cell::{Cell, RefCell};
use std::collections::BTreeSet;
use std::{cmp, fmt, iter, ptr};
use tracing::debug;
use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
use imports::{Import, ImportKind, ImportResolver, NameResolution};
use late::{HasGenericParams, PathSource, Rib, RibKind::*};
use macros::{MacroRulesBinding, MacroRulesScope};
type Res = def::Res<NodeId>;
mod build_reduced_graph;
mod check_unused;
mod def_collector;
mod diagnostics;
mod imports;
mod late;
mod macros;
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(ExpnId),
DeriveHelpersCompat,
MacroRules(MacroRulesScope<'a>),
CrateRoot,
Module(Module<'a>),
RegisteredAttrs,
MacroUsePrelude,
BuiltinAttrs,
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,
macro_rules: MacroRulesScope<'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(),
macro_rules: MacroRulesScope::Empty,
derives: &[],
}
}
}
#[derive(Eq)]
struct BindingError {
name: Symbol,
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, HasGenericParams),
/// Error E0403: the name is already used for a type or const parameter in this generic
/// parameter list.
NameAlreadyUsedInParameterList(Symbol, Span),
/// Error E0407: method is not a member of trait.
MethodNotMemberOfTrait(Symbol, &'a str),
/// Error E0437: type is not a member of trait.
TypeNotMemberOfTrait(Symbol, &'a str),
/// Error E0438: const is not a member of trait.
ConstNotMemberOfTrait(Symbol, &'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(Symbol, Span),
/// Error E0415: identifier is bound more than once in this parameter list.
IdentifierBoundMoreThanOnceInParameterList(Symbol),
/// Error E0416: identifier is bound more than once in the same pattern.
IdentifierBoundMoreThanOnceInSamePattern(Symbol),
/// Error E0426: use of undeclared label.
UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
/// Error E0429: `self` imports are only allowed within a `{ }` list.
SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
/// 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(&'static str, Symbol, &'a NameBinding<'a>),
/// Error E0128: type parameters with a default cannot use forward-declared identifiers.
ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
/// ERROR E0770: the type of const parameters must not depend on other generic parameters.
ParamInTyOfConstParam(Symbol),
/// constant values inside of type parameter defaults must not depend on generic parameters.
ParamInAnonConstInTyDefault(Symbol),
/// generic parameters must not be used inside const evaluations.
///
/// This error is only emitted when using `min_const_generics`.
ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
/// Error E0735: type parameters with a default cannot use `Self`
SelfInTyParamDefault,
/// Error E0767: use of unreachable label
UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
}
enum VisResolutionError<'a> {
Relative2018(Span, &'a ast::Path),
AncestorOnly(Span),
FailedToResolve(Span, String, Option<Suggestion>),
ExpectedFound(Span, String, Res),
Indeterminate(Span),
ModuleOnly(Span),
}
/// 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>,
/// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
/// nonsensical suggestions.
has_generic_args: bool,
}
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, has_generic_args: false }
}
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), has_generic_args: seg.args.is_some() }
}
}
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.kind {
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 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, Symbol),
}
impl ModuleKind {
/// Get name of the module.
pub fn name(&self) -> Option<Symbol> {
match self {
ModuleKind::Block(..) => None,
ModuleKind::Def(.., name) => Some(*name),
}
}
}
/// A key that identifies a binding in a given `Module`.
///
/// Multiple bindings in the same module can have the same key (in a valid
/// program) if all but one of them come from glob imports.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
struct BindingKey {
/// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
/// identifier.
ident: Ident,
ns: Namespace,
/// 0 if ident is not `_`, otherwise a value that's unique to the specific
/// `_` in the expanded AST that introduced this binding.
disambiguator: u32,
}
type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'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 Import<'a>>>,
globs: RefCell<Vec<&'a Import<'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 (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
if let Some(binding) = name_resolution.borrow().binding {
f(resolver, key.ident, key.ns, binding);
}
}
}
/// This modifies `self` in place. The traits will be stored in `self.traits`.
