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fuchsia / third_party / rust / 31d631f84cc0cdb5f0dc9f1c430aeb511c47483d / . / src / librustc_resolve / lib.rs
blob: 5f571dc71eb774fb2cf67a2f6a4da34b0de22f87 [file] [log] [blame]
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
html_root_url = "https://doc.rust-lang.org/nightly/")]
#![feature(crate_visibility_modifier)]
#![feature(label_break_value)]
#![feature(nll)]
#![feature(rustc_diagnostic_macros)]
#![feature(slice_sort_by_cached_key)]
#[macro_use]
extern crate bitflags;
#[macro_use]
extern crate log;
#[macro_use]
extern crate syntax;
extern crate syntax_pos;
extern crate rustc_errors as errors;
extern crate arena;
#[macro_use]
extern crate rustc;
extern crate rustc_data_structures;
extern crate rustc_metadata;
pub use rustc::hir::def::{Namespace, PerNS};
use self::TypeParameters::*;
use self::RibKind::*;
use rustc::hir::map::{Definitions, DefCollector};
use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
use rustc::middle::cstore::CrateStore;
use rustc::session::Session;
use rustc::lint;
use rustc::hir::def::*;
use rustc::hir::def::Namespace::*;
use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
use rustc::session::config::nightly_options;
use rustc::ty;
use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
use rustc_metadata::creader::CrateLoader;
use rustc_metadata::cstore::CStore;
use syntax::source_map::SourceMap;
use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
use syntax::ext::base::SyntaxExtension;
use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
use syntax::ext::base::MacroKind;
use syntax::symbol::{Symbol, keywords};
use syntax::util::lev_distance::find_best_match_for_name;
use syntax::visit::{self, FnKind, Visitor};
use syntax::attr;
use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
use syntax::ptr::P;
use syntax_pos::{Span, DUMMY_SP, MultiSpan};
use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
use std::cell::{Cell, RefCell};
use std::{cmp, fmt, iter, mem, ptr};
use std::collections::BTreeSet;
use std::mem::replace;
use rustc_data_structures::ptr_key::PtrKey;
use rustc_data_structures::sync::Lrc;
use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
use macros::{InvocationData, LegacyBinding, ParentScope};
// NB: This module needs to be declared first so diagnostics are
// registered before they are used.
mod diagnostics;
mod error_reporting;
mod macros;
mod check_unused;
mod build_reduced_graph;
mod resolve_imports;
fn is_known_tool(name: Name) -> bool {
["clippy", "rustfmt"].contains(&&*name.as_str())
}
enum Weak {
Yes,
No,
}
enum ScopeSet {
Import(Namespace),
AbsolutePath(Namespace),
Macro(MacroKind),
Module,
}
/// A free importable items suggested in case of resolution failure.
struct ImportSuggestion {
path: Path,
}
/// A field or associated item from self type suggested in case of resolution failure.
enum AssocSuggestion {
Field,
MethodWithSelf,
AssocItem,
}
#[derive(Eq)]
struct BindingError {
name: Name,
origin: BTreeSet<Span>,
target: BTreeSet<Span>,
}
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 parameters from outer function
TypeParametersFromOuterFunction(Def),
/// error E0403: the name is already used for a type parameter in this type parameter list
NameAlreadyUsedInTypeParameterList(Name, &'a Span),
/// error E0407: method is not a member of trait
MethodNotMemberOfTrait(Name, &'a str),
/// error E0437: type is not a member of trait
TypeNotMemberOfTrait(Name, &'a str),
/// error E0438: const is not a member of trait
ConstNotMemberOfTrait(Name, &'a str),
/// error E0408: variable `{}` is not bound in all patterns
VariableNotBoundInPattern(&'a BindingError),
/// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
VariableBoundWithDifferentMode(Name, Span),
/// error E0415: identifier is bound more than once in this parameter list
IdentifierBoundMoreThanOnceInParameterList(&'a str),
/// error E0416: identifier is bound more than once in the same pattern
IdentifierBoundMoreThanOnceInSamePattern(&'a str),
/// error E0426: use of undeclared label
UndeclaredLabel(&'a str, Option<Name>),
/// error E0429: `self` imports are only allowed within a { } list
SelfImportsOnlyAllowedWithin,
/// error E0430: `self` import can only appear once in the list
SelfImportCanOnlyAppearOnceInTheList,
/// error E0431: `self` import can only appear in an import list with a non-empty prefix
SelfImportOnlyInImportListWithNonEmptyPrefix,
/// error E0433: failed to resolve
FailedToResolve(&'a str),
/// 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 Ys
BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
/// error E0128: type parameters with a default cannot use forward declared identifiers
ForwardDeclaredTyParam,
}
/// Combines an error with provided span and emits it
///
/// This takes the error provided, combines it with the span and any additional spans inside the
/// error and emits it.
fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
span: Span,
resolution_error: ResolutionError<'a>) {
resolve_struct_error(resolver, span, resolution_error).emit();
}
fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
span: Span,
resolution_error: ResolutionError<'a>)
-> DiagnosticBuilder<'sess> {
match resolution_error {
ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
let mut err = struct_span_err!(resolver.session,
span,
E0401,
"can't use type parameters from outer function");
err.span_label(span, "use of type variable from outer function");
let cm = resolver.session.source_map();
match outer_def {
Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
resolver.definitions.opt_span(def_id)
}) {
err.span_label(
reduce_impl_span_to_impl_keyword(cm, impl_span),
"`Self` type implicitly declared here, by this `impl`",
);
}
match (maybe_trait_defid, maybe_impl_defid) {
(Some(_), None) => {
err.span_label(span, "can't use `Self` here");
}
(_, Some(_)) => {
err.span_label(span, "use a type here instead");
}
(None, None) => bug!("`impl` without trait nor type?"),
}
return err;
},
Def::TyParam(typaram_defid) => {
if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
err.span_label(typaram_span, "type variable from outer function");
}
},
_ => {
bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
Def::TyParam")
}
}
// Try to retrieve the span of the function signature and generate a new message with
// a local type parameter
let sugg_msg = "try using a local type parameter instead";
if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
// Suggest the modification to the user
err.span_suggestion_with_applicability(
sugg_span,
sugg_msg,
new_snippet,
Applicability::MachineApplicable,
);
} else if let Some(sp) = cm.generate_fn_name_span(span) {
err.span_label(sp, "try adding a local type parameter in this method instead");
} else {
err.help("try using a local type parameter instead");
}
err
}
ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
let mut err = struct_span_err!(resolver.session,
span,
E0403,
"the name `{}` is already used for a type parameter \
in this type parameter list",
name);
err.span_label(span, "already used");
err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
err
}
ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
let mut err = struct_span_err!(resolver.session,
span,
E0407,
"method `{}` is not a member of trait `{}`",
method,
trait_);
err.span_label(span, format!("not a member of trait `{}`", trait_));
err
}
ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
let mut err = struct_span_err!(resolver.session,
span,
E0437,
"type `{}` is not a member of trait `{}`",
type_,
trait_);
err.span_label(span, format!("not a member of trait `{}`", trait_));
err
}
ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
let mut err = struct_span_err!(resolver.session,
span,
E0438,
"const `{}` is not a member of trait `{}`",
const_,
trait_);
err.span_label(span, format!("not a member of trait `{}`", trait_));
err
}
ResolutionError::VariableNotBoundInPattern(binding_error) => {
let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
let msp = MultiSpan::from_spans(target_sp.clone());
let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
let mut err = resolver.session.struct_span_err_with_code(
msp,
&msg,
DiagnosticId::Error("E0408".into()),
);
for sp in target_sp {
err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
}
let origin_sp = binding_error.origin.iter().cloned();
for sp in origin_sp {
err.span_label(sp, "variable not in all patterns");
}
err
}
ResolutionError::VariableBoundWithDifferentMode(variable_name,
first_binding_span) => {
let mut err = struct_span_err!(resolver.session,
span,
E0409,
"variable `{}` is bound in inconsistent \
ways within the same match arm",
variable_name);
err.span_label(span, "bound in different ways");
err.span_label(first_binding_span, "first binding");
err
}
ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
let mut err = struct_span_err!(resolver.session,
span,
E0415,
"identifier `{}` is bound more than once in this parameter list",
identifier);
err.span_label(span, "used as parameter more than once");
err
}
ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
let mut err = struct_span_err!(resolver.session,
span,
E0416,
"identifier `{}` is bound more than once in the same pattern",
identifier);
err.span_label(span, "used in a pattern more than once");
err
}
ResolutionError::UndeclaredLabel(name, lev_candidate) => {
let mut err = struct_span_err!(resolver.session,
span,
E0426,
"use of undeclared label `{}`",
name);
if let Some(lev_candidate) = lev_candidate {
err.span_label(span, format!("did you mean `{}`?", lev_candidate));
} else {
err.span_label(span, format!("undeclared label `{}`", name));
}
err
}
ResolutionError::SelfImportsOnlyAllowedWithin => {
struct_span_err!(resolver.session,
span,
E0429,
"{}",
"`self` imports are only allowed within a { } list")
}
ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
let mut err = struct_span_err!(resolver.session, span, E0430,
"`self` import can only appear once in an import list");
err.span_label(span, "can only appear once in an import list");
err
}
ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
let mut err = struct_span_err!(resolver.session, span, E0431,
"`self` import can only appear in an import list with \
a non-empty prefix");
err.span_label(span, "can only appear in an import list with a non-empty prefix");
err
}
ResolutionError::FailedToResolve(msg) => {
let mut err = struct_span_err!(resolver.session, span, E0433,
"failed to resolve: {}", msg);
err.span_label(span, msg);
err
}
ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
let mut err = struct_span_err!(resolver.session,
span,
E0434,
"{}",
"can't capture dynamic environment in a fn item");
err.help("use the `|| { ... }` closure form instead");
err
}
ResolutionError::AttemptToUseNonConstantValueInConstant => {
let mut err = struct_span_err!(resolver.session, span, E0435,
"attempt to use a non-constant value in a constant");
err.span_label(span, "non-constant value");
err
}
ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
let shadows_what = binding.descr();
let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
what_binding, shadows_what);
err.span_label(span, format!("cannot be named the same as {} {}",
binding.article(), shadows_what));
let participle = if binding.is_import() { "imported" } else { "defined" };
let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
err.span_label(binding.span, msg);
err
}
ResolutionError::ForwardDeclaredTyParam => {
let mut err = struct_span_err!(resolver.session, span, E0128,
"type parameters with a default cannot use \
forward declared identifiers");
err.span_label(
span, "defaulted type parameters cannot be forward declared".to_string());
err
}
}
}
/// Adjust the impl span so that just the `impl` keyword is taken by removing
/// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
/// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
///
/// Attention: The method used is very fragile since it essentially duplicates the work of the
/// parser. If you need to use this function or something similar, please consider updating the
/// source_map functions and this function to something more robust.
fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
let impl_span = cm.span_until_char(impl_span, '<');
let impl_span = cm.span_until_whitespace(impl_span);
impl_span
}
#[derive(Copy, Clone, Debug)]
struct BindingInfo {
span: Span,
binding_mode: BindingMode,
}
/// Map from the name in a pattern to its binding mode.
type BindingMap = FxHashMap<Ident, BindingInfo>;
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
enum PatternSource {
Match,
IfLet,
WhileLet,
Let,
For,
FnParam,
}
impl PatternSource {
fn descr(self) -> &'static str {
match self {
PatternSource::Match => "match binding",
PatternSource::IfLet => "if let binding",
PatternSource::WhileLet => "while let binding",
PatternSource::Let => "let binding",
PatternSource::For => "for binding",
PatternSource::FnParam => "function parameter",
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
enum AliasPossibility {
No,
Maybe,
}
#[derive(Copy, Clone, Debug)]
enum PathSource<'a> {
// Type paths `Path`.
Type,
// Trait paths in bounds or impls.
Trait(AliasPossibility),
// Expression paths `path`, with optional parent context.
Expr(Option<&'a Expr>),
// Paths in path patterns `Path`.
Pat,
// Paths in struct expressions and patterns `Path { .. }`.
Struct,
// Paths in tuple struct patterns `Path(..)`.
TupleStruct,
// `m::A::B` in `<T as m::A>::B::C`.
TraitItem(Namespace),
// Path in `pub(path)`
Visibility,
}
impl<'a> PathSource<'a> {
fn namespace(self) -> Namespace {
match self {
PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
PathSource::Visibility => TypeNS,
PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
PathSource::TraitItem(ns) => ns,
}
}
fn global_by_default(self) -> bool {
match self {
PathSource::Visibility => true,
PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
PathSource::Struct | PathSource::TupleStruct |
PathSource::Trait(_) | PathSource::TraitItem(..) => false,
}
}
fn defer_to_typeck(self) -> bool {
match self {
PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
PathSource::Struct | PathSource::TupleStruct => true,
PathSource::Trait(_) | PathSource::TraitItem(..) |
PathSource::Visibility => false,
}
}
fn descr_expected(self) -> &'static str {
match self {
PathSource::Type => "type",
PathSource::Trait(_) => "trait",
PathSource::Pat => "unit struct/variant or constant",
PathSource::Struct => "struct, variant or union type",
PathSource::TupleStruct => "tuple struct/variant",
PathSource::Visibility => "module",
PathSource::TraitItem(ns) => match ns {
TypeNS => "associated type",
ValueNS => "method or associated constant",
MacroNS => bug!("associated macro"),
},
PathSource::Expr(parent) => match parent.map(|p| &p.node) {
// "function" here means "anything callable" rather than `Def::Fn`,
// this is not precise but usually more helpful than just "value".
Some(&ExprKind::Call(..)) => "function",
_ => "value",
},
}
}
fn is_expected(self, def: Def) -> bool {
match self {
PathSource::Type => match def {
Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
Def::SelfTy(..) | Def::Existential(..) |
Def::ForeignTy(..) => true,
_ => false,
},
PathSource::Trait(AliasPossibility::No) => match def {
Def::Trait(..) => true,
_ => false,
},
PathSource::Trait(AliasPossibility::Maybe) => match def {
Def::Trait(..) => true,
Def::TraitAlias(..) => true,
_ => false,
},
PathSource::Expr(..) => match def {
Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
Def::SelfCtor(..) => true,
_ => false,
},
PathSource::Pat => match def {
Def::StructCtor(_, CtorKind::Const) |
Def::VariantCtor(_, CtorKind::Const) |
Def::Const(..) | Def::AssociatedConst(..) |
Def::SelfCtor(..) => true,
_ => false,
},
PathSource::TupleStruct => match def {
Def::StructCtor(_, CtorKind::Fn) |
Def::VariantCtor(_, CtorKind::Fn) |
Def::SelfCtor(..) => true,
_ => false,
},
PathSource::Struct => match def {
Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
_ => false,
},
PathSource::TraitItem(ns) => match def {
Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
Def::AssociatedTy(..) if ns == TypeNS => true,
_ => false,
},
PathSource::Visibility => match def {
Def::Mod(..) => true,
_ => false,
},
}
}
fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
__diagnostic_used!(E0404);
__diagnostic_used!(E0405);
__diagnostic_used!(E0412);
__diagnostic_used!(E0422);
__diagnostic_used!(E0423);
__diagnostic_used!(E0425);
__diagnostic_used!(E0531);
__diagnostic_used!(E0532);
__diagnostic_used!(E0573);
__diagnostic_used!(E0574);
__diagnostic_used!(E0575);
__diagnostic_used!(E0576);
__diagnostic_used!(E0577);
__diagnostic_used!(E0578);
match (self, has_unexpected_resolution) {
(PathSource::Trait(_), true) => "E0404",
(PathSource::Trait(_), false) => "E0405",
(PathSource::Type, true) => "E0573",
(PathSource::Type, false) => "E0412",
(PathSource::Struct, true) => "E0574",
(PathSource::Struct, false) => "E0422",
(PathSource::Expr(..), true) => "E0423",
(PathSource::Expr(..), false) => "E0425",
(PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
(PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
(PathSource::TraitItem(..), true) => "E0575",
(PathSource::TraitItem(..), false) => "E0576",
(PathSource::Visibility, true) => "E0577",
(PathSource::Visibility, false) => "E0578",
}
}
}
// A minimal representation of a path segment. We use this in resolve because
// we synthesize 'path segments' which don't have the rest of an AST or HIR
// PathSegment.