fn ensure_traits<R>(&'a self, resolver: &mut R)
where
R: AsMut<Resolver<'a>>,
{
let mut traits = self.traits.borrow_mut();
if traits.is_none() {
let mut collected_traits = Vec::new();
self.for_each_child(resolver, |_, name, ns, binding| {
if ns != TypeNS {
return;
}
if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
collected_traits.push((name, binding))
}
});
*traits = Some(collected_traits.into_boxed_slice());
}
}
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 | 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>, import: &'a Import<'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> {
ident: Ident,
binding: &'a NameBinding<'a>,
dedup_span: Span,
}
struct UseError<'a> {
err: DiagnosticBuilder<'a>,
/// Candidates which user could `use` to access the missing type.
candidates: Vec<ImportSuggestion>,
/// The `DefId` of the module to place the use-statements in.
def_id: DefId,
/// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
instead: bool,
/// Extra free-form suggestion.
suggestion: Option<(Span, &'static str, String, Applicability)>,
}
#[derive(Clone, Copy, PartialEq, Debug)]
enum AmbiguityKind {
Import,
BuiltinAttr,
DeriveHelper,
MacroRulesVsModularized,
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::MacroRulesVsModularized => {
"`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,
}
}
fn is_possibly_imported_variant(&self) -> bool {
match self.kind {
NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
_ => self.is_variant(),
}
}
// 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 | DefKind::Ctor(CtorOf::Variant, ..), _),
_,
) => true,
_ => false,
}
}
fn is_extern_crate(&self) -> bool {
match self.kind {
NameBindingKind::Import {
import: &Import { kind: ImportKind::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 { import, .. } => import.is_glob(),
_ => false,
}
}
fn is_importable(&self) -> bool {
match self.res() {
Res::Def(DefKind::AssocConst | DefKind::AssocFn | 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<Symbol, 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,
}
/// Used for better errors for E0773
enum BuiltinMacroState {
NotYetSeen(SyntaxExtension),
AlreadySeen(Span),
}
/// The main resolver class.
///
/// This is the visitor that walks the whole crate.
pub struct Resolver<'a> {
session: &'a Session,
definitions: Definitions,
graph_root: Module<'a>,
prelude: Option<Module<'a>>,
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<Spanned<Symbol>>>,
/// All imports known to succeed or fail.
determined_imports: Vec<&'a Import<'a>>,
/// All non-determined imports.
indeterminate_imports: Vec<&'a Import<'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.
unusable_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>,
/// `CrateNum` resolutions of `extern crate` items.
extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
export_map: ExportMap<LocalDefId>,
trait_map: NodeMap<Vec<TraitCandidate>>,
/// 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<LocalDefId, Module<'a>>,
extern_module_map: FxHashMap<DefId, Module<'a>>,
binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
underscore_disambiguator: u32,
/// Maps glob imports to the names of items actually imported.
glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
/// Visibilities in "lowered" form, for all entities that have them.
visibilities: FxHashMap<LocalDefId, ty::Visibility>,
used_imports: FxHashSet<(NodeId, Namespace)>,
maybe_unused_trait_imports: FxHashSet<LocalDefId>,
maybe_unused_extern_crates: Vec<(LocalDefId, 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: CrateLoader<'a>,
macro_names: FxHashSet<Ident>,
builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
registered_attrs: FxHashSet<Ident>,
registered_tools: FxHashSet<Ident>,
macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
all_macros: FxHashMap<Symbol, Res>,
macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
dummy_ext_bang: Lrc<SyntaxExtension>,
dummy_ext_derive: Lrc<SyntaxExtension>,
non_macro_attrs: [Lrc<SyntaxExtension>; 2],
local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
proc_macro_stubs: FxHashSet<LocalDefId>,
/// 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>)>,
/// `derive(Copy)` marks 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.
containers_deriving_copy: FxHashSet<ExpnId>,
/// 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>>,
/// `macro_rules` scopes *produced* by expanding the macro invocations,
/// include all the `macro_rules` items and other invocations generated by them.
output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScope<'a>>,
/// Helper attributes that are in scope for the given expansion.
helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
/// Avoid duplicated errors for "name already defined".
name_already_seen: FxHashMap<Symbol, Span>,
potentially_unused_imports: Vec<&'a Import<'a>>,
/// Table for mapping struct IDs into struct constructor IDs,
/// it's not used during normal resolution, only for better error reporting.