#[derive(Clone, Copy, Debug)]
pub struct Segment {
ident: Ident,
id: Option<NodeId>,
}
impl Segment {
fn from_path(path: &Path) -> Vec<Segment> {
path.segments.iter().map(|s| s.into()).collect()
}
fn from_ident(ident: Ident) -> Segment {
Segment {
ident,
id: None,
}
}
fn names_to_string(segments: &[Segment]) -> String {
names_to_string(&segments.iter()
.map(|seg| seg.ident)
.collect::<Vec<_>>())
}
}
impl<'a> From<&'a ast::PathSegment> for Segment {
fn from(seg: &'a ast::PathSegment) -> Segment {
Segment {
ident: seg.ident,
id: Some(seg.id),
}
}
}
struct UsePlacementFinder {
target_module: NodeId,
span: Option<Span>,
found_use: bool,
}
impl UsePlacementFinder {
fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
let mut finder = UsePlacementFinder {
target_module,
span: None,
found_use: false,
};
visit::walk_crate(&mut finder, krate);
(finder.span, finder.found_use)
}
}
impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
fn visit_mod(
&mut self,
module: &'tcx ast::Mod,
_: Span,
_: &[ast::Attribute],
node_id: NodeId,
) {
if self.span.is_some() {
return;
}
if node_id != self.target_module {
visit::walk_mod(self, module);
return;
}
// find a use statement
for item in &module.items {
match item.node {
ItemKind::Use(..) => {
// don't suggest placing a use before the prelude
// import or other generated ones
if item.span.ctxt().outer().expn_info().is_none() {
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.ctxt().outer().expn_info().is_none() {
// 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());
}
}
}
}
},
}
}
}
}
/// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
fn visit_item(&mut self, item: &'tcx Item) {
self.resolve_item(item);
}
fn visit_arm(&mut self, arm: &'tcx Arm) {
self.resolve_arm(arm);
}
fn visit_block(&mut self, block: &'tcx Block) {
self.resolve_block(block);
}
fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
self.with_constant_rib(|this| {
visit::walk_anon_const(this, constant);
});
}
fn visit_expr(&mut self, expr: &'tcx Expr) {
self.resolve_expr(expr, None);
}
fn visit_local(&mut self, local: &'tcx Local) {
self.resolve_local(local);
}
fn visit_ty(&mut self, ty: &'tcx Ty) {
match ty.node {
TyKind::Path(ref qself, ref path) => {
self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
}
TyKind::ImplicitSelf => {
let self_ty = keywords::SelfType.ident();
let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
.map_or(Def::Err, |d| d.def());
self.record_def(ty.id, PathResolution::new(def));
}
_ => (),
}
visit::walk_ty(self, ty);
}
fn visit_poly_trait_ref(&mut self,
tref: &'tcx ast::PolyTraitRef,
m: &'tcx ast::TraitBoundModifier) {
self.smart_resolve_path(tref.trait_ref.ref_id, None,
&tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
visit::walk_poly_trait_ref(self, tref, m);
}
fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
let type_parameters = match foreign_item.node {
ForeignItemKind::Fn(_, ref generics) => {
HasTypeParameters(generics, ItemRibKind)
}
ForeignItemKind::Static(..) => NoTypeParameters,
ForeignItemKind::Ty => NoTypeParameters,
ForeignItemKind::Macro(..) => NoTypeParameters,
};
self.with_type_parameter_rib(type_parameters, |this| {
visit::walk_foreign_item(this, foreign_item);
});
}
fn visit_fn(&mut self,
function_kind: FnKind<'tcx>,
declaration: &'tcx FnDecl,
_: Span,
node_id: NodeId)
{
let (rib_kind, asyncness) = match function_kind {
FnKind::ItemFn(_, ref header, ..) =>
(ItemRibKind, header.asyncness),
FnKind::Method(_, ref sig, _, _) =>
(TraitOrImplItemRibKind, sig.header.asyncness),
FnKind::Closure(_) =>
// Async closures aren't resolved through `visit_fn`-- they're
// processed separately
(ClosureRibKind(node_id), IsAsync::NotAsync),
};
// Create a value rib for the function.
self.ribs[ValueNS].push(Rib::new(rib_kind));
// Create a label rib for the function.
self.label_ribs.push(Rib::new(rib_kind));
// Add each argument to the rib.
let mut bindings_list = FxHashMap::default();
for argument in &declaration.inputs {
self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
self.visit_ty(&argument.ty);
debug!("(resolving function) recorded argument");
}
visit::walk_fn_ret_ty(self, &declaration.output);
// Resolve the function body, potentially inside the body of an async closure
if let IsAsync::Async { closure_id, .. } = asyncness {
let rib_kind = ClosureRibKind(closure_id);
self.ribs[ValueNS].push(Rib::new(rib_kind));
self.label_ribs.push(Rib::new(rib_kind));
}
match function_kind {
FnKind::ItemFn(.., body) |
FnKind::Method(.., body) => {
self.visit_block(body);
}
FnKind::Closure(body) => {
self.visit_expr(body);
}
};
// Leave the body of the async closure
if asyncness.is_async() {
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
debug!("(resolving function) leaving function");
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
fn visit_generics(&mut self, generics: &'tcx Generics) {
// For type parameter defaults, we have to ban access
// to following type parameters, as the Substs can only
// provide previous type parameters as they're built. We
// put all the parameters on the ban list and then remove
// them one by one as they are processed and become available.
let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
let mut found_default = false;
default_ban_rib.bindings.extend(generics.params.iter()
.filter_map(|param| match param.kind {
GenericParamKind::Lifetime { .. } => None,
GenericParamKind::Type { ref default, .. } => {
found_default |= default.is_some();
if found_default {
Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
} else {
None
}
}
}));
for param in &generics.params {
match param.kind {
GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
GenericParamKind::Type { ref default, .. } => {
for bound in &param.bounds {
self.visit_param_bound(bound);
}
if let Some(ref ty) = default {
self.ribs[TypeNS].push(default_ban_rib);
self.visit_ty(ty);
default_ban_rib = self.ribs[TypeNS].pop().unwrap();
}
// Allow all following defaults to refer to this type parameter.
default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
}
}
}
for p in &generics.where_clause.predicates {
self.visit_where_predicate(p);
}
}
}
#[derive(Copy, Clone)]
enum TypeParameters<'a, 'b> {
NoTypeParameters,
HasTypeParameters(// Type parameters.
&'b Generics,
// The kind of the rib used for type parameters.
RibKind<'a>),
}
/// The rib kind controls the translation of local
/// definitions (`Def::Local`) to upvars (`Def::Upvar`).
#[derive(Copy, Clone, Debug)]
enum RibKind<'a> {
/// No translation needs to be applied.
NormalRibKind,
/// We passed through a closure scope at the given node ID.
/// Translate upvars as appropriate.
ClosureRibKind(NodeId /* func id */),
/// We passed through an impl or trait and are now in one of its
/// methods or associated types. Allow references to ty params that impl or trait
/// binds. Disallow any other upvars (including other ty params that are
/// upvars).
TraitOrImplItemRibKind,
/// We passed through an item scope. Disallow upvars.
ItemRibKind,
/// We're in a constant item. Can't refer to dynamic stuff.
ConstantItemRibKind,
/// We passed through a module.
ModuleRibKind(Module<'a>),
/// We passed through a `macro_rules!` statement
MacroDefinition(DefId),
/// All bindings in this rib are type parameters that can't be used
/// from the default of a type parameter because they're not declared
/// before said type parameter. Also see the `visit_generics` override.
ForwardTyParamBanRibKind,
}
/// One local scope.
///
/// A rib represents a scope names can live in. Note that these appear in many places, not just
/// around braces. At any place where the list of accessible names (of the given namespace)
/// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
/// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
/// etc.
///
/// Different [rib kinds](enum.RibKind) are transparent for different names.
///
/// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
/// resolving, the name is looked up from inside out.
#[derive(Debug)]
struct Rib<'a> {
bindings: FxHashMap<Ident, Def>,
kind: RibKind<'a>,
}
impl<'a> Rib<'a> {
fn new(kind: RibKind<'a>) -> Rib<'a> {
Rib {
bindings: Default::default(),
kind,
}
}
}
/// An intermediate resolution result.
///
/// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
/// items are visible in their whole block, while defs only from the place they are defined
/// forward.
enum LexicalScopeBinding<'a> {
Item(&'a NameBinding<'a>),
Def(Def),
}
impl<'a> LexicalScopeBinding<'a> {
fn item(self) -> Option<&'a NameBinding<'a>> {
match self {
LexicalScopeBinding::Item(binding) => Some(binding),
_ => None,
}
}
fn def(self) -> Def {
match self {
LexicalScopeBinding::Item(binding) => binding.def(),
LexicalScopeBinding::Def(def) => def,
}
}
}
#[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 or `extern::`.
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() == rhs.def(),
(ModuleOrUniformRoot::CrateRootAndExternPrelude,
ModuleOrUniformRoot::CrateRootAndExternPrelude) |
(ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
(ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
_ => false,
}
}
}
#[derive(Clone, Debug)]
enum PathResult<'a> {
Module(ModuleOrUniformRoot<'a>),
NonModule(PathResolution),
Indeterminate,
Failed(Span, String, bool /* is the error from the last segment? */),
}
enum ModuleKind {
/// An anonymous module, eg. 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(Def, Name),
}
/// 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,
resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
Option<&'a NameBinding<'a>>)>>,
multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
Option<Def>)>>,
builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
// Macro invocations that can expand into items in this module.
unresolved_invocations: RefCell<FxHashSet<Mark>>,
no_implicit_prelude: bool,
glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
globs: RefCell<Vec<&'a ImportDirective<'a>>>,
// Used to memoize the traits in this module for faster searches through all traits in scope.
traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
// Whether this module is populated. If not populated, any attempt to
// access the children must be preceded with a
// `populate_module_if_necessary` call.
populated: Cell<bool>,
/// Span of the module itself. Used for error reporting.
span: Span,
expansion: Mark,
}
type Module<'a> = &'a ModuleData<'a>;
impl<'a> ModuleData<'a> {
fn new(parent: Option<Module<'a>>,
kind: ModuleKind,
normal_ancestor_id: DefId,
expansion: Mark,
span: Span) -> Self {
ModuleData {
parent,
kind,
normal_ancestor_id,
resolutions: Default::default(),
single_segment_macro_resolutions: RefCell::new(Vec::new()),
multi_segment_macro_resolutions: RefCell::new(Vec::new()),
builtin_attrs: RefCell::new(Vec::new()),
unresolved_invocations: Default::default(),
no_implicit_prelude: false,
glob_importers: RefCell::new(Vec::new()),
globs: RefCell::new(Vec::new()),
traits: RefCell::new(None),
populated: Cell::new(normal_ancestor_id.is_local()),
span,
expansion,
}
}
fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
}
}
fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
let resolutions = self.resolutions.borrow();
let mut resolutions = resolutions.iter().collect::<Vec<_>>();
resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
for &(&(ident, ns), &resolution) in resolutions.iter() {
resolution.borrow().binding.map(|binding| f(ident, ns, binding));
}
}
fn def(&self) -> Option<Def> {
match self.kind {
ModuleKind::Def(def, _) => Some(def),
_ => None,
}
}
fn def_id(&self) -> Option<DefId> {
self.def().as_ref().map(Def::def_id)
}
// `self` resolves to the first module ancestor that `is_normal`.
fn is_normal(&self) -> bool {
match self.kind {
ModuleKind::Def(Def::Mod(_), _) => true,
_ => false,
}
}
fn is_trait(&self) -> bool {
match self.kind {
ModuleKind::Def(Def::Trait(_), _) => true,
_ => false,
}
}
fn is_local(&self) -> bool {
self.normal_ancestor_id.is_local()
}
fn nearest_item_scope(&'a self) -> Module<'a> {
if self.is_trait() { self.parent.unwrap() } else { 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.def())
}
}
/// Records a possibly-private value, type, or module definition.
#[derive(Clone, Debug)]
pub struct NameBinding<'a> {
kind: NameBindingKind<'a>,
expansion: Mark,
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> {
Def(Def, /* is_macro_export */ bool),
Module(Module<'a>),
Import {
binding: &'a NameBinding<'a>,
directive: &'a ImportDirective<'a>,
used: Cell<bool>,
},
Ambiguity {
kind: AmbiguityKind,
b1: &'a NameBinding<'a>,
b2: &'a NameBinding<'a>,
}
}
struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
struct UseError<'a> {
err: DiagnosticBuilder<'a>,
/// Attach `use` statements for these candidates
candidates: Vec<ImportSuggestion>,
/// The node id of the module to place the use statements in
node_id: NodeId,
/// Whether the diagnostic should state that it's "better"
better: bool,
}
#[derive(Clone, Copy, PartialEq, Debug)]
enum AmbiguityKind {
Import,
AbsolutePath,
BuiltinAttr,
DeriveHelper,
LegacyHelperVsPrelude,
LegacyVsModern,
GlobVsOuter,
GlobVsGlob,
GlobVsExpanded,
MoreExpandedVsOuter,
}
impl AmbiguityKind {
fn descr(self) -> &'static str {
match self {
AmbiguityKind::Import =>
"name vs any other name during import resolution",
AmbiguityKind::AbsolutePath =>
"name in the crate root vs extern crate during absolute path resolution",
AmbiguityKind::BuiltinAttr =>
"built-in attribute vs any other name",
AmbiguityKind::DeriveHelper =>
"derive helper attribute vs any other name",
AmbiguityKind::LegacyHelperVsPrelude =>
"legacy plugin helper attribute vs name from prelude",
AmbiguityKind::LegacyVsModern =>
"`macro_rules` vs non-`macro_rules` from other module",
AmbiguityKind::GlobVsOuter =>
"glob import vs any other name from outer scope during import/macro resolution",
AmbiguityKind::GlobVsGlob =>
"glob import vs glob import in the same module",
AmbiguityKind::GlobVsExpanded =>
"glob import vs macro-expanded name in the same \
module during import/macro resolution",
AmbiguityKind::MoreExpandedVsOuter =>
"macro-expanded name vs less macro-expanded name \
from outer scope during import/macro resolution",
}
}
}
/// Miscellaneous bits of metadata for better ambiguity error reporting.
#[derive(Clone, Copy, PartialEq)]
enum AmbiguityErrorMisc {
SuggestCrate,
SuggestSelf,
FromPrelude,
None,
}
struct AmbiguityError<'a> {
kind: AmbiguityKind,
ident: Ident,
b1: &'a NameBinding<'a>,
b2: &'a NameBinding<'a>,
misc1: AmbiguityErrorMisc,
misc2: AmbiguityErrorMisc,
}
impl<'a> NameBinding<'a> {
fn module(&self) -> Option<Module<'a>> {
match self.kind {
NameBindingKind::Module(module) => Some(module),
NameBindingKind::Import { binding, .. } => binding.module(),
_ => None,
}
}
fn def(&self) -> Def {
match self.kind {
NameBindingKind::Def(def, _) => def,
NameBindingKind::Module(module) => module.def().unwrap(),
NameBindingKind::Import { binding, .. } => binding.def(),
NameBindingKind::Ambiguity { .. } => Def::Err,
}
}
fn def_ignoring_ambiguity(&self) -> Def {
match self.kind {
NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
_ => self.def(),
}
}
// We sometimes need to treat variants as `pub` for backwards compatibility
fn pseudo_vis(&self) -> ty::Visibility {
if self.is_variant() && self.def().def_id().is_local() {
ty::Visibility::Public
} else {
self.vis
}
}
fn is_variant(&self) -> bool {
match self.kind {
NameBindingKind::Def(Def::Variant(..), _) |
NameBindingKind::Def(Def::VariantCtor(..), _) => true,
_ => false,
}
}
fn is_extern_crate(&self) -> bool {
match self.kind {
NameBindingKind::Import {
directive: &ImportDirective {
subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
}, ..