/// Also includes of list of each fields visibility
struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
/// Features enabled for this crate.
active_features: FxHashSet<Symbol>,
lint_buffer: LintBuffer,
next_node_id: NodeId,
def_id_to_span: IndexVec<LocalDefId, Span>,
node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
/// Indices of unnamed struct or variant fields with unresolved attributes.
placeholder_field_indices: FxHashMap<NodeId, usize>,
/// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
/// we know what parent node that fragment should be attached to thanks to this table.
invocation_parents: FxHashMap<ExpnId, LocalDefId>,
next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
/// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
/// FIXME: Replace with a more general AST map (together with some other fields).
trait_impl_items: FxHashSet<LocalDefId>,
}
/// Nothing really interesting here; it just provides memory for the rest of the crate.
#[derive(Default)]
pub struct ResolverArenas<'a> {
modules: TypedArena<ModuleData<'a>>,
local_modules: RefCell<Vec<Module<'a>>>,
imports: TypedArena<Import<'a>>,
name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
ast_paths: TypedArena<ast::Path>,
dropless: DroplessArena,
}
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.dropless.alloc(name_binding)
}
fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
self.imports.alloc(import)
}
fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
self.name_resolutions.alloc(Default::default())
}
fn alloc_macro_rules_binding(
&'a self,
binding: MacroRulesBinding<'a>,
) -> &'a MacroRulesBinding<'a> {
self.dropless.alloc(binding)
}
fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
self.ast_paths.alloc_from_iter(paths.iter().cloned())
}
fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
self.dropless.alloc_from_iter(spans)
}
}
impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
fn as_mut(&mut self) -> &mut Resolver<'a> {
self
}
}
impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
fn parent(self, id: DefId) -> Option<DefId> {
match id.as_local() {
Some(id) => self.definitions.def_key(id).parent,
None => 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 ResolverAstLowering for Resolver<'_> {
fn def_key(&mut self, id: DefId) -> DefKey {
if let Some(id) = id.as_local() {
self.definitions().def_key(id)
} else {
self.cstore().def_key(id)
}
}
fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
self.cstore().item_generics_num_lifetimes(def_id, sess)
}
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 lint_buffer(&mut self) -> &mut LintBuffer {
&mut self.lint_buffer
}
fn next_node_id(&mut self) -> NodeId {
self.next_node_id()
}
fn trait_map(&self) -> &NodeMap<Vec<TraitCandidate>> {
&self.trait_map
}
fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
self.node_id_to_def_id.get(&node).copied()
}
fn local_def_id(&self, node: NodeId) -> LocalDefId {
self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
}
/// Adds a definition with a parent definition.
fn create_def(
&mut self,
parent: LocalDefId,
node_id: ast::NodeId,
data: DefPathData,
expn_id: ExpnId,
span: Span,
) -> LocalDefId {
assert!(
!self.node_id_to_def_id.contains_key(&node_id),
"adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
node_id,
data,
self.definitions.def_key(self.node_id_to_def_id[&node_id]),
);
// Find the next free disambiguator for this key.
let next_disambiguator = &mut self.next_disambiguator;
let next_disambiguator = |parent, data| {
let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
let disambiguator = *next_disamb;
*next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
disambiguator
};
let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
assert_eq!(self.def_id_to_span.push(span), def_id);
// Some things for which we allocate `LocalDefId`s don't correspond to
// anything in the AST, so they don't have a `NodeId`. For these cases
// we don't need a mapping from `NodeId` to `LocalDefId`.