} => true,
NameBindingKind::Module(
&ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
) => def_id.index == CRATE_DEF_INDEX,
_ => false,
}
}
fn is_import(&self) -> bool {
match self.kind {
NameBindingKind::Import { .. } => true,
_ => false,
}
}
fn is_glob_import(&self) -> bool {
match self.kind {
NameBindingKind::Import { directive, .. } => directive.is_glob(),
NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
_ => false,
}
}
fn is_importable(&self) -> bool {
match self.def() {
Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
_ => true,
}
}
fn is_macro_def(&self) -> bool {
match self.kind {
NameBindingKind::Def(Def::Macro(..), _) => true,
_ => false,
}
}
fn macro_kind(&self) -> Option<MacroKind> {
match self.def_ignoring_ambiguity() {
Def::Macro(_, kind) => Some(kind),
Def::NonMacroAttr(..) => Some(MacroKind::Attr),
_ => None,
}
}
fn descr(&self) -> &'static str {
if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
}
fn article(&self) -> &'static str {
if self.is_extern_crate() { "an" } else { self.def().article() }
}
// 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: Mark, 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.
#[derive(Default)]
struct PrimitiveTypeTable {
primitive_types: FxHashMap<Name, PrimTy>,
}
impl PrimitiveTypeTable {
fn new() -> PrimitiveTypeTable {
let mut table = PrimitiveTypeTable::default();
table.intern("bool", Bool);
table.intern("char", Char);
table.intern("f32", Float(FloatTy::F32));
table.intern("f64", Float(FloatTy::F64));
table.intern("isize", Int(IntTy::Isize));
table.intern("i8", Int(IntTy::I8));
table.intern("i16", Int(IntTy::I16));
table.intern("i32", Int(IntTy::I32));
table.intern("i64", Int(IntTy::I64));
table.intern("i128", Int(IntTy::I128));
table.intern("str", Str);
table.intern("usize", Uint(UintTy::Usize));
table.intern("u8", Uint(UintTy::U8));
table.intern("u16", Uint(UintTy::U16));
table.intern("u32", Uint(UintTy::U32));
table.intern("u64", Uint(UintTy::U64));
table.intern("u128", Uint(UintTy::U128));
table
}
fn intern(&mut self, string: &str, primitive_type: PrimTy) {
self.primitive_types.insert(Symbol::intern(string), primitive_type);
}
}
#[derive(Default, Clone)]
pub struct ExternPreludeEntry<'a> {
extern_crate_item: Option<&'a NameBinding<'a>>,
pub introduced_by_item: bool,
}
/// The main resolver class.
///
/// This is the visitor that walks the whole crate.
pub struct Resolver<'a, 'b: 'a> {
session: &'a Session,
cstore: &'a CStore,
pub definitions: Definitions,
graph_root: Module<'a>,
prelude: Option<Module<'a>>,
pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
/// n.b. This is used only for better diagnostics, not name resolution itself.
has_self: FxHashSet<DefId>,
/// Names of fields of an item `DefId` accessible with dot syntax.
/// Used for hints during error reporting.
field_names: FxHashMap<DefId, Vec<Name>>,
/// All imports known to succeed or fail.
determined_imports: Vec<&'a ImportDirective<'a>>,
/// All non-determined imports.
indeterminate_imports: Vec<&'a ImportDirective<'a>>,
/// The module that represents the current item scope.
current_module: Module<'a>,
/// The current set of local scopes for types and values.
/// FIXME #4948: Reuse ribs to avoid allocation.
ribs: PerNS<Vec<Rib<'a>>>,
/// The current set of local scopes, for labels.
label_ribs: Vec<Rib<'a>>,
/// The trait that the current context can refer to.
current_trait_ref: Option<(Module<'a>, TraitRef)>,
/// The current self type if inside an impl (used for better errors).
current_self_type: Option<Ty>,
/// The current self item if inside an ADT (used for better errors).
current_self_item: Option<NodeId>,
/// FIXME: Refactor things so that this is passed through arguments and not resolver.
last_import_segment: bool,
blacklisted_binding: Option<&'a NameBinding<'a>>,
/// The idents for the primitive types.
primitive_type_table: PrimitiveTypeTable,
def_map: DefMap,
import_map: ImportMap,
pub freevars: FreevarMap,
freevars_seen: NodeMap<NodeMap<usize>>,
pub export_map: ExportMap,
pub trait_map: TraitMap,
/// A map from nodes to anonymous modules.
/// Anonymous modules are pseudo-modules that are implicitly created around items
/// contained within blocks.
///
/// For example, if we have this:
///
/// fn f() {
/// fn g() {
/// ...
/// }
/// }
///
/// There will be an anonymous module created around `g` with the ID of the
/// entry block for `f`.
block_map: NodeMap<Module<'a>>,
module_map: FxHashMap<DefId, Module<'a>>,
extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
pub make_glob_map: bool,
/// Maps imports to the names of items actually imported (this actually maps
/// all imports, but only glob imports are actually interesting).
pub glob_map: GlobMap,
used_imports: FxHashSet<(NodeId, Namespace)>,
pub maybe_unused_trait_imports: NodeSet,
pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
/// A list of labels as of yet unused. Labels will be removed from this map when
/// they are used (in a `break` or `continue` statement)
pub unused_labels: FxHashMap<NodeId, Span>,
/// privacy errors are delayed until the end in order to deduplicate them
privacy_errors: Vec<PrivacyError<'a>>,
/// ambiguity errors are delayed for deduplication
ambiguity_errors: Vec<AmbiguityError<'a>>,
/// `use` injections are delayed for better placement and deduplication
use_injections: Vec<UseError<'a>>,
/// crate-local macro expanded `macro_export` referred to by a module-relative path
macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
arenas: &'a ResolverArenas<'a>,
dummy_binding: &'a NameBinding<'a>,
crate_loader: &'a mut CrateLoader<'b>,
macro_names: FxHashSet<Ident>,
builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
pub all_macros: FxHashMap<Name, Def>,
macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
macro_defs: FxHashMap<Mark, DefId>,
local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
pub whitelisted_legacy_custom_derives: Vec<Name>,
pub found_unresolved_macro: bool,
/// List of crate local macros that we need to warn about as being unused.
/// Right now this only includes macro_rules! macros, and macros 2.0.
unused_macros: FxHashSet<DefId>,
/// Maps the `Mark` of an expansion to its containing module or block.
invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
/// Avoid duplicated errors for "name already defined".
name_already_seen: FxHashMap<Name, Span>,
potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
/// This table maps struct IDs into struct constructor IDs,
/// it's not used during normal resolution, only for better error reporting.
struct_constructors: DefIdMap<(Def, ty::Visibility)>,
/// Only used for better errors on `fn(): fn()`
current_type_ascription: Vec<Span>,
injected_crate: Option<Module<'a>>,
}
/// Nothing really interesting here, it just provides memory for the rest of the crate.
#[derive(Default)]
pub struct ResolverArenas<'a> {
modules: arena::TypedArena<ModuleData<'a>>,
local_modules: RefCell<Vec<Module<'a>>>,
name_bindings: arena::TypedArena<NameBinding<'a>>,
import_directives: arena::TypedArena<ImportDirective<'a>>,
name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
invocation_data: arena::TypedArena<InvocationData<'a>>,
legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
}
impl<'a> ResolverArenas<'a> {
fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
let module = self.modules.alloc(module);
if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
self.local_modules.borrow_mut().push(module);
}
module
}
fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
self.local_modules.borrow()
}
fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
self.name_bindings.alloc(name_binding)
}
fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
-> &'a ImportDirective {
self.import_directives.alloc(import_directive)
}
fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
self.name_resolutions.alloc(Default::default())
}
fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
-> &'a InvocationData<'a> {
self.invocation_data.alloc(expansion_data)
}
fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
self.legacy_bindings.alloc(binding)
}
}
impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
fn parent(self, id: DefId) -> Option<DefId> {
match id.krate {
LOCAL_CRATE => self.definitions.def_key(id.index).parent,
_ => self.cstore.def_key(id).parent,
}.map(|index| DefId { index, ..id })
}
}
/// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
/// the resolver is no longer needed as all the relevant information is inline.
impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
fn resolve_hir_path(
&mut self,
path: &ast::Path,
is_value: bool,
) -> hir::Path {
self.resolve_hir_path_cb(path, is_value,
|resolver, span, error| resolve_error(resolver, span, error))
}
fn resolve_str_path(
&mut self,
span: Span,
crate_root: Option<&str>,
components: &[&str],
is_value: bool
) -> hir::Path {
let segments = iter::once(keywords::CrateRoot.ident())
.chain(
crate_root.into_iter()
.chain(components.iter().cloned())
.map(Ident::from_str)
).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
let path = ast::Path {
span,
segments,
};
self.resolve_hir_path(&path, is_value)
}
fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
self.def_map.get(&id).cloned()
}
fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
self.import_map.get(&id).cloned().unwrap_or_default()
}
fn definitions(&mut self) -> &mut Definitions {
&mut self.definitions
}
}
impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
/// 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.
pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
-> Result<hir::Path, ()> {
use std::iter;
let mut errored = false;
let path = if path_str.starts_with("::") {
ast::Path {
span,
segments: iter::once(keywords::CrateRoot.ident())
.chain({
path_str.split("::").skip(1).map(Ident::from_str)
})
.map(|i| self.new_ast_path_segment(i))
.collect(),
}
} else {
ast::Path {
span,
segments: path_str
.split("::")
.map(Ident::from_str)
.map(|i| self.new_ast_path_segment(i))
.collect(),
}
};
let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
if errored || path.def == Def::Err {
Err(())
} else {
Ok(path)
}
}
/// resolve_hir_path, but takes a callback in case there was an error
fn resolve_hir_path_cb<F>(
&mut self,
path: &ast::Path,
is_value: bool,
error_callback: F,
) -> hir::Path
where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
{
let namespace = if is_value { ValueNS } else { TypeNS };
let span = path.span;
let segments = &path.segments;
let path = Segment::from_path(&path);
// FIXME (Manishearth): Intra doc links won't get warned of epoch changes
let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
span, CrateLint::No) {
PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
module.def().unwrap(),
PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
path_res.base_def(),
PathResult::NonModule(..) => {
let msg = "type-relative paths are not supported in this context";
error_callback(self, span, ResolutionError::FailedToResolve(msg));
Def::Err
}
PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
PathResult::Failed(span, msg, _) => {
error_callback(self, span, ResolutionError::FailedToResolve(&msg));
Def::Err
}
};
let segments: Vec<_> = segments.iter().map(|seg| {
let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
hir_seg
}).collect();
hir::Path {
span,
def,
segments: segments.into(),
}
}
fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
let mut seg = ast::PathSegment::from_ident(ident);
seg.id = self.session.next_node_id();
seg
}
}
impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
pub fn new(session: &'a Session,
cstore: &'a CStore,
krate: &Crate,
crate_name: &str,
make_glob_map: MakeGlobMap,
crate_loader: &'a mut CrateLoader<'crateloader>,
arenas: &'a ResolverArenas<'a>)
-> Resolver<'a, 'crateloader> {
let root_def_id = DefId::local(CRATE_DEF_INDEX);
let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
let graph_root = arenas.alloc_module(ModuleData {
no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
});
let mut module_map = FxHashMap::default();
module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
let mut definitions = Definitions::new();
DefCollector::new(&mut definitions, Mark::root())
.collect_root(crate_name, session.local_crate_disambiguator());
let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
.collect();
if !attr::contains_name(&krate.attrs, "no_core") {
extern_prelude.insert(Ident::from_str("core"), Default::default());
if !attr::contains_name(&krate.attrs, "no_std") {
extern_prelude.insert(Ident::from_str("std"), Default::default());
if session.rust_2018() {
extern_prelude.insert(Ident::from_str("meta"), Default::default());
}
}
}
let mut invocations = FxHashMap::default();
invocations.insert(Mark::root(),
arenas.alloc_invocation_data(InvocationData::root(graph_root)));
let mut macro_defs = FxHashMap::default();
macro_defs.insert(Mark::root(), root_def_id);
Resolver {
session,
cstore,
definitions,
// The outermost module has def ID 0; this is not reflected in the
// AST.
graph_root,
prelude: None,
extern_prelude,
has_self: FxHashSet::default(),
field_names: FxHashMap::default(),
determined_imports: Vec::new(),
indeterminate_imports: Vec::new(),
current_module: graph_root,
ribs: PerNS {
value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
},
label_ribs: Vec::new(),
current_trait_ref: None,
current_self_type: None,
current_self_item: None,
last_import_segment: false,
blacklisted_binding: None,
primitive_type_table: PrimitiveTypeTable::new(),
def_map: Default::default(),
import_map: Default::default(),
freevars: Default::default(),
freevars_seen: Default::default(),
export_map: FxHashMap::default(),
trait_map: Default::default(),
module_map,
block_map: Default::default(),
extern_module_map: FxHashMap::default(),
binding_parent_modules: FxHashMap::default(),
make_glob_map: make_glob_map == MakeGlobMap::Yes,
glob_map: Default::default(),
used_imports: FxHashSet::default(),
maybe_unused_trait_imports: Default::default(),
maybe_unused_extern_crates: Vec::new(),
unused_labels: FxHashMap::default(),
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::Def(Def::Err, false),
expansion: Mark::root(),
span: DUMMY_SP,
vis: ty::Visibility::Public,
}),
crate_loader,
macro_names: FxHashSet::default(),
builtin_macros: FxHashMap::default(),
macro_use_prelude: FxHashMap::default(),
all_macros: FxHashMap::default(),
macro_map: FxHashMap::default(),
invocations,
macro_defs,
local_macro_def_scopes: FxHashMap::default(),
name_already_seen: FxHashMap::default(),
whitelisted_legacy_custom_derives: Vec::new(),
potentially_unused_imports: Vec::new(),
struct_constructors: Default::default(),
found_unresolved_macro: false,
unused_macros: FxHashSet::default(),
current_type_ascription: Vec::new(),
injected_crate: None,
}
}
pub fn arenas() -> ResolverArenas<'a> {
Default::default()
}
/// 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 macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
loop {
match self.macro_defs.get(&ctxt.outer()) {
Some(&def_id) => return def_id,
None => ctxt.remove_mark(),
};
}
}
/// Entry point to crate resolution.
pub fn resolve_crate(&mut self, krate: &Crate) {
ImportResolver { resolver: self }.finalize_imports();
self.current_module = self.graph_root;
self.finalize_current_module_macro_resolutions();
visit::walk_crate(self, krate);
check_unused::check_crate(self, krate);
self.report_errors(krate);
self.crate_loader.postprocess(krate);
}
fn new_module(
&self,
parent: Module<'a>,
kind: ModuleKind,
normal_ancestor_id: DefId,
expansion: Mark,
span: Span,
) -> Module<'a> {
let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
self.arenas.alloc_module(module)
}
fn record_use(&mut self, ident: Ident, ns: Namespace,
used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
match used_binding.kind {
NameBindingKind::Import { directive, binding, ref used } if !used.get() => {
// Avoid marking `extern crate` items that refer to a name from extern prelude,
// but not introduce it, as used if they are accessed from lexical scope.
if is_lexical_scope {
if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
if let Some(crate_item) = entry.extern_crate_item {
if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
return;
}
}
}
}
used.set(true);
directive.used.set(true);
self.used_imports.insert((directive.id, ns));
self.add_to_glob_map(directive.id, ident);
self.record_use(ident, ns, binding, false);
}
NameBindingKind::Ambiguity { kind, b1, b2 } => {
self.ambiguity_errors.push(AmbiguityError {
kind, ident, b1, b2,
misc1: AmbiguityErrorMisc::None,
misc2: AmbiguityErrorMisc::None,
});
}
_ => {}
}
}
fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
if self.make_glob_map {
self.glob_map.entry(id).or_default().insert(ident.name);
}
}
/// 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,
record_used_id: Option<NodeId>,
path_span: Span)
-> Option<LexicalScopeBinding<'a>> {
let record_used = record_used_id.is_some();
assert!(ns == TypeNS || ns == ValueNS);
if ns == TypeNS {
ident.span = if ident.name == keywords::SelfType.name() {
// FIXME(jseyfried) improve `Self` hygiene
ident.span.with_ctxt(SyntaxContext::empty())
} else {
ident.span.modern()
}
} else {
ident = ident.modern_and_legacy();
}
// Walk backwards up the ribs in scope.
let mut module = self.graph_root;
for i in (0 .. self.ribs[ns].len()).rev() {
if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
// The ident resolves to a type parameter or local variable.
return Some(LexicalScopeBinding::Def(
self.adjust_local_def(ns, i, def, record_used, path_span)
));
}
module = match self.ribs[ns][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,
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.span = ident.span.modern();
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 orig_current_module = self.current_module;
self.current_module = module; // Lexical resolutions can never be a privacy error.
let result = self.resolve_ident_in_module_unadjusted(
ModuleOrUniformRoot::Module(module),
ident,
ns,
record_used,
path_span,
);
self.current_module = orig_current_module;
match result {
Ok(binding) => {
if let Some(node_id) = poisoned {
self.session.buffer_lint_with_diagnostic(
lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
node_id, ident.span,
&format!("cannot find {} `{}` in this scope", ns.descr(), ident),
lint::builtin::BuiltinLintDiagnostics::
ProcMacroDeriveResolutionFallback(ident.span),
);
}
return Some(LexicalScopeBinding::Item(binding))
}
Err(Determined) => continue,
Err(Undetermined) =>
span_bug!(ident.span, "undetermined resolution during main resolution pass"),
}
}
if !module.no_implicit_prelude {
if ns == TypeNS {
if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
return Some(LexicalScopeBinding::Item(binding));
}
}
if ns == TypeNS && is_known_tool(ident.name) {
let binding = (Def::ToolMod, ty::Visibility::Public,
DUMMY_SP, Mark::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,
false,
path_span,
) {
return Some(LexicalScopeBinding::Item(binding));
}
}
}
None
}
fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
-> Option<Module<'a>> {
if !module.expansion.is_descendant_of(span.ctxt().outer()) {
return Some(self.macro_def_scope(span.remove_mark()));
}
if let ModuleKind::Block(..) = module.kind {
return Some(module.parent.unwrap());
}
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 module.expansion.looks_like_proc_macro_derive() {
if parent.expansion.is_descendant_of(span.ctxt().outer()) {
*poisoned = Some(node_id);
return module.parent;
}
}
}
}
None
}
fn resolve_ident_in_module(
&mut self,
module: ModuleOrUniformRoot<'a>,
ident: Ident,
ns: Namespace,
parent_scope: Option<&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: Option<&ParentScope<'a>>,
record_used: bool,
path_span: Span
) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
let orig_current_module = self.current_module;
match module {
ModuleOrUniformRoot::Module(module) => {
ident.span = ident.span.modern();
if let Some(def) = ident.span.adjust(module.expansion) {
self.current_module = self.macro_def_scope(def);
}
}
ModuleOrUniformRoot::ExternPrelude => {
ident.span = ident.span.modern();
ident.span.adjust(Mark::root());
}
ModuleOrUniformRoot::CrateRootAndExternPrelude |
ModuleOrUniformRoot::CurrentScope => {
// No adjustments
}
}
let result = self.resolve_ident_in_module_unadjusted_ext(
module, ident, ns, parent_scope, false, record_used, path_span,
);
self.current_module = orig_current_module;
result
}
fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
let mut ctxt = ident.span.ctxt();
let mark = if ident.name == keywords::DollarCrate.name() {
// When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
// we don't want to pretend that the `macro_rules!` definition is in the `macro`
// as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
// FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
// definitions actually produced by `macro` and `macro` definitions produced by
// `macro_rules!`, but at least such configurations are not stable yet.
ctxt = ctxt.modern_and_legacy();
let mut iter = ctxt.marks().into_iter().rev().peekable();
let mut result = None;
// Find the last modern mark from the end if it exists.
while let Some(&(mark, transparency)) = iter.peek() {
if transparency == Transparency::Opaque {
result = Some(mark);
iter.next();
} else {
break;
}
}
// Then find the last legacy mark from the end if it exists.
for (mark, transparency) in iter {
if transparency == Transparency::SemiTransparent {
result = Some(mark);
} else {
break;
}
}
result
} else {
ctxt = ctxt.modern();
ctxt.adjust(Mark::root())
};
let module = match mark {
Some(def) => self.macro_def_scope(def),
None => return self.graph_root,
};
self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
}
fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
let mut module = self.get_module(module.normal_ancestor_id);
while module.span.ctxt().modern() != *ctxt {
let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
module = self.get_module(parent.normal_ancestor_id);
}
module
}
// AST resolution
//
// We maintain a list of value ribs and type ribs.
//
// Simultaneously, we keep track of the current position in the module
// graph in the `current_module` pointer. When we go to resolve a name in
// the value or type namespaces, we first look through all the ribs and
// then query the module graph. When we resolve a name in the module
// namespace, we can skip all the ribs (since nested modules are not
// allowed within blocks in Rust) and jump straight to the current module
// graph node.
//
// Named implementations are handled separately. When we find a method
// call, we consult the module node to find all of the implementations in
// scope. This information is lazily cached in the module node. We then
// generate a fake "implementation scope" containing all the
// implementations thus found, for compatibility with old resolve pass.
pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
where F: FnOnce(&mut Resolver) -> T
{
let id = self.definitions.local_def_id(id);
let module = self.module_map.get(&id).cloned(); // clones a reference
if let Some(module) = module {
// Move down in the graph.
let orig_module = replace(&mut self.current_module, module);
self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
self.finalize_current_module_macro_resolutions();
let ret = f(self);
self.current_module = orig_module;
self.ribs[ValueNS].pop();
self.ribs[TypeNS].pop();
ret
} else {
f(self)
}
}
/// Searches the current set of local scopes for labels. Returns the first non-None label that
/// is returned by the given predicate function
///
/// Stops after meeting a closure.
fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
where P: Fn(&Rib, Ident) -> Option<R>
{
for rib in self.label_ribs.iter().rev() {
match rib.kind {
NormalRibKind => {}
// If an invocation of this macro created `ident`, give up on `ident`
// and switch to `ident`'s source from the macro definition.
MacroDefinition(def) => {
if def == self.macro_def(ident.span.ctxt()) {
ident.span.remove_mark();
}
}
_ => {
// Do not resolve labels across function boundary
return None;
}
}
let r = pred(rib, ident);
if r.is_some() {
return r;
}
}
None
}
fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
self.with_current_self_item(item, |this| {
this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
let item_def_id = this.definitions.local_def_id(item.id);
this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
visit::walk_item(this, item);
});
});
});
}
fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
let segments = &use_tree.prefix.segments;
if !segments.is_empty() {
let ident = segments[0].ident;
if ident.is_path_segment_keyword() || ident.span.rust_2015() {
return;
}
let nss = match use_tree.kind {
ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
_ => &[TypeNS],
};
let report_error = |this: &Self, ns| {
let what = if ns == TypeNS { "type parameters" } else { "local variables" };
this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
};
for &ns in nss {
match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
Some(LexicalScopeBinding::Def(..)) => {
report_error(self, ns);
}
Some(LexicalScopeBinding::Item(binding)) => {
let orig_blacklisted_binding =
mem::replace(&mut self.blacklisted_binding, Some(binding));
if let Some(LexicalScopeBinding::Def(..)) =
self.resolve_ident_in_lexical_scope(ident, ns, None,
use_tree.prefix.span) {
report_error(self, ns);
}
self.blacklisted_binding = orig_blacklisted_binding;
}
None => {}
}
}
} else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
for (use_tree, _) in use_trees {
self.future_proof_import(use_tree);
}
}
}
fn resolve_item(&mut self, item: &Item) {
let name = item.ident.name;
debug!("(resolving item) resolving {}", name);
match item.node {
ItemKind::Ty(_, ref generics) |
ItemKind::Fn(_, _, ref generics, _) |
ItemKind::Existential(_, ref generics) => {
self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
|this| visit::walk_item(this, item));
}
ItemKind::Enum(_, ref generics) |
ItemKind::Struct(_, ref generics) |
ItemKind::Union(_, ref generics) => {
self.resolve_adt(item, generics);
}
ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
self.resolve_implementation(generics,
opt_trait_ref,
&self_type,
item.id,
impl_items),
ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
// Create a new rib for the trait-wide type parameters.
self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
let local_def_id = this.definitions.local_def_id(item.id);
this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
this.visit_generics(generics);
walk_list!(this, visit_param_bound, bounds);
for trait_item in trait_items {
let type_parameters = HasTypeParameters(&trait_item.generics,
TraitOrImplItemRibKind);
this.with_type_parameter_rib(type_parameters, |this| {
match trait_item.node {
TraitItemKind::Const(ref ty, ref default) => {
this.visit_ty(ty);
// Only impose the restrictions of
// ConstRibKind for an actual constant
// expression in a provided default.
if let Some(ref expr) = *default{
this.with_constant_rib(|this| {
this.visit_expr(expr);
});
}
}
TraitItemKind::Method(_, _) => {
visit::walk_trait_item(this, trait_item)
}
TraitItemKind::Type(..) => {
visit::walk_trait_item(this, trait_item)
}
TraitItemKind::Macro(_) => {
panic!("unexpanded macro in resolve!")
}
};
});
}
});
});
}
ItemKind::TraitAlias(ref generics, ref bounds) => {
// Create a new rib for the trait-wide type parameters.
self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
let local_def_id = this.definitions.local_def_id(item.id);
this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
this.visit_generics(generics);
walk_list!(this, visit_param_bound, bounds);
});
});
}
ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
self.with_scope(item.id, |this| {
visit::walk_item(this, item);
});
}
ItemKind::Static(ref ty, _, ref expr) |
ItemKind::Const(ref ty, ref expr) => {
self.with_item_rib(|this| {
this.visit_ty(ty);
this.with_constant_rib(|this| {
this.visit_expr(expr);
});
});
}
ItemKind::Use(ref use_tree) => {
self.future_proof_import(use_tree);
}
ItemKind::ExternCrate(..) |
ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
// do nothing, these are just around to be encoded
}
ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
}
}
fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
where F: FnOnce(&mut Resolver)
{
match type_parameters {
HasTypeParameters(generics, rib_kind) => {
let mut function_type_rib = Rib::new(rib_kind);
let mut seen_bindings = FxHashMap::default();
for param in &generics.params {
match param.kind {
GenericParamKind::Lifetime { .. } => {}
GenericParamKind::Type { .. } => {
let ident = param.ident.modern();
debug!("with_type_parameter_rib: {}", param.id);
if seen_bindings.contains_key(&ident) {
let span = seen_bindings.get(&ident).unwrap();
let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
ident.name,
span,
);
resolve_error(self, param.ident.span, err);
}
seen_bindings.entry(ident).or_insert(param.ident.span);
// Plain insert (no renaming).
let def = Def::TyParam(self.definitions.local_def_id(param.id));
function_type_rib.bindings.insert(ident, def);
self.record_def(param.id, PathResolution::new(def));
}
}
}
self.ribs[TypeNS].push(function_type_rib);
}
NoTypeParameters => {
// Nothing to do.
}
}
f(self);
if let HasTypeParameters(..) = type_parameters {
self.ribs[TypeNS].pop();
}
}
fn with_label_rib<F>(&mut self, f: F)
where F: FnOnce(&mut Resolver)
{
self.label_ribs.push(Rib::new(NormalRibKind));
f(self);
self.label_ribs.pop();
}
fn with_item_rib<F>(&mut self, f: F)
where F: FnOnce(&mut Resolver)
{
self.ribs[ValueNS].push(Rib::new(ItemRibKind));
self.ribs[TypeNS].push(Rib::new(ItemRibKind));
f(self);
self.ribs[TypeNS].pop();
self.ribs[ValueNS].pop();
}
fn with_constant_rib<F>(&mut self, f: F)
where F: FnOnce(&mut Resolver)
{
self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
self.label_ribs.push(Rib::new(ConstantItemRibKind));
f(self);
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
where F: FnOnce(&mut Resolver) -> T
{
// Handle nested impls (inside fn bodies)
let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
let result = f(self);
self.current_self_type = previous_value;
result
}
fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
where F: FnOnce(&mut Resolver) -> T
{
let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
let result = f(self);
self.current_self_item = previous_value;
result
}
/// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
where F: FnOnce(&mut Resolver, Option<DefId>) -> T
{
let mut new_val = None;
let mut new_id = None;
if let Some(trait_ref) = opt_trait_ref {
let path: Vec<_> = Segment::from_path(&trait_ref.path);
let def = self.smart_resolve_path_fragment(
trait_ref.ref_id,
None,
&path,
trait_ref.path.span,
PathSource::Trait(AliasPossibility::No),
CrateLint::SimplePath(trait_ref.ref_id),
).base_def();
if def != Def::Err {
new_id = Some(def.def_id());
let span = trait_ref.path.span;
if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
self.resolve_path_without_parent_scope(
&path,
Some(TypeNS),
false,
span,
CrateLint::SimplePath(trait_ref.ref_id),
)
{
new_val = Some((module, trait_ref.clone()));
}
}
}
let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
let result = f(self, new_id);
self.current_trait_ref = original_trait_ref;
result
}
fn with_self_rib<F>(&mut self, self_def: Def, f: F)
where F: FnOnce(&mut Resolver)
{
let mut self_type_rib = Rib::new(NormalRibKind);
// plain insert (no renaming, types are not currently hygienic....)
self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
self.ribs[TypeNS].push(self_type_rib);
f(self);
self.ribs[TypeNS].pop();
}
fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
where F: FnOnce(&mut Resolver)
{
let self_def = Def::SelfCtor(impl_id);
let mut self_type_rib = Rib::new(NormalRibKind);
self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
self.ribs[ValueNS].push(self_type_rib);
f(self);
self.ribs[ValueNS].pop();
}
fn resolve_implementation(&mut self,
generics: &Generics,
opt_trait_reference: &Option<TraitRef>,
self_type: &Ty,
item_id: NodeId,
impl_items: &[ImplItem]) {
// If applicable, create a rib for the type parameters.
self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
// Dummy self type for better errors if `Self` is used in the trait path.
this.with_self_rib(Def::SelfTy(None, None), |this| {
// Resolve the trait reference, if necessary.
this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
let item_def_id = this.definitions.local_def_id(item_id);
this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
if let Some(trait_ref) = opt_trait_reference.as_ref() {
// Resolve type arguments in the trait path.
visit::walk_trait_ref(this, trait_ref);
}
// Resolve the self type.
this.visit_ty(self_type);
// Resolve the type parameters.
this.visit_generics(generics);
// Resolve the items within the impl.
this.with_current_self_type(self_type, |this| {
this.with_self_struct_ctor_rib(item_def_id, |this| {
for impl_item in impl_items {
this.resolve_visibility(&impl_item.vis);
// We also need a new scope for the impl item type parameters.
let type_parameters = HasTypeParameters(&impl_item.generics,
TraitOrImplItemRibKind);
this.with_type_parameter_rib(type_parameters, |this| {
use self::ResolutionError::*;
match impl_item.node {
ImplItemKind::Const(..) => {
// If this is a trait impl, ensure the const
// exists in trait
this.check_trait_item(impl_item.ident,
ValueNS,
impl_item.span,
|n, s| ConstNotMemberOfTrait(n, s));
this.with_constant_rib(|this|
visit::walk_impl_item(this, impl_item)
);
}
ImplItemKind::Method(..) => {
// If this is a trait impl, ensure the method
// exists in trait
this.check_trait_item(impl_item.ident,
ValueNS,
impl_item.span,
|n, s| MethodNotMemberOfTrait(n, s));
visit::walk_impl_item(this, impl_item);
}
ImplItemKind::Type(ref ty) => {
// If this is a trait impl, ensure the type
// exists in trait
this.check_trait_item(impl_item.ident,
TypeNS,
impl_item.span,
|n, s| TypeNotMemberOfTrait(n, s));
this.visit_ty(ty);
}
ImplItemKind::Existential(ref bounds) => {
// If this is a trait impl, ensure the type
// exists in trait
this.check_trait_item(impl_item.ident,
TypeNS,
impl_item.span,
|n, s| TypeNotMemberOfTrait(n, s));
for bound in bounds {
this.visit_param_bound(bound);
}
}
ImplItemKind::Macro(_) =>
panic!("unexpanded macro in resolve!"),
}
});
}
});
});
});
});
});
});
}
fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
where F: FnOnce(Name, &str) -> ResolutionError
{
// If there is a TraitRef in scope for an impl, then the method must be in the
// trait.
if let Some((module, _)) = self.current_trait_ref {
if self.resolve_ident_in_module(
ModuleOrUniformRoot::Module(module),
ident,
ns,
None,
false,
span,
).is_err() {
let path = &self.current_trait_ref.as_ref().unwrap().1.path;
resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
}
}
}
fn resolve_local(&mut self, local: &Local) {
// Resolve the type.
walk_list!(self, visit_ty, &local.ty);
// Resolve the initializer.
walk_list!(self, visit_expr, &local.init);
// Resolve the pattern.
self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
}
// build a map from pattern identifiers to binding-info's.