if node_id != ast::DUMMY_NODE_ID {
debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
self.node_id_to_def_id.insert(node_id, def_id);
}
assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
def_id
}
}
impl<'a> Resolver<'a> {
pub fn new(
session: &'a Session,
krate: &Crate,
crate_name: &str,
metadata_loader: &'a MetadataLoaderDyn,
arenas: &'a ResolverArenas<'a>,
) -> Resolver<'a> {
let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
let root_def_id = root_local_def_id.to_def_id();
let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
let graph_root = arenas.alloc_module(ModuleData {
no_implicit_prelude: session.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(root_local_def_id, graph_root);
let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
let root = definitions.get_root_def();
let mut visibilities = FxHashMap::default();
visibilities.insert(root_local_def_id, ty::Visibility::Public);
let mut def_id_to_span = IndexVec::default();
assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
let mut def_id_to_node_id = IndexVec::default();
assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
let mut node_id_to_def_id = FxHashMap::default();
node_id_to_def_id.insert(CRATE_NODE_ID, root);
let mut invocation_parents = FxHashMap::default();
invocation_parents.insert(ExpnId::root(), root);
let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
.opts
.externs
.iter()
.filter(|(_, entry)| entry.add_prelude)
.map(|(name, _)| (Ident::from_str(name), Default::default()))
.collect();
if !session.contains_name(&krate.attrs, sym::no_core) {
extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
if !session.contains_name(&krate.attrs, sym::no_std) {
extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
}
}
let (registered_attrs, registered_tools) =
macros::registered_attrs_and_tools(session, &krate.attrs);
let mut invocation_parent_scopes = FxHashMap::default();
invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
let features = session.features_untracked();
let non_macro_attr =
|mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
Resolver {
session,
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,
unusable_binding: None,
primitive_type_table: PrimitiveTypeTable::new(),
partial_res_map: Default::default(),
import_res_map: Default::default(),
label_res_map: Default::default(),
extern_crate_map: Default::default(),
export_map: FxHashMap::default(),
trait_map: Default::default(),
underscore_disambiguator: 0,
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(),
visibilities,
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: CrateLoader::new(session, metadata_loader, crate_name),
macro_names: FxHashSet::default(),
builtin_macros: Default::default(),
registered_attrs,
registered_tools,
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_macro_rules_scopes: Default::default(),
helper_attrs: Default::default(),
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(),
containers_deriving_copy: Default::default(),
active_features: features
.declared_lib_features
.iter()
.map(|(feat, ..)| *feat)
.chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
.collect(),
lint_buffer: LintBuffer::default(),
next_node_id: NodeId::from_u32(1),
def_id_to_span,
node_id_to_def_id,
def_id_to_node_id,
placeholder_field_indices: Default::default(),
invocation_parents,
next_disambiguator: Default::default(),
trait_impl_items: Default::default(),
}
}
pub fn next_node_id(&mut self) -> NodeId {
let next = self
.next_node_id
.as_usize()
.checked_add(1)
.expect("input too large; ran out of NodeIds");
self.next_node_id = ast::NodeId::from_usize(next);
self.next_node_id
}
pub fn lint_buffer(&mut self) -> &mut LintBuffer {
&mut self.lint_buffer
}
pub fn arenas() -> ResolverArenas<'a> {
Default::default()
}
pub fn into_outputs(self) -> ResolverOutputs {
let definitions = self.definitions;
let visibilities = self.visibilities;
let extern_crate_map = self.extern_crate_map;
let export_map = self.export_map;
let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
let glob_map = self.glob_map;
ResolverOutputs {
definitions: definitions,
cstore: Box::new(self.crate_loader.into_cstore()),
visibilities,
extern_crate_map,
export_map,
glob_map,
maybe_unused_trait_imports,
maybe_unused_extern_crates,
extern_prelude: self
.extern_prelude
.iter()
.map(|(ident, entry)| (ident.name, entry.introduced_by_item))
.collect(),
}
}
pub fn clone_outputs(&self) -> ResolverOutputs {
ResolverOutputs {
definitions: self.definitions.clone(),
cstore: Box::new(self.cstore().clone()),
visibilities: self.visibilities.clone(),
extern_crate_map: self.extern_crate_map.clone(),
export_map: self.export_map.clone(),
glob_map: self.glob_map.clone(),
maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
extern_prelude: self
.extern_prelude
.iter()
.map(|(ident, entry)| (ident.name, entry.introduced_by_item))
.collect(),
}
}
pub fn cstore(&self) -> &CStore {
self.crate_loader.cstore()
}
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 ctxt.outer_expn().expn_data().macro_def_id {
Some(def_id) => return def_id,
None => ctxt.remove_mark(),
};
}
}
/// Entry point to crate resolution.
pub fn resolve_crate(&mut self, krate: &Crate) {
let _prof_timer = self.session.prof.generic_activity("resolve_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 get_traits_in_module_containing_item(
&mut self,
ident: Ident,
ns: Namespace,
module: Module<'a>,
found_traits: &mut Vec<TraitCandidate>,
parent_scope: &ParentScope<'a>,
) {
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?")
}
}
}
fn find_transitive_imports(
&mut self,
mut kind: &NameBindingKind<'_>,
trait_name: Ident,
) -> SmallVec<[LocalDefId; 1]> {
let mut import_ids = smallvec![];
while let NameBindingKind::Import { import, binding, .. } = kind {
let id = self.local_def_id(import.id);
self.maybe_unused_trait_imports.insert(id);
self.add_to_glob_map(&import, trait_name);
import_ids.push(id);
kind = &binding.kind;
}
import_ids
}
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 new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
let ident = ident.normalize_to_macros_2_0();
let disambiguator = if ident.name == kw::Underscore {
self.underscore_disambiguator += 1;
self.underscore_disambiguator
} else {
0
};
BindingKey { ident, ns, disambiguator }
}
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>,
key: BindingKey,
) -> &'a RefCell<NameResolution<'a>> {
*self
.resolutions(module)
.borrow_mut()
.entry(key)
.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 { import, 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.normalize_to_macros_2_0()) {
if let Some(crate_item) = entry.extern_crate_item {
if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
return;
}
}
}
}
used.set(true);
import.used.set(true);
self.used_imports.insert((import.id, ns));
self.add_to_glob_map(&import, ident);
self.record_use(ident, ns, binding, false);
}
}
#[inline]
fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
if import.is_glob() {
let def_id = self.local_def_id(import.id);
self.glob_map.entry(def_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 `macro_rules` 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).
let rust_2015 = ident.span.rust_2015();
let (ns, macro_kind, is_absolute_path) = match scope_set {
ScopeSet::All(ns, _) => (ns, None, false),
ScopeSet::AbsolutePath(ns) => (ns, None, true),
ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), 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(parent_scope.expansion),
};
let mut ident = ident.normalize_to_macros_2_0();
let mut use_prelude = !module.no_implicit_prelude;
loop {
let visit = match scope {
// Derive helpers are not in scope when resolving derives in the same container.
Scope::DeriveHelpers(expn_id) => {
!(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
}
Scope::DeriveHelpersCompat => true,
Scope::MacroRules(..) => true,
Scope::CrateRoot => true,
Scope::Module(..) => true,
Scope::RegisteredAttrs => use_prelude,
Scope::MacroUsePrelude => use_prelude || rust_2015,
Scope::BuiltinAttrs => true,
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(expn_id) if expn_id != ExpnId::root() => {
// Derive helpers are not visible to code generated by bang or derive macros.
let expn_data = expn_id.expn_data();
match expn_data.kind {
ExpnKind::Root
| ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
Scope::DeriveHelpersCompat
}
_ => Scope::DeriveHelpers(expn_data.parent),
}
}
Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
Scope::MacroRules(macro_rules_scope) => match macro_rules_scope {
MacroRulesScope::Binding(binding) => {
Scope::MacroRules(binding.parent_macro_rules_scope)
}
MacroRulesScope::Invocation(invoc_id) => Scope::MacroRules(
self.output_macro_rules_scopes
.get(&invoc_id)
.cloned()
.unwrap_or(self.invocation_parent_scopes[&invoc_id].macro_rules),
),
MacroRulesScope::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::RegisteredAttrs,
}
}
}
}
Scope::RegisteredAttrs => Scope::MacroUsePrelude,
Scope::MacroUsePrelude => Scope::StdLibPrelude,
Scope::BuiltinAttrs => 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, normalized_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 normalized_span = ident.span.normalize_to_macros_2_0();
(normalized_span, normalized_span)
} else {
(ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
};
ident.span = general_span;
let normalized_ident = Ident { span: normalized_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
// (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
let rib_ident = if ribs[i].kind.contains_params() { normalized_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,
rib_ident,
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 = normalized_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.lint_buffer.buffer_lint_with_diagnostic(
lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
node_id,
ident.span,
&format!("cannot find {} `{}` in this scope", ns.descr(), ident),
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 let Some(ident) = self.registered_tools.get(&ident) {
let binding =
(Res::ToolMod, ty::Visibility::Public, ident.span, 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));
}
}
}
if ns == TypeNS {
if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
let binding =
(Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
.to_name_binding(self.arenas);
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) = module.expansion.expn_data().macro_def_id {
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.normalize_to_macros_2_0_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.normalize_to_macros_2_0_and_adjust(ExpnId::root());
}
ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
// No adjustments
}
}
self.resolve_ident_in_module_unadjusted_ext(
module,
ident,
ns,
adjusted_parent_scope,
false,
record_used,
path_span,
)
}
fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
debug!("resolve_crate_root({:?})", ident);
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 opaque 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.normalize_to_macro_rules();
debug!(
"resolve_crate_root: marks={:?}",
ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
);
let mut iter = ctxt.marks().into_iter().rev().peekable();
let mut result = None;
// Find the last opaque 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;
}
}
debug!(
"resolve_crate_root: found opaque mark {:?} {:?}",
result,
result.map(|r| r.expn_data())
);
// Then find the last semi-transparent mark from the end if it exists.
for (mark, transparency) in iter {
if transparency == Transparency::SemiTransparent {
result = Some(mark);
} else {
break;
}
}
debug!(
"resolve_crate_root: found semi-transparent mark {:?} {:?}",
result,
result.map(|r| r.expn_data())
);
result
} else {
debug!("resolve_crate_root: not DollarCrate");
ctxt = ctxt.normalize_to_macros_2_0();
ctxt.adjust(ExpnId::root())
};
let module = match mark {
Some(def) => self.macro_def_scope(def),
None => {
debug!(
"resolve_crate_root({:?}): found no mark (ident.span = {:?})",
ident, ident.span
);
return self.graph_root;
}
};
let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id });
debug!(
"resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
ident,
module,
module.kind.name(),
ident.span
);
module
}
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().normalize_to_macros_2_0() != *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, has_generic_args: _ }) 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().normalize_to_macros_2_0();
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 leading `super` keywords".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().normalize_to_macros_2_0();
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,
};
}
enum FindBindingResult<'a> {
Binding(Result<&'a NameBinding<'a>, Determinacy>),
PathResult(PathResult<'a>),
}
let find_binding_in_ns = |this: &mut Self, ns| {
let binding = if let Some(module) = module {
this.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());
this.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 this.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(this, res);
return FindBindingResult::PathResult(PathResult::NonModule(
PartialRes::with_unresolved_segments(res, path.len() - 1),
));
}
_ => Err(Determinacy::determined(record_used)),
}
};
FindBindingResult::Binding(binding)
};
let binding = match find_binding_in_ns(self, ns) {
FindBindingResult::PathResult(x) => return x,
FindBindingResult::Binding(binding) => binding,
};
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,
};
// Don't look up import candidates if this is a speculative resolve
let mut candidates = if record_used {
self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
} else {
Vec::new()
};
candidates.sort_by_cached_key(|c| {
(c.path.segments.len(), pprust::path_to_string(&c.path))
});
if let Some(candidate) = candidates.get(0) {
(
String::from("unresolved import"),
Some((
vec![(ident.span, pprust::path_to_string(&candidate.path))],
String::from("a similar path exists"),
Applicability::MaybeIncorrect,
)),
)
} else {
(format!("maybe a missing crate `{}`?", ident), None)
}
} else if i == 0 {
if ident
.name
.with(|n| n.chars().next().map_or(false, |c| c.is_ascii_uppercase()))
{
(format!("use of undeclared type `{}`", ident), None)
} else {
(format!("use of undeclared crate or module `{}`", ident), None)
}
} else {
let mut msg =
format!("could not find `{}` in `{}`", ident, path[i - 1].ident);
if ns == TypeNS || ns == ValueNS {
let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
if let FindBindingResult::Binding(Ok(binding)) =
find_binding_in_ns(self, ns_to_try)
{
let mut found = |what| {
msg = format!(
"expected {}, found {} `{}` in `{}`",
ns.descr(),
what,
ident,
path[i - 1].ident
)
};
if binding.module().is_some() {
found("module")
} else {
match binding.res() {
def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
_ => found(ns_to_try.descr()),
}
}
};
}
(msg, 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(
&mut 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 { import, .. } = binding.kind {
// Careful: we still want to rewrite paths from renamed extern crates.
if let ImportKind::ExternCrate { source: None, .. } = import.kind {
return;
}
}
}
let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
self.lint_buffer.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,
rib_ident: Ident,
mut 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 {
let res_error = if rib_ident.name == kw::SelfUpper {
ResolutionError::SelfInTyParamDefault
} else {
ResolutionError::ForwardDeclaredTyParam
};
self.report_error(span, res_error);
}
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
| ClosureOrAsyncRibKind
| ModuleRibKind(..)
| MacroDefinition(..)
| ForwardTyParamBanRibKind => {
// 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;
}
ConstParamTyRibKind => {
if record_used {
self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
}
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(..) => {
let mut in_ty_param_default = false;
for rib in ribs {
let has_generic_params = match rib.kind {
NormalRibKind
| ClosureOrAsyncRibKind
| AssocItemRibKind
| ModuleRibKind(..)
| MacroDefinition(..) => {
// Nothing to do. Continue.
continue;
}
// We only forbid constant items if we are inside of type defaults,
// for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
ForwardTyParamBanRibKind => {
in_ty_param_default = true;
continue;
}
ConstantItemRibKind(trivial) => {
// HACK(min_const_generics): We currently only allow `N` or `{ N }`.
if !trivial && self.session.features_untracked().min_const_generics {
// HACK(min_const_generics): If we encounter `Self` in an anonymous constant
// we can't easily tell if it's generic at this stage, so we instead remember
// this and then enforce the self type to be concrete later on.
if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
res = Res::SelfTy(trait_def, Some((impl_def, true)));
} else {
if record_used {
self.report_error(
span,
ResolutionError::ParamInNonTrivialAnonConst {
name: rib_ident.name,
is_type: true,
},
);
}
return Res::Err;
}
}
if in_ty_param_default {
if record_used {
self.report_error(
span,
ResolutionError::ParamInAnonConstInTyDefault(
rib_ident.name,
),
);
}
return Res::Err;
} else {
continue;
}
}
// This was an attempt to use a type parameter outside its scope.
ItemRibKind(has_generic_params) => has_generic_params,
FnItemRibKind => HasGenericParams::Yes,
ConstParamTyRibKind => {
if record_used {
self.report_error(
span,
ResolutionError::ParamInTyOfConstParam(rib_ident.name),
);
}
return Res::Err;
}
};
if record_used {
self.report_error(
span,
ResolutionError::GenericParamsFromOuterFunction(
res,
has_generic_params,
),
);
}
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();
}
let mut in_ty_param_default = false;
for rib in ribs {
let has_generic_params = match rib.kind {
NormalRibKind
| ClosureOrAsyncRibKind
| AssocItemRibKind
| ModuleRibKind(..)
| MacroDefinition(..) => continue,
// We only forbid constant items if we are inside of type defaults,
// for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
ForwardTyParamBanRibKind => {
in_ty_param_default = true;
continue;
}
ConstantItemRibKind(trivial) => {
// HACK(min_const_generics): We currently only allow `N` or `{ N }`.
if !trivial && self.session.features_untracked().min_const_generics {
if record_used {
self.report_error(
span,
ResolutionError::ParamInNonTrivialAnonConst {
name: rib_ident.name,
is_type: false,
},
);
}
return Res::Err;
}
if in_ty_param_default {
if record_used {
self.report_error(
span,
ResolutionError::ParamInAnonConstInTyDefault(
rib_ident.name,
),
);
}
return Res::Err;
} else {
continue;
}
}
ItemRibKind(has_generic_params) => has_generic_params,
FnItemRibKind => HasGenericParams::Yes,
ConstParamTyRibKind => {
if record_used {
self.report_error(
span,
ResolutionError::ParamInTyOfConstParam(rib_ident.name),
);
}
return Res::Err;
}
};
// This was an attempt to use a const parameter outside its scope.
if record_used {
self.report_error(
span,
ResolutionError::GenericParamsFromOuterFunction(
res,
has_generic_params,
),
);
}
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_macro_rules_vs_modularized(
&self,
macro_rules: &'a NameBinding<'a>,
modularized: &'a NameBinding<'a>,
) -> bool {
// Some non-controversial subset of ambiguities "modularized 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(macro_rules)),
self.binding_parent_modules.get(&PtrKey(modularized)),
) {
(Some(macro_rules), Some(modularized)) => {
macro_rules.normal_ancestor_id == modularized.normal_ancestor_id
&& modularized.is_ancestor_of(macro_rules)
}
_ => false,
}
}
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.lint_buffer.buffer_lint_with_diagnostic(
lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
CRATE_NODE_ID,
span_use,
msg,
BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
);
}
for ambiguity_error in &self.ambiguity_errors {
self.report_ambiguity_error(ambiguity_error);
}
let mut reported_spans = FxHashSet::default();
for error in &self.privacy_errors {
if reported_spans.insert(error.dedup_span) {
self.report_privacy_error(error);
}
}
}
fn report_with_use_injections(&mut self, krate: &Crate) {
for UseError { mut err, candidates, def_id, instead, suggestion } in
self.use_injections.drain(..)
{
let (span, found_use) = if let Some(def_id) = def_id.as_local() {
UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
} else {
(None, false)
};
if !candidates.is_empty() {
diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
} else if let Some((span, msg, sugg, appl)) = suggestion {
err.span_suggestion(span, msg, sugg, appl);
}
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(kind, _, _) => kind.descr(parent.def_id().unwrap()),
ModuleKind::Block(..) => "block",
};
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().guess_head_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().guess_head_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 import = 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 { import: new, .. }, Import { import: 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 { import, .. }, other) if !new_binding.span.is_dummy() => {
Some((import, new_binding.span, other.is_import()))
}
(other, Import { import, .. }) if !old_binding.span.is_dummy() => {
Some((import, 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 import {
Some((import, span, true)) if should_remove_import && import.is_nested() => {
self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
}
Some((import, _, true)) if should_remove_import && !import.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(
import.use_span_with_attributes,
"remove unnecessary import",
String::new(),
Applicability::MaybeIncorrect,
);
}
Some((import, span, _)) => {
self.add_suggestion_for_rename_of_use(&mut err, name, import, 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.
///
/// ```text,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: Symbol,
import: &Import<'_>,
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 import.kind {
ImportKind::Single { type_ns_only: true, .. } => {
suggestion = Some(format!("self as {}", suggested_name))
}
ImportKind::Single { 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 { "" }
))
}
}
}
}
ImportKind::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 provided import is nested - 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<'_>,
import: &Import<'_>,
binding_span: Span,
) {
assert!(import.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 `import.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 `import.use_span` is `issue_52891::{d, e, a};`.
let (found_closing_brace, span) =
find_span_of_binding_until_next_binding(self.session, binding_span, import.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(
import.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.normalize_to_macros_2_0()).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 {
self.crate_loader.maybe_process_path_extern(ident.name)?
};
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),
)
}
})
}
/// 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,
/// 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: DefId,
) -> 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(),
tokens: None,
}
} else {
ast::Path {
span,
segments: path_str
.split("::")
.map(Ident::from_str)
.map(|i| self.new_ast_path_segment(i))
.collect(),
tokens: None,
}
};
let module = self.get_module(module_id);
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,
false,
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(&mut self, ident: Ident) -> ast::PathSegment {
let mut seg = ast::PathSegment::from_ident(ident);
seg.id = self.next_node_id();
seg
}
// For rustdoc.
pub fn graph_root(&self) -> Module<'a> {
self.graph_root
}
// For rustdoc.
pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
&self.all_macros
}
/// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
#[inline]
pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
}
}
fn names_to_string(names: &[Symbol]) -> String {
let mut result = String::new();
for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
if i > 0 {
result.push_str("::");
}
if Ident::with_dummy_span(*name).is_raw_guess() {
result.push_str("r#");
}
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<Symbol>, 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(Symbol::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),
}
}
}
pub fn provide(providers: &mut Providers) {
late::lifetimes::provide(providers);
}