// this is done hygienically. This could arise for a macro
// that expands into an or-pattern where one 'x' was from the
// user and one 'x' came from the macro.
fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
let mut binding_map = FxHashMap::default();
pat.walk(&mut |pat| {
if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
Some(Def::Local(..)) => true,
_ => false,
} {
let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
binding_map.insert(ident, binding_info);
}
}
true
});
binding_map
}
// check that all of the arms in an or-pattern have exactly the
// same set of bindings, with the same binding modes for each.
fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
if pats.is_empty() {
return;
}
let mut missing_vars = FxHashMap::default();
let mut inconsistent_vars = FxHashMap::default();
for (i, p) in pats.iter().enumerate() {
let map_i = self.binding_mode_map(&p);
for (j, q) in pats.iter().enumerate() {
if i == j {
continue;
}
let map_j = self.binding_mode_map(&q);
for (&key, &binding_i) in &map_i {
if map_j.is_empty() { // Account for missing bindings when
let binding_error = missing_vars // map_j has none.
.entry(key.name)
.or_insert(BindingError {
name: key.name,
origin: BTreeSet::new(),
target: BTreeSet::new(),
});
binding_error.origin.insert(binding_i.span);
binding_error.target.insert(q.span);
}
for (&key_j, &binding_j) in &map_j {
match map_i.get(&key_j) {
None => { // missing binding
let binding_error = missing_vars
.entry(key_j.name)
.or_insert(BindingError {
name: key_j.name,
origin: BTreeSet::new(),
target: BTreeSet::new(),
});
binding_error.origin.insert(binding_j.span);
binding_error.target.insert(p.span);
}
Some(binding_i) => { // check consistent binding
if binding_i.binding_mode != binding_j.binding_mode {
inconsistent_vars
.entry(key.name)
.or_insert((binding_j.span, binding_i.span));
}
}
}
}
}
}
}
let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
missing_vars.sort();
for (_, v) in missing_vars {
resolve_error(self,
*v.origin.iter().next().unwrap(),
ResolutionError::VariableNotBoundInPattern(v));
}
let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
inconsistent_vars.sort();
for (name, v) in inconsistent_vars {
resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
}
}
fn resolve_arm(&mut self, arm: &Arm) {
self.ribs[ValueNS].push(Rib::new(NormalRibKind));
let mut bindings_list = FxHashMap::default();
for pattern in &arm.pats {
self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
}
// This has to happen *after* we determine which pat_idents are variants
self.check_consistent_bindings(&arm.pats);
if let Some(ast::Guard::If(ref expr)) = arm.guard {
self.visit_expr(expr)
}
self.visit_expr(&arm.body);
self.ribs[ValueNS].pop();
}
fn resolve_block(&mut self, block: &Block) {
debug!("(resolving block) entering block");
// Move down in the graph, if there's an anonymous module rooted here.
let orig_module = self.current_module;
let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
let mut num_macro_definition_ribs = 0;
if let Some(anonymous_module) = anonymous_module {
debug!("(resolving block) found anonymous module, moving down");
self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
self.current_module = anonymous_module;
self.finalize_current_module_macro_resolutions();
} else {
self.ribs[ValueNS].push(Rib::new(NormalRibKind));
}
// Descend into the block.
for stmt in &block.stmts {
if let ast::StmtKind::Item(ref item) = stmt.node {
if let ast::ItemKind::MacroDef(..) = item.node {
num_macro_definition_ribs += 1;
let def = self.definitions.local_def_id(item.id);
self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
self.label_ribs.push(Rib::new(MacroDefinition(def)));
}
}
self.visit_stmt(stmt);
}
// Move back up.
self.current_module = orig_module;
for _ in 0 .. num_macro_definition_ribs {
self.ribs[ValueNS].pop();
self.label_ribs.pop();
}
self.ribs[ValueNS].pop();
if anonymous_module.is_some() {
self.ribs[TypeNS].pop();
}
debug!("(resolving block) leaving block");
}
fn fresh_binding(&mut self,
ident: Ident,
pat_id: NodeId,
outer_pat_id: NodeId,
pat_src: PatternSource,
bindings: &mut FxHashMap<Ident, NodeId>)
-> PathResolution {
// Add the binding to the local ribs, if it
// doesn't already exist in the bindings map. (We
// must not add it if it's in the bindings map
// because that breaks the assumptions later
// passes make about or-patterns.)
let ident = ident.modern_and_legacy();
let mut def = Def::Local(pat_id);
match bindings.get(&ident).cloned() {
Some(id) if id == outer_pat_id => {
// `Variant(a, a)`, error
resolve_error(
self,
ident.span,
ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
&ident.as_str())
);
}
Some(..) if pat_src == PatternSource::FnParam => {
// `fn f(a: u8, a: u8)`, error
resolve_error(
self,
ident.span,
ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
&ident.as_str())
);
}
Some(..) if pat_src == PatternSource::Match ||
pat_src == PatternSource::IfLet ||
pat_src == PatternSource::WhileLet => {
// `Variant1(a) | Variant2(a)`, ok
// Reuse definition from the first `a`.
def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
}
Some(..) => {
span_bug!(ident.span, "two bindings with the same name from \
unexpected pattern source {:?}", pat_src);
}
None => {
// A completely fresh binding, add to the lists if it's valid.
if ident.name != keywords::Invalid.name() {
bindings.insert(ident, outer_pat_id);
self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
}
}
}
PathResolution::new(def)
}
fn resolve_pattern(&mut self,
pat: &Pat,
pat_src: PatternSource,
// Maps idents to the node ID for the
// outermost pattern that binds them.
bindings: &mut FxHashMap<Ident, NodeId>) {
// Visit all direct subpatterns of this pattern.
let outer_pat_id = pat.id;
pat.walk(&mut |pat| {
match pat.node {
PatKind::Ident(bmode, ident, ref opt_pat) => {
// First try to resolve the identifier as some existing
// entity, then fall back to a fresh binding.
let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
None, pat.span)
.and_then(LexicalScopeBinding::item);
let resolution = binding.map(NameBinding::def).and_then(|def| {
let is_syntactic_ambiguity = opt_pat.is_none() &&
bmode == BindingMode::ByValue(Mutability::Immutable);
match def {
Def::StructCtor(_, CtorKind::Const) |
Def::VariantCtor(_, CtorKind::Const) |
Def::Const(..) if is_syntactic_ambiguity => {
// Disambiguate in favor of a unit struct/variant
// or constant pattern.
self.record_use(ident, ValueNS, binding.unwrap(), false);
Some(PathResolution::new(def))
}
Def::StructCtor(..) | Def::VariantCtor(..) |
Def::Const(..) | Def::Static(..) => {
// This is unambiguously a fresh binding, either syntactically
// (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
// to something unusable as a pattern (e.g. constructor function),
// but we still conservatively report an error, see
// issues/33118#issuecomment-233962221 for one reason why.
resolve_error(
self,
ident.span,
ResolutionError::BindingShadowsSomethingUnacceptable(
pat_src.descr(), ident.name, binding.unwrap())
);
None
}
Def::Fn(..) | Def::Err => {
// These entities are explicitly allowed
// to be shadowed by fresh bindings.
None
}
def => {
span_bug!(ident.span, "unexpected definition for an \
identifier in pattern: {:?}", def);
}
}
}).unwrap_or_else(|| {
self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
});
self.record_def(pat.id, resolution);
}
PatKind::TupleStruct(ref path, ..) => {
self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
}
PatKind::Path(ref qself, ref path) => {
self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
}
PatKind::Struct(ref path, ..) => {
self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
}
_ => {}
}
true
});
visit::walk_pat(self, pat);
}
// High-level and context dependent path resolution routine.
// Resolves the path and records the resolution into definition map.
// If resolution fails tries several techniques to find likely
// resolution candidates, suggest imports or other help, and report
// errors in user friendly way.
fn smart_resolve_path(&mut self,
id: NodeId,
qself: Option<&QSelf>,
path: &Path,
source: PathSource)
-> PathResolution {
self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
}
/// A variant of `smart_resolve_path` where you also specify extra
/// information about where the path came from; this extra info is
/// sometimes needed for the lint that recommends rewriting
/// absolute paths to `crate`, so that it knows how to frame the
/// suggestion. If you are just resolving a path like `foo::bar`
/// that appears...somewhere, though, then you just want
/// `CrateLint::SimplePath`, which is what `smart_resolve_path`
/// already provides.
fn smart_resolve_path_with_crate_lint(
&mut self,
id: NodeId,
qself: Option<&QSelf>,
path: &Path,
source: PathSource,
crate_lint: CrateLint
) -> PathResolution {
self.smart_resolve_path_fragment(
id,
qself,
&Segment::from_path(path),
path.span,
source,
crate_lint,
)
}
fn smart_resolve_path_fragment(&mut self,
id: NodeId,
qself: Option<&QSelf>,
path: &[Segment],
span: Span,
source: PathSource,
crate_lint: CrateLint)
-> PathResolution {
let ident_span = path.last().map_or(span, |ident| ident.ident.span);
let ns = source.namespace();
let is_expected = &|def| source.is_expected(def);
let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
// Base error is amended with one short label and possibly some longer helps/notes.
let report_errors = |this: &mut Self, def: Option<Def>| {
// Make the base error.
let expected = source.descr_expected();
let path_str = Segment::names_to_string(path);
let item_str = path.last().unwrap().ident;
let code = source.error_code(def.is_some());
let (base_msg, fallback_label, base_span) = if let Some(def) = def {
(format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
format!("not a {}", expected),
span)
} else {
let item_span = path.last().unwrap().ident.span;
let (mod_prefix, mod_str) = if path.len() == 1 {
(String::new(), "this scope".to_string())
} else if path.len() == 2 && path[0].ident.name == keywords::CrateRoot.name() {
(String::new(), "the crate root".to_string())
} else {
let mod_path = &path[..path.len() - 1];
let mod_prefix = match this.resolve_path_without_parent_scope(
mod_path, Some(TypeNS), false, span, CrateLint::No
) {
PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
module.def(),
_ => None,
}.map_or(String::new(), |def| format!("{} ", def.kind_name()));
(mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
};
(format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
format!("not found in {}", mod_str),
item_span)
};
let code = DiagnosticId::Error(code.into());
let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
// Emit help message for fake-self from other languages like `this`(javascript)
if ["this", "my"].contains(&&*item_str.as_str())
&& this.self_value_is_available(path[0].ident.span, span) {
err.span_suggestion_with_applicability(
span,
"did you mean",
"self".to_string(),
Applicability::MaybeIncorrect,
);
}
// Emit special messages for unresolved `Self` and `self`.
if is_self_type(path, ns) {
__diagnostic_used!(E0411);
err.code(DiagnosticId::Error("E0411".into()));
err.span_label(span, format!("`Self` is only available in impls, traits, \
and type definitions"));
return (err, Vec::new());
}
if is_self_value(path, ns) {
__diagnostic_used!(E0424);
err.code(DiagnosticId::Error("E0424".into()));
err.span_label(span, format!("`self` value is a keyword \
only available in \
methods with `self` parameter"));
return (err, Vec::new());
}
// Try to lookup the name in more relaxed fashion for better error reporting.
let ident = path.last().unwrap().ident;
let candidates = this.lookup_import_candidates(ident, ns, is_expected);
if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
let enum_candidates =
this.lookup_import_candidates(ident, ns, is_enum_variant);
let mut enum_candidates = enum_candidates.iter()
.map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
enum_candidates.sort();
for (sp, variant_path, enum_path) in enum_candidates {
if sp.is_dummy() {
let msg = format!("there is an enum variant `{}`, \
try using `{}`?",
variant_path,
enum_path);
err.help(&msg);
} else {
err.span_suggestion_with_applicability(
span,
"you can try using the variant's enum",
enum_path,
Applicability::MachineApplicable,
);
}
}
}
if path.len() == 1 && this.self_type_is_available(span) {
if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
let self_is_available = this.self_value_is_available(path[0].ident.span, span);
match candidate {
AssocSuggestion::Field => {
err.span_suggestion_with_applicability(
span,
"try",
format!("self.{}", path_str),
Applicability::MachineApplicable,
);
if !self_is_available {
err.span_label(span, format!("`self` value is a keyword \
only available in \
methods with `self` parameter"));
}
}
AssocSuggestion::MethodWithSelf if self_is_available => {
err.span_suggestion_with_applicability(
span,
"try",
format!("self.{}", path_str),
Applicability::MachineApplicable,
);
}
AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
err.span_suggestion_with_applicability(
span,
"try",
format!("Self::{}", path_str),
Applicability::MachineApplicable,
);
}
}
return (err, candidates);
}
}
let mut levenshtein_worked = false;
// Try Levenshtein.
if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
err.span_label(ident_span, format!("did you mean `{}`?", candidate));
levenshtein_worked = true;
}
// Try context dependent help if relaxed lookup didn't work.
if let Some(def) = def {
match (def, source) {
(Def::Macro(..), _) => {
err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
return (err, candidates);
}
(Def::TyAlias(..), PathSource::Trait(_)) => {
err.span_label(span, "type aliases cannot be used as traits");
if nightly_options::is_nightly_build() {
err.note("did you mean to use a trait alias?");
}
return (err, candidates);
}
(Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
ExprKind::Field(_, ident) => {
err.span_label(parent.span, format!("did you mean `{}::{}`?",
path_str, ident));
return (err, candidates);
}
ExprKind::MethodCall(ref segment, ..) => {
err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
path_str, segment.ident));
return (err, candidates);
}
_ => {}
},
(Def::Enum(..), PathSource::TupleStruct)
| (Def::Enum(..), PathSource::Expr(..)) => {
if let Some(variants) = this.collect_enum_variants(def) {
err.note(&format!("did you mean to use one \
of the following variants?\n{}",
variants.iter()
.map(|suggestion| path_names_to_string(suggestion))
.map(|suggestion| format!("- `{}`", suggestion))
.collect::<Vec<_>>()
.join("\n")));
} else {
err.note("did you mean to use one of the enum's variants?");
}
return (err, candidates);
},
(Def::Struct(def_id), _) if ns == ValueNS => {
if let Some((ctor_def, ctor_vis))
= this.struct_constructors.get(&def_id).cloned() {
let accessible_ctor = this.is_accessible(ctor_vis);
if is_expected(ctor_def) && !accessible_ctor {
err.span_label(span, format!("constructor is not visible \
here due to private fields"));
}
} else {
// HACK(estebank): find a better way to figure out that this was a
// parser issue where a struct literal is being used on an expression
// where a brace being opened means a block is being started. Look
// ahead for the next text to see if `span` is followed by a `{`.
let sm = this.session.source_map();
let mut sp = span;
loop {
sp = sm.next_point(sp);
match sm.span_to_snippet(sp) {
Ok(ref snippet) => {
if snippet.chars().any(|c| { !c.is_whitespace() }) {
break;
}
}
_ => break,
}
}
let followed_by_brace = match sm.span_to_snippet(sp) {
Ok(ref snippet) if snippet == "{" => true,
_ => false,
};
match source {
PathSource::Expr(Some(parent)) => {
match parent.node {
ExprKind::MethodCall(ref path_assignment, _) => {
err.span_suggestion_with_applicability(
sm.start_point(parent.span)
.to(path_assignment.ident.span),
"use `::` to access an associated function",
format!("{}::{}",
path_str,
path_assignment.ident),
Applicability::MaybeIncorrect
);
return (err, candidates);
},
_ => {
err.span_label(
span,
format!("did you mean `{} {{ /* fields */ }}`?",
path_str),
);
return (err, candidates);
},
}
},
PathSource::Expr(None) if followed_by_brace == true => {
err.span_label(
span,
format!("did you mean `({} {{ /* fields */ }})`?",
path_str),
);
return (err, candidates);
},
_ => {
err.span_label(
span,
format!("did you mean `{} {{ /* fields */ }}`?",
path_str),
);
return (err, candidates);
},
}
}
return (err, candidates);
}
(Def::Union(..), _) |
(Def::Variant(..), _) |
(Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
path_str));
return (err, candidates);
}
(Def::SelfTy(..), _) if ns == ValueNS => {
err.span_label(span, fallback_label);
err.note("can't use `Self` as a constructor, you must use the \
implemented struct");
return (err, candidates);
}
(Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
err.note("can't use a type alias as a constructor");
return (err, candidates);
}
_ => {}
}
}
// Fallback label.
if !levenshtein_worked {
err.span_label(base_span, fallback_label);
this.type_ascription_suggestion(&mut err, base_span);
}
(err, candidates)
};
let report_errors = |this: &mut Self, def: Option<Def>| {
let (err, candidates) = report_errors(this, def);
let def_id = this.current_module.normal_ancestor_id;
let node_id = this.definitions.as_local_node_id(def_id).unwrap();
let better = def.is_some();
this.use_injections.push(UseError { err, candidates, node_id, better });
err_path_resolution()
};
let resolution = match self.resolve_qpath_anywhere(
id,
qself,
path,
ns,
span,
source.defer_to_typeck(),
source.global_by_default(),
crate_lint,
) {
Some(resolution) if resolution.unresolved_segments() == 0 => {
if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
resolution
} else {
// Add a temporary hack to smooth the transition to new struct ctor
// visibility rules. See #38932 for more details.
let mut res = None;
if let Def::Struct(def_id) = resolution.base_def() {
if let Some((ctor_def, ctor_vis))
= self.struct_constructors.get(&def_id).cloned() {
if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
self.session.buffer_lint(lint, id, span,
"private struct constructors are not usable through \
re-exports in outer modules",
);
res = Some(PathResolution::new(ctor_def));
}
}
}
res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
}
}
Some(resolution) if source.defer_to_typeck() => {
// Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
// or `<T>::A::B`. If `B` should be resolved in value namespace then
// it needs to be added to the trait map.
if ns == ValueNS {
let item_name = path.last().unwrap().ident;
let traits = self.get_traits_containing_item(item_name, ns);
self.trait_map.insert(id, traits);
}
resolution
}
_ => report_errors(self, None)
};
if let PathSource::TraitItem(..) = source {} else {
// Avoid recording definition of `A::B` in `<T as A>::B::C`.
self.record_def(id, resolution);
}
resolution
}
fn type_ascription_suggestion(&self,
err: &mut DiagnosticBuilder,
base_span: Span) {
debug!("type_ascription_suggetion {:?}", base_span);
let cm = self.session.source_map();
debug!("self.current_type_ascription {:?}", self.current_type_ascription);
if let Some(sp) = self.current_type_ascription.last() {
let mut sp = *sp;
loop { // try to find the `:`, bail on first non-':'/non-whitespace
sp = cm.next_point(sp);
if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
debug!("snippet {:?}", snippet);
let line_sp = cm.lookup_char_pos(sp.hi()).line;
let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
debug!("{:?} {:?}", line_sp, line_base_sp);
if snippet == ":" {
err.span_label(base_span,
"expecting a type here because of type ascription");
if line_sp != line_base_sp {
err.span_suggestion_short_with_applicability(
sp,
"did you mean to use `;` here instead?",
";".to_string(),
Applicability::MaybeIncorrect,
);
}
break;
} else if !snippet.trim().is_empty() {
debug!("tried to find type ascription `:` token, couldn't find it");
break;
}
} else {
break;
}
}
}
}
fn self_type_is_available(&mut self, span: Span) -> bool {
let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
TypeNS, None, span);
if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
}
fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
let ident = Ident::new(keywords::SelfValue.name(), self_span);
let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
}
// Resolve in alternative namespaces if resolution in the primary namespace fails.
fn resolve_qpath_anywhere(&mut self,
id: NodeId,
qself: Option<&QSelf>,
path: &[Segment],
primary_ns: Namespace,
span: Span,
defer_to_typeck: bool,
global_by_default: bool,
crate_lint: CrateLint)
-> Option<PathResolution> {
let mut fin_res = None;
// FIXME: can't resolve paths in macro namespace yet, macros are
// processed by the little special hack below.
for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
if i == 0 || ns != primary_ns {
match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
// If defer_to_typeck, then resolution > no resolution,
// otherwise full resolution > partial resolution > no resolution.
Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
return Some(res),
res => if fin_res.is_none() { fin_res = res },
};
}
}
if primary_ns != MacroNS &&
(self.macro_names.contains(&path[0].ident.modern()) ||
self.builtin_macros.get(&path[0].ident.name).cloned()
.and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
self.macro_use_prelude.get(&path[0].ident.name).cloned()
.and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
// Return some dummy definition, it's enough for error reporting.
return Some(
PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
);
}
fin_res
}
/// Handles paths that may refer to associated items.
fn resolve_qpath(&mut self,
id: NodeId,
qself: Option<&QSelf>,
path: &[Segment],
ns: Namespace,
span: Span,
global_by_default: bool,
crate_lint: CrateLint)
-> Option<PathResolution> {
debug!(
"resolve_qpath(id={:?}, qself={:?}, path={:?}, \
ns={:?}, span={:?}, global_by_default={:?})",
id,
qself,
path,
ns,
span,
global_by_default,
);
if let Some(qself) = qself {
if qself.position == 0 {
// This is a case like `<T>::B`, where there is no
// trait to resolve. In that case, we leave the `B`
// segment to be resolved by type-check.
return Some(PathResolution::with_unresolved_segments(
Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
));
}
// Make sure `A::B` in `<T as A::B>::C` is a trait item.
//
// Currently, `path` names the full item (`A::B::C`, in
// our example). so we extract the prefix of that that is
// the trait (the slice upto and including
// `qself.position`). And then we recursively resolve that,
// but with `qself` set to `None`.
//
// However, setting `qself` to none (but not changing the
// span) loses the information about where this path
// *actually* appears, so for the purposes of the crate
// lint we pass along information that this is the trait
// name from a fully qualified path, and this also
// contains the full span (the `CrateLint::QPathTrait`).
let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
let res = self.smart_resolve_path_fragment(
id,
None,
&path[..qself.position + 1],
span,
PathSource::TraitItem(ns),
CrateLint::QPathTrait {
qpath_id: id,
qpath_span: qself.path_span,
},
);
// The remaining segments (the `C` in our example) will
// have to be resolved by type-check, since that requires doing
// trait resolution.
return Some(PathResolution::with_unresolved_segments(
res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
));
}
let result = match self.resolve_path_without_parent_scope(
&path,
Some(ns),
true,
span,
crate_lint,
) {
PathResult::NonModule(path_res) => path_res,
PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
PathResolution::new(module.def().unwrap())
}
// In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
// don't report an error right away, but try to fallback to a primitive type.
// So, we are still able to successfully resolve something like
//
// use std::u8; // bring module u8 in scope
// fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
// u8::max_value() // OK, resolves to associated function <u8>::max_value,
// // not to non-existent std::u8::max_value
// }
//
// Such behavior is required for backward compatibility.
// The same fallback is used when `a` resolves to nothing.
PathResult::Module(ModuleOrUniformRoot::Module(_)) |
PathResult::Failed(..)
if (ns == TypeNS || path.len() > 1) &&
self.primitive_type_table.primitive_types
.contains_key(&path[0].ident.name) => {
let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
}
PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
PathResolution::new(module.def().unwrap()),
PathResult::Failed(span, msg, false) => {
resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
err_path_resolution()
}
PathResult::Module(..) | PathResult::Failed(..) => return None,
PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
};
if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
path[0].ident.name != keywords::CrateRoot.name() &&
path[0].ident.name != keywords::DollarCrate.name() {
let unqualified_result = {
match self.resolve_path_without_parent_scope(
&[*path.last().unwrap()],
Some(ns),
false,
span,
CrateLint::No,
) {
PathResult::NonModule(path_res) => path_res.base_def(),
PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
module.def().unwrap(),
_ => return Some(result),
}
};
if result.base_def() == unqualified_result {
let lint = lint::builtin::UNUSED_QUALIFICATIONS;
self.session.buffer_lint(lint, id, span, "unnecessary qualification")
}
}
Some(result)
}
fn resolve_path_without_parent_scope(
&mut self,
path: &[Segment],
opt_ns: Option<Namespace>, // `None` indicates a module path in import
record_used: bool,
path_span: Span,
crate_lint: CrateLint,
) -> PathResult<'a> {
// Macro and import paths must have full parent scope available during resolution,
// other paths will do okay with parent module alone.
assert!(opt_ns != None && opt_ns != Some(MacroNS));
let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
}
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> {
let mut module = None;
let mut allow_super = true;
let mut second_binding = None;
self.current_module = parent_scope.module;
debug!(
"resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
path_span={:?}, crate_lint={:?})",
path,
opt_ns,
record_used,
path_span,
crate_lint,
);
for (i, &Segment { ident, id }) in path.iter().enumerate() {
debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
let record_segment_def = |this: &mut Self, def| {
if record_used {
if let Some(id) = id {
if !this.def_map.contains_key(&id) {
assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
this.record_def(id, PathResolution::new(def));
}
}
}
};
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 == keywords::SelfValue.name() ||
name == keywords::Super.name());
if ns == TypeNS {
if allow_super && name == keywords::Super.name() {
let mut ctxt = ident.span.ctxt().modern();
let self_module = match i {
0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
_ => match module {
Some(ModuleOrUniformRoot::Module(module)) => Some(module),
_ => None,
},
};
if let Some(self_module) = self_module {
if let Some(parent) = self_module.parent {
module = Some(ModuleOrUniformRoot::Module(
self.resolve_self(&mut ctxt, parent)));
continue;
}
}
let msg = "there are too many initial `super`s.".to_string();
return PathResult::Failed(ident.span, msg, false);
}
if i == 0 {
if name == keywords::SelfValue.name() {
let mut ctxt = ident.span.ctxt().modern();
module = Some(ModuleOrUniformRoot::Module(
self.resolve_self(&mut ctxt, self.current_module)));
continue;
}
if name == keywords::Extern.name() ||
name == keywords::CrateRoot.name() && ident.span.rust_2018() {
module = Some(ModuleOrUniformRoot::ExternPrelude);
continue;
}
if name == keywords::CrateRoot.name() &&
ident.span.rust_2015() && self.session.rust_2018() {
// `::a::b` from 2015 macro on 2018 global edition
module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
continue;
}
if name == keywords::CrateRoot.name() ||
name == keywords::Crate.name() ||
name == keywords::DollarCrate.name() {
// `::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 == keywords::CrateRoot.name() {
"crate root".to_string()
} else {
format!("`{}`", name)
};
let msg = if i == 1 && path[0].ident.name == keywords::CrateRoot.name() {
format!("global paths cannot start with {}", name_str)
} else {
format!("{} in paths can only be used in start position", name_str)
};
return PathResult::Failed(ident.span, msg, false);
}
let binding = if let Some(module) = module {
self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
} else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
assert!(ns == TypeNS);
let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
record_used, path_span)
} else {
let record_used_id =
if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
// 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::Def(def))
if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
record_segment_def(self, def);
return PathResult::NonModule(PathResolution::with_unresolved_segments(
def, path.len() - 1
));
}
_ => Err(Determinacy::determined(record_used)),
}
};
match binding {
Ok(binding) => {
if i == 1 {
second_binding = Some(binding);
}
let def = binding.def();
let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
if let Some(next_module) = binding.module() {
module = Some(ModuleOrUniformRoot::Module(next_module));
record_segment_def(self, def);
} else if def == Def::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 def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
return PathResult::NonModule(PathResolution::new(def));
} else if def == Def::Err {
return PathResult::NonModule(err_path_resolution());
} 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(PathResolution::with_unresolved_segments(
def, path.len() - i - 1
));
} else {
return PathResult::Failed(ident.span,
format!("not a module `{}`", ident),
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(PathResolution::with_unresolved_segments(
module.def().unwrap(), path.len() - i
));
}
}
let module_def = match module {
Some(ModuleOrUniformRoot::Module(module)) => module.def(),
_ => None,
};
let msg = if module_def == self.graph_root.def() {
let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
let mut candidates =
self.lookup_import_candidates(ident, TypeNS, is_mod);
candidates.sort_by_cached_key(|c| {
(c.path.segments.len(), c.path.to_string())
});
if let Some(candidate) = candidates.get(0) {
format!("did you mean `{}`?", candidate.path)
} else {
format!("maybe a missing `extern crate {};`?", ident)
}
} else if i == 0 {
format!("use of undeclared type or module `{}`", ident)
} else {
format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
};
return PathResult::Failed(ident.span, msg, is_last);
}
}
}
self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
PathResult::Module(match module {
Some(module) => module,
None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
_ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
})
}
fn lint_if_path_starts_with_module(
&self,
crate_lint: CrateLint,
path: &[Segment],
path_span: Span,
second_binding: Option<&NameBinding>,
) {
let (diag_id, diag_span) = match crate_lint {
CrateLint::No => return,
CrateLint::SimplePath(id) => (id, path_span),
CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
};
let first_name = match path.get(0) {
// In the 2018 edition this lint is a hard error, so nothing to do
Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
_ => return,
};
// We're only interested in `use` paths which should start with
// `{{root}}` or `extern` currently.
if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
return
}
match path.get(1) {
// If this import looks like `crate::...` it's already good
Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
// Otherwise go below to see if it's an extern crate
Some(_) => {}
// If the path has length one (and it's `CrateRoot` most likely)
// then we don't know whether we're gonna be importing a crate or an
// item in our crate. Defer this lint to elsewhere
None => return,
}
// If the first element of our path was actually resolved to an
// `ExternCrate` (also used for `crate::...`) then no need to issue a
// warning, this looks all good!
if let Some(binding) = second_binding {
if let NameBindingKind::Import { directive: d, .. } = binding.kind {
// Careful: we still want to rewrite paths from
// renamed extern crates.
if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
return
}
}
}
let diag = lint::builtin::BuiltinLintDiagnostics
::AbsPathWithModule(diag_span);
self.session.buffer_lint_with_diagnostic(
lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
diag_id, diag_span,
"absolute paths must start with `self`, `super`, \
`crate`, or an external crate name in the 2018 edition",
diag);
}
// Resolve a local definition, potentially adjusting for closures.
fn adjust_local_def(&mut self,
ns: Namespace,
rib_index: usize,
mut def: Def,
record_used: bool,
span: Span) -> Def {
let ribs = &self.ribs[ns][rib_index + 1..];
// An invalid forward use of a type parameter from a previous default.
if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
if record_used {
resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
}
assert_eq!(def, Def::Err);
return Def::Err;
}
match def {
Def::Upvar(..) => {
span_bug!(span, "unexpected {:?} in bindings", def)
}
Def::Local(node_id) => {
for rib in ribs {
match rib.kind {
NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
ForwardTyParamBanRibKind => {
// Nothing to do. Continue.
}
ClosureRibKind(function_id) => {
let prev_def = def;
let seen = self.freevars_seen
.entry(function_id)
.or_default();
if let Some(&index) = seen.get(&node_id) {
def = Def::Upvar(node_id, index, function_id);
continue;
}
let vec = self.freevars
.entry(function_id)
.or_default();
let depth = vec.len();
def = Def::Upvar(node_id, depth, function_id);
if record_used {
vec.push(Freevar {
def: prev_def,
span,
});
seen.insert(node_id, depth);
}
}
ItemRibKind | TraitOrImplItemRibKind => {
// 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 {
resolve_error(self, span,
ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
}
return Def::Err;
}
ConstantItemRibKind => {
// Still doesn't deal with upvars
if record_used {
resolve_error(self, span,
ResolutionError::AttemptToUseNonConstantValueInConstant);
}
return Def::Err;
}
}
}
}
Def::TyParam(..) | Def::SelfTy(..) => {
for rib in ribs {
match rib.kind {
NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
ConstantItemRibKind => {
// Nothing to do. Continue.
}
ItemRibKind => {
// This was an attempt to use a type parameter outside
// its scope.
if record_used {
resolve_error(self, span,
ResolutionError::TypeParametersFromOuterFunction(def));
}
return Def::Err;
}
}
}
}
_ => {}
}
def
}
fn lookup_assoc_candidate<FilterFn>(&mut self,
ident: Ident,
ns: Namespace,
filter_fn: FilterFn)
-> Option<AssocSuggestion>
where FilterFn: Fn(Def) -> bool
{
fn extract_node_id(t: &Ty) -> Option<NodeId> {
match t.node {
TyKind::Path(None, _) => Some(t.id),
TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
// This doesn't handle the remaining `Ty` variants as they are not
// that commonly the self_type, it might be interesting to provide
// support for those in future.
_ => None,
}
}
// Fields are generally expected in the same contexts as locals.
if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
// Look for a field with the same name in the current self_type.
if let Some(resolution) = self.def_map.get(&node_id) {
match resolution.base_def() {
Def::Struct(did) | Def::Union(did)
if resolution.unresolved_segments() == 0 => {
if let Some(field_names) = self.field_names.get(&did) {
if field_names.iter().any(|&field_name| ident.name == field_name) {
return Some(AssocSuggestion::Field);
}
}
}
_ => {}
}
}
}
}
// Look for associated items in the current trait.
if let Some((module, _)) = self.current_trait_ref {
if let Ok(binding) = self.resolve_ident_in_module(
ModuleOrUniformRoot::Module(module),
ident,
ns,
None,
false,
module.span,
) {
let def = binding.def();
if filter_fn(def) {
return Some(if self.has_self.contains(&def.def_id()) {
AssocSuggestion::MethodWithSelf
} else {
AssocSuggestion::AssocItem
});
}
}
}
None
}
fn lookup_typo_candidate<FilterFn>(&mut self,
path: &[Segment],
ns: Namespace,
filter_fn: FilterFn,
span: Span)
-> Option<Symbol>
where FilterFn: Fn(Def) -> bool
{
let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
if let Some(binding) = resolution.borrow().binding {
if filter_fn(binding.def()) {
names.push(ident.name);
}
}
}
};
let mut names = Vec::new();
if path.len() == 1 {
// Search in lexical scope.
// Walk backwards up the ribs in scope and collect candidates.
for rib in self.ribs[ns].iter().rev() {
// Locals and type parameters
for (ident, def) in &rib.bindings {
if filter_fn(*def) {
names.push(ident.name);
}
}
// Items in scope
if let ModuleRibKind(module) = rib.kind {
// Items from this module
add_module_candidates(module, &mut names);
if let ModuleKind::Block(..) = module.kind {
// We can see through blocks
} else {
// Items from the prelude
if !module.no_implicit_prelude {
names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
if let Some(prelude) = self.prelude {
add_module_candidates(prelude, &mut names);
}
}
break;
}
}
}
// Add primitive types to the mix
if filter_fn(Def::PrimTy(Bool)) {
names.extend(
self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
)
}
} else {
// Search in module.
let mod_path = &path[..path.len() - 1];
if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
mod_path, Some(TypeNS), false, span, CrateLint::No
) {
if let ModuleOrUniformRoot::Module(module) = module {
add_module_candidates(module, &mut names);
}
}
}
let name = path[path.len() - 1].ident.name;
// Make sure error reporting is deterministic.
names.sort_by_cached_key(|name| name.as_str());
match find_best_match_for_name(names.iter(), &name.as_str(), None) {
Some(found) if found != name => Some(found),
_ => None,
}
}
fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
where F: FnOnce(&mut Resolver)
{
if let Some(label) = label {
self.unused_labels.insert(id, label.ident.span);
let def = Def::Label(id);
self.with_label_rib(|this| {
let ident = label.ident.modern_and_legacy();
this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
f(this);
});
} else {
f(self);
}
}
fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
self.with_resolved_label(label, id, |this| this.visit_block(block));
}
fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
// First, record candidate traits for this expression if it could
// result in the invocation of a method call.
self.record_candidate_traits_for_expr_if_necessary(expr);
// Next, resolve the node.
match expr.node {
ExprKind::Path(ref qself, ref path) => {
self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
visit::walk_expr(self, expr);
}
ExprKind::Struct(ref path, ..) => {
self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
visit::walk_expr(self, expr);
}
ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
let def = self.search_label(label.ident, |rib, ident| {
rib.bindings.get(&ident.modern_and_legacy()).cloned()
});
match def {
None => {
// Search again for close matches...
// Picks the first label that is "close enough", which is not necessarily
// the closest match
let close_match = self.search_label(label.ident, |rib, ident| {
let names = rib.bindings.iter().map(|(id, _)| &id.name);
find_best_match_for_name(names, &*ident.as_str(), None)
});
self.record_def(expr.id, err_path_resolution());
resolve_error(self,
label.ident.span,
ResolutionError::UndeclaredLabel(&label.ident.as_str(),
close_match));
}
Some(Def::Label(id)) => {
// Since this def is a label, it is never read.
self.record_def(expr.id, PathResolution::new(Def::Label(id)));
self.unused_labels.remove(&id);
}
Some(_) => {
span_bug!(expr.span, "label wasn't mapped to a label def!");
}
}
// visit `break` argument if any
visit::walk_expr(self, expr);
}
ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
self.visit_expr(subexpression);
self.ribs[ValueNS].push(Rib::new(NormalRibKind));
let mut bindings_list = FxHashMap::default();
for pat in pats {
self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
}
// This has to happen *after* we determine which pat_idents are variants
self.check_consistent_bindings(pats);
self.visit_block(if_block);
self.ribs[ValueNS].pop();
optional_else.as_ref().map(|expr| self.visit_expr(expr));
}
ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
ExprKind::While(ref subexpression, ref block, label) => {
self.with_resolved_label(label, expr.id, |this| {
this.visit_expr(subexpression);
this.visit_block(block);
});
}
ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
self.with_resolved_label(label, expr.id, |this| {
this.visit_expr(subexpression);
this.ribs[ValueNS].push(Rib::new(NormalRibKind));
let mut bindings_list = FxHashMap::default();
for pat in pats {
this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
}
// This has to happen *after* we determine which pat_idents are variants
this.check_consistent_bindings(pats);
this.visit_block(block);
this.ribs[ValueNS].pop();
});
}
ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
self.visit_expr(subexpression);
self.ribs[ValueNS].push(Rib::new(NormalRibKind));
self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
self.resolve_labeled_block(label, expr.id, block);
self.ribs[ValueNS].pop();
}
ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
// Equivalent to `visit::walk_expr` + passing some context to children.
ExprKind::Field(ref subexpression, _) => {
self.resolve_expr(subexpression, Some(expr));
}
ExprKind::MethodCall(ref segment, ref arguments) => {
let mut arguments = arguments.iter();
self.resolve_expr(arguments.next().unwrap(), Some(expr));
for argument in arguments {
self.resolve_expr(argument, None);
}
self.visit_path_segment(expr.span, segment);
}
ExprKind::Call(ref callee, ref arguments) => {
self.resolve_expr(callee, Some(expr));
for argument in arguments {
self.resolve_expr(argument, None);
}
}
ExprKind::Type(ref type_expr, _) => {
self.current_type_ascription.push(type_expr.span);
visit::walk_expr(self, expr);
self.current_type_ascription.pop();
}
// Resolve the body of async exprs inside the async closure to which they desugar
ExprKind::Async(_, async_closure_id, ref block) => {
let rib_kind = ClosureRibKind(async_closure_id);
self.ribs[ValueNS].push(Rib::new(rib_kind));
self.label_ribs.push(Rib::new(rib_kind));
self.visit_block(&block);
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
// `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
// resolve the arguments within the proper scopes so that usages of them inside the
// closure are detected as upvars rather than normal closure arg usages.
ExprKind::Closure(
_, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
ref fn_decl, ref body, _span,
) => {
let rib_kind = ClosureRibKind(expr.id);
self.ribs[ValueNS].push(Rib::new(rib_kind));
self.label_ribs.push(Rib::new(rib_kind));
// Resolve arguments:
let mut bindings_list = FxHashMap::default();
for argument in &fn_decl.inputs {
self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
self.visit_ty(&argument.ty);
}
// No need to resolve return type-- the outer closure return type is
// FunctionRetTy::Default
// Now resolve the inner closure
{
let rib_kind = ClosureRibKind(inner_closure_id);
self.ribs[ValueNS].push(Rib::new(rib_kind));
self.label_ribs.push(Rib::new(rib_kind));
// No need to resolve arguments: the inner closure has none.
// Resolve the return type:
visit::walk_fn_ret_ty(self, &fn_decl.output);
// Resolve the body
self.visit_expr(body);
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
_ => {
visit::walk_expr(self, expr);
}
}
}
fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
match expr.node {
ExprKind::Field(_, ident) => {
// FIXME(#6890): Even though you can't treat a method like a
// field, we need to add any trait methods we find that match
// the field name so that we can do some nice error reporting
// later on in typeck.
let traits = self.get_traits_containing_item(ident, ValueNS);
self.trait_map.insert(expr.id, traits);
}
ExprKind::MethodCall(ref segment, ..) => {
debug!("(recording candidate traits for expr) recording traits for {}",
expr.id);
let traits = self.get_traits_containing_item(segment.ident, ValueNS);
self.trait_map.insert(expr.id, traits);
}
_ => {
// Nothing to do.
}
}
}
fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
-> Vec<TraitCandidate> {
debug!("(getting traits containing item) looking for '{}'", ident.name);
let mut found_traits = Vec::new();
// Look for the current trait.
if let Some((module, _)) = self.current_trait_ref {
if self.resolve_ident_in_module(
ModuleOrUniformRoot::Module(module),
ident,
ns,
None,
false,
module.span,
).is_ok() {
let def_id = module.def_id().unwrap();
found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
}
}
ident.span = ident.span.modern();
let mut search_module = self.current_module;
loop {
self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
search_module = unwrap_or!(
self.hygienic_lexical_parent(search_module, &mut ident.span), break
);
}
if let Some(prelude) = self.prelude {
if !search_module.no_implicit_prelude {
self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
}
}
found_traits
}
fn get_traits_in_module_containing_item(&mut self,
ident: Ident,
ns: Namespace,
module: Module<'a>,
found_traits: &mut Vec<TraitCandidate>) {
assert!(ns == TypeNS || ns == ValueNS);
let mut traits = module.traits.borrow_mut();
if traits.is_none() {
let mut collected_traits = Vec::new();
module.for_each_child(|name, ns, binding| {
if ns != TypeNS { return }
if let Def::Trait(_) = binding.def() {
collected_traits.push((name, binding));
}
});
*traits = Some(collected_traits.into_boxed_slice());
}
for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
let module = binding.module().unwrap();
let mut ident = ident;
if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
continue
}
if self.resolve_ident_in_module_unadjusted(
ModuleOrUniformRoot::Module(module),
ident,
ns,
false,
module.span,
).is_ok() {
let import_id = match binding.kind {
NameBindingKind::Import { directive, .. } => {
self.maybe_unused_trait_imports.insert(directive.id);
self.add_to_glob_map(directive.id, trait_name);
Some(directive.id)
}
_ => None,
};
let trait_def_id = module.def_id().unwrap();
found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
}
}
}
fn lookup_import_candidates_from_module<FilterFn>(&mut self,
lookup_ident: Ident,
namespace: Namespace,
start_module: &'a ModuleData<'a>,
crate_name: Ident,
filter_fn: FilterFn)
-> Vec<ImportSuggestion>
where FilterFn: Fn(Def) -> bool
{
let mut candidates = Vec::new();
let mut seen_modules = FxHashSet::default();
let not_local_module = crate_name != keywords::Crate.ident();
let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
while let Some((in_module,
path_segments,
in_module_is_extern)) = worklist.pop() {
self.populate_module_if_necessary(in_module);
// We have to visit module children in deterministic order to avoid
// instabilities in reported imports (#43552).
in_module.for_each_child_stable(|ident, ns, name_binding| {
// avoid imports entirely
if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
// avoid non-importable candidates as well
if !name_binding.is_importable() { return; }
// collect results based on the filter function
if ident.name == lookup_ident.name && ns == namespace {
if filter_fn(name_binding.def()) {
// create the path
let mut segms = path_segments.clone();
if lookup_ident.span.rust_2018() {
// crate-local absolute paths start with `crate::` in edition 2018
// FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
segms.insert(
0, ast::PathSegment::from_ident(crate_name)
);
}
segms.push(ast::PathSegment::from_ident(ident));
let path = Path {
span: name_binding.span,
segments: segms,
};
// the entity is accessible in the following cases:
// 1. if it's defined in the same crate, it's always
// accessible (since private entities can be made public)
// 2. if it's defined in another crate, it's accessible
// only if both the module is public and the entity is
// declared as public (due to pruning, we don't explore
// outside crate private modules => no need to check this)
if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
candidates.push(ImportSuggestion { path });
}
}
}
// collect submodules to explore
if let Some(module) = name_binding.module() {
// form the path
let mut path_segments = path_segments.clone();
path_segments.push(ast::PathSegment::from_ident(ident));
let is_extern_crate_that_also_appears_in_prelude =
name_binding.is_extern_crate() &&
lookup_ident.span.rust_2018();
let is_visible_to_user =
!in_module_is_extern || name_binding.vis == ty::Visibility::Public;
if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
// add the module to the lookup
let is_extern = in_module_is_extern || name_binding.is_extern_crate();
if seen_modules.insert(module.def_id().unwrap()) {
worklist.push((module, path_segments, is_extern));
}
}
}
})
}
candidates
}
/// When name resolution fails, this method can be used to look up candidate
/// entities with the expected name. It allows filtering them using the
/// supplied predicate (which should be used to only accept the types of
/// definitions expected e.g. traits). The lookup spans across all crates.
///
/// NOTE: The method does not look into imports, but this is not a problem,
/// since we report the definitions (thus, the de-aliased imports).
fn lookup_import_candidates<FilterFn>(&mut self,
lookup_ident: Ident,
namespace: Namespace,
filter_fn: FilterFn)
-> Vec<ImportSuggestion>
where FilterFn: Fn(Def) -> bool
{
let mut suggestions = self.lookup_import_candidates_from_module(
lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
if lookup_ident.span.rust_2018() {
let extern_prelude_names = self.extern_prelude.clone();
for (ident, _) in extern_prelude_names.into_iter() {
if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
ident.span) {
let crate_root = self.get_module(DefId {
krate: crate_id,
index: CRATE_DEF_INDEX,
});
self.populate_module_if_necessary(&crate_root);
suggestions.extend(self.lookup_import_candidates_from_module(
lookup_ident, namespace, crate_root, ident, &filter_fn));
}
}
}
suggestions
}
fn find_module(&mut self,
module_def: Def)
-> Option<(Module<'a>, ImportSuggestion)>
{
let mut result = None;
let mut seen_modules = FxHashSet::default();
let mut worklist = vec![(self.graph_root, Vec::new())];
while let Some((in_module, path_segments)) = worklist.pop() {
// abort if the module is already found
if result.is_some() { break; }
self.populate_module_if_necessary(in_module);
in_module.for_each_child_stable(|ident, _, name_binding| {
// abort if the module is already found or if name_binding is private external
if result.is_some() || !name_binding.vis.is_visible_locally() {
return
}
if let Some(module) = name_binding.module() {
// form the path
let mut path_segments = path_segments.clone();
path_segments.push(ast::PathSegment::from_ident(ident));
if module.def() == Some(module_def) {
let path = Path {
span: name_binding.span,
segments: path_segments,
};
result = Some((module, ImportSuggestion { path }));
} else {
// add the module to the lookup
if seen_modules.insert(module.def_id().unwrap()) {
worklist.push((module, path_segments));
}
}
}
});
}
result
}
fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
if let Def::Enum(..) = enum_def {} else {
panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
}
self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
self.populate_module_if_necessary(enum_module);
let mut variants = Vec::new();
enum_module.for_each_child_stable(|ident, _, name_binding| {
if let Def::Variant(..) = name_binding.def() {
let mut segms = enum_import_suggestion.path.segments.clone();
segms.push(ast::PathSegment::from_ident(ident));
variants.push(Path {
span: name_binding.span,
segments: segms,
});
}
});
variants
})
}
fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
debug!("(recording def) recording {:?} for {}", resolution, node_id);
if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
}
}
fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
match vis.node {
ast::VisibilityKind::Public => ty::Visibility::Public,
ast::VisibilityKind::Crate(..) => {
ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
}
ast::VisibilityKind::Inherited => {
ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
}
ast::VisibilityKind::Restricted { ref path, id, .. } => {
// For visibilities we are not ready to provide correct implementation of "uniform
// paths" right now, so on 2018 edition we only allow module-relative paths for now.
// On 2015 edition visibilities are resolved as crate-relative by default,
// so we are prepending a root segment if necessary.
let ident = path.segments.get(0).expect("empty path in visibility").ident;
let crate_root = if ident.is_path_segment_keyword() {
None
} else if ident.span.rust_2018() {
let msg = "relative paths are not supported in visibilities on 2018 edition";
self.session.struct_span_err(ident.span, msg)
.span_suggestion(path.span, "try", format!("crate::{}", path))
.emit();
return ty::Visibility::Public;
} else {
let ctxt = ident.span.ctxt();
Some(Segment::from_ident(Ident::new(
keywords::CrateRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
)))
};
let segments = crate_root.into_iter()
.chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
let def = self.smart_resolve_path_fragment(
id,
None,
&segments,
path.span,
PathSource::Visibility,
CrateLint::SimplePath(id),
).base_def();
if def == Def::Err {
ty::Visibility::Public
} else {
let vis = ty::Visibility::Restricted(def.def_id());
if self.is_accessible(vis) {
vis
} else {
self.session.span_err(path.span, "visibilities can only be restricted \
to ancestor modules");
ty::Visibility::Public
}
}
}
}
}
fn is_accessible(&self, vis: ty::Visibility) -> bool {
vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
}
fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
vis.is_accessible_from(module.normal_ancestor_id, self)
}
fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
if !ptr::eq(module, old_module) {
span_bug!(binding.span, "parent module is reset for binding");
}
}
}
fn disambiguate_legacy_vs_modern(
&self,
legacy: &'a NameBinding<'a>,
modern: &'a NameBinding<'a>,
) -> bool {
// Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
// is disambiguated to mitigate regressions from macro modularization.
// Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
match (self.binding_parent_modules.get(&PtrKey(legacy)),
self.binding_parent_modules.get(&PtrKey(modern))) {
(Some(legacy), Some(modern)) =>
legacy.normal_ancestor_id == modern.normal_ancestor_id &&
modern.is_ancestor_of(legacy),
_ => false,
}
}
fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
if b.span.is_dummy() {
let add_built_in = match b.def() {
// These already contain the "built-in" prefix or look bad with it.
Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
_ => true,
};
let (built_in, from) = if from_prelude {
("", " from prelude")
} else if b.is_extern_crate() && !b.is_import() &&
self.session.opts.externs.get(&ident.as_str()).is_some() {
("", " passed with `--extern`")
} else if add_built_in {
(" built-in", "")
} else {
("", "")
};
let article = if built_in.is_empty() { b.article() } else { "a" };
format!("{a}{built_in} {thing}{from}",
a = article, thing = b.descr(), built_in = built_in, from = from)
} else {
let introduced = if b.is_import() { "imported" } else { "defined" };
format!("the {thing} {introduced} here",
thing = b.descr(), introduced = introduced)
}
}
fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
// We have to print the span-less alternative first, otherwise formatting looks bad.
(b2, b1, misc2, misc1, true)
} else {
(b1, b2, misc1, misc2, false)
};
let mut err = struct_span_err!(self.session, ident.span, E0659,
"`{ident}` is ambiguous ({why})",
ident = ident, why = kind.descr());
err.span_label(ident.span, "ambiguous name");
let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
let note_msg = format!("`{ident}` could{also} refer to {what}",
ident = ident, also = also, what = what);
let mut help_msgs = Vec::new();
if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
kind == AmbiguityKind::GlobVsExpanded ||
kind == AmbiguityKind::GlobVsOuter &&
swapped != also.is_empty()) {
help_msgs.push(format!("consider adding an explicit import of \
`{ident}` to disambiguate", ident = ident))
}
if b.is_extern_crate() && ident.span.rust_2018() {
help_msgs.push(format!(
"use `::{ident}` to refer to this {thing} unambiguously",
ident = ident, thing = b.descr(),
))
}
if misc == AmbiguityErrorMisc::SuggestCrate {
help_msgs.push(format!(
"use `crate::{ident}` to refer to this {thing} unambiguously",
ident = ident, thing = b.descr(),
))
} else if misc == AmbiguityErrorMisc::SuggestSelf {
help_msgs.push(format!(
"use `self::{ident}` to refer to this {thing} unambiguously",
ident = ident, thing = b.descr(),
))
}
if b.span.is_dummy() {
err.note(&note_msg);
} else {
err.span_note(b.span, &note_msg);
}
for (i, help_msg) in help_msgs.iter().enumerate() {
let or = if i == 0 { "" } else { "or " };
err.help(&format!("{}{}", or, help_msg));
}
};
could_refer_to(b1, misc1, "");
could_refer_to(b2, misc2, " also");
err.emit();
}
fn report_errors(&mut self, krate: &Crate) {
self.report_with_use_injections(krate);
for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
let msg = "macro-expanded `macro_export` macros from the current crate \
cannot be referred to by absolute paths";
self.session.buffer_lint_with_diagnostic(
lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
CRATE_NODE_ID, span_use, msg,
lint::builtin::BuiltinLintDiagnostics::
MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
);
}
for ambiguity_error in &self.ambiguity_errors {
self.report_ambiguity_error(ambiguity_error);
}
let mut reported_spans = FxHashSet::default();
for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
if reported_spans.insert(dedup_span) {
span_err!(self.session, ident.span, E0603, "{} `{}` is private",
binding.descr(), ident.name);
}
}
}
fn report_with_use_injections(&mut self, krate: &Crate) {
for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
let (span, found_use) = UsePlacementFinder::check(krate, node_id);
if !candidates.is_empty() {
show_candidates(&mut err, span, &candidates, better, found_use);
}
err.emit();
}
}
fn report_conflict<'b>(&mut self,
parent: Module,
ident: Ident,
ns: Namespace,
new_binding: &NameBinding<'b>,
old_binding: &NameBinding<'b>) {
// Error on the second of two conflicting names
if old_binding.span.lo() > new_binding.span.lo() {
return self.report_conflict(parent, ident, ns, old_binding, new_binding);
}
let container = match parent.kind {
ModuleKind::Def(Def::Mod(_), _) => "module",
ModuleKind::Def(Def::Trait(_), _) => "trait",
ModuleKind::Block(..) => "block",
_ => "enum",
};
let old_noun = match old_binding.is_import() {
true => "import",
false => "definition",
};
let new_participle = match new_binding.is_import() {
true => "imported",
false => "defined",
};
let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
if let Some(s) = self.name_already_seen.get(&name) {
if s == &span {
return;
}
}
let old_kind = match (ns, old_binding.module()) {
(ValueNS, _) => "value",
(MacroNS, _) => "macro",
(TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
(TypeNS, Some(module)) if module.is_normal() => "module",
(TypeNS, Some(module)) if module.is_trait() => "trait",
(TypeNS, _) => "type",
};
let msg = format!("the name `{}` is defined multiple times", name);
let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
(true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
(true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
true => struct_span_err!(self.session, span, E0254, "{}", msg),
false => struct_span_err!(self.session, span, E0260, "{}", msg),
},
_ => match (old_binding.is_import(), new_binding.is_import()) {
(false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
(true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
_ => struct_span_err!(self.session, span, E0255, "{}", msg),
},
};
err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
name,
ns.descr(),
container));
err.span_label(span, format!("`{}` re{} here", name, new_participle));
if !old_binding.span.is_dummy() {
err.span_label(self.session.source_map().def_span(old_binding.span),
format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
}
// See https://github.com/rust-lang/rust/issues/32354
if old_binding.is_import() || new_binding.is_import() {
let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
new_binding
} else {
old_binding
};
let cm = self.session.source_map();
let rename_msg = "you can use `as` to change the binding name of the import";
if let (
Ok(snippet),
NameBindingKind::Import { directive, ..},
_dummy @ false,
) = (
cm.span_to_snippet(binding.span),
binding.kind.clone(),
binding.span.is_dummy(),
) {
let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
format!("Other{}", name)
} else {
format!("other_{}", name)
};
err.span_suggestion_with_applicability(
binding.span,
&rename_msg,
match directive.subclass {
ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
format!("self as {}", suggested_name),
ImportDirectiveSubclass::SingleImport { source, .. } =>
format!(
"{} as {}{}",
&snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
suggested_name,
if snippet.ends_with(";") {
";"
} else {
""
}
),
ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
format!(
"extern crate {} as {};",
source.unwrap_or(target.name),
suggested_name,
),
_ => unreachable!(),
},
Applicability::MaybeIncorrect,
);
} else {
err.span_label(binding.span, rename_msg);
}
}
err.emit();
self.name_already_seen.insert(name, span);
}
fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
-> Option<&'a NameBinding<'a>> {
if ident.is_path_segment_keyword() {
// Make sure `self`, `super` etc produce an error when passed to here.
return None;
}
self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
if let Some(binding) = entry.extern_crate_item {
Some(binding)
} else {
let crate_id = if !speculative {
self.crate_loader.process_path_extern(ident.name, ident.span)
} else if let Some(crate_id) =
self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
crate_id
} else {
return None;
};
let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
self.populate_module_if_necessary(&crate_root);
Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
.to_name_binding(self.arenas))
}
})
}
}
fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfType.name()
}
fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfValue.name()
}
fn names_to_string(idents: &[Ident]) -> String {
let mut result = String::new();
for (i, ident) in idents.iter()
.filter(|ident| ident.name != keywords::CrateRoot.name())
.enumerate() {
if i > 0 {
result.push_str("::");
}
result.push_str(&ident.as_str());
}
result
}
fn path_names_to_string(path: &Path) -> String {
names_to_string(&path.segments.iter()
.map(|seg| seg.ident)
.collect::<Vec<_>>())
}
/// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
let variant_path = &suggestion.path;
let variant_path_string = path_names_to_string(variant_path);
let path_len = suggestion.path.segments.len();
let enum_path = ast::Path {
span: suggestion.path.span,
segments: suggestion.path.segments[0..path_len - 1].to_vec(),
};
let enum_path_string = path_names_to_string(&enum_path);
(suggestion.path.span, variant_path_string, enum_path_string)
}
/// When an entity with a given name is not available in scope, we search for
/// entities with that name in all crates. This method allows outputting the
/// results of this search in a programmer-friendly way
fn show_candidates(err: &mut DiagnosticBuilder,
// This is `None` if all placement locations are inside expansions
span: Option<Span>,
candidates: &[ImportSuggestion],
better: bool,
found_use: bool) {
// we want consistent results across executions, but candidates are produced
// by iterating through a hash map, so make sure they are ordered:
let mut path_strings: Vec<_> =
candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
path_strings.sort();
let better = if better { "better " } else { "" };
let msg_diff = match path_strings.len() {
1 => " is found in another module, you can import it",
_ => "s are found in other modules, you can import them",
};
let msg = format!("possible {}candidate{} into scope", better, msg_diff);
if let Some(span) = span {
for candidate in &mut path_strings {
// produce an additional newline to separate the new use statement
// from the directly following item.
let additional_newline = if found_use {
""
} else {
"\n"
};
*candidate = format!("use {};\n{}", candidate, additional_newline);
}
err.span_suggestions_with_applicability(
span,
&msg,
path_strings.into_iter(),
Applicability::Unspecified,
);
} else {
let mut msg = msg;
msg.push(':');
for candidate in path_strings {
msg.push('\n');
msg.push_str(&candidate);
}
}
}
/// 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<Ident>, module: Module) {
if let ModuleKind::Def(_, name) = module.kind {
if let Some(parent) = module.parent {
names.push(Ident::with_empty_ctxt(name));
collect_mod(names, parent);
}
} else {
// danger, shouldn't be ident?
names.push(Ident::from_str("<opaque>"));
collect_mod(names, module.parent.unwrap());
}
}
collect_mod(&mut names, module);
if names.is_empty() {
return None;
}
Some(names_to_string(&names.into_iter()
.rev()
.collect::<Vec<_>>()))
}
fn err_path_resolution() -> PathResolution {
PathResolution::new(Def::Err)
}
#[derive(PartialEq,Copy, Clone)]
pub enum MakeGlobMap {
Yes,
No,
}
#[derive(Copy, Clone, Debug)]
enum CrateLint {
/// Do not issue the lint
No,
/// This lint applies to some random path like `impl ::foo::Bar`
/// or whatever. 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),
}
}
}
__build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }