3498 lines
143 KiB
Rust

// 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.
#![crate_name = "rustc_resolve"]
#![unstable(feature = "rustc_private", issue = "27812")]
#![crate_type = "dylib"]
#![crate_type = "rlib"]
#![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/")]
#![deny(warnings)]
#![feature(associated_consts)]
#![feature(rustc_diagnostic_macros)]
#![feature(rustc_private)]
#![feature(staged_api)]
#[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;
use self::Namespace::*;
use self::TypeParameters::*;
use self::RibKind::*;
use rustc::hir::map::{Definitions, DefCollector};
use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
use rustc::middle::cstore::CrateLoader;
use rustc::session::Session;
use rustc::lint;
use rustc::hir::def::*;
use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
use rustc::ty;
use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
use syntax::ext::hygiene::{Mark, SyntaxContext};
use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
use syntax::ext::base::SyntaxExtension;
use syntax::ext::base::Determinacy::{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::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
use syntax::feature_gate::{feature_err, emit_feature_err, GateIssue};
use syntax_pos::{Span, DUMMY_SP, MultiSpan};
use errors::DiagnosticBuilder;
use std::cell::{Cell, RefCell};
use std::cmp;
use std::collections::BTreeSet;
use std::fmt;
use std::mem::replace;
use std::rc::Rc;
use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
// NB: This module needs to be declared first so diagnostics are
// registered before they are used.
mod diagnostics;
mod macros;
mod check_unused;
mod build_reduced_graph;
mod resolve_imports;
/// 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,
/// error E0402: cannot use an outer type parameter in this context
OuterTypeParameterContext,
/// 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),
/// 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 E0432: unresolved import
UnresolvedImport(Option<(&'a str, &'a str)>),
/// 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,
}
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 => {
let mut err = struct_span_err!(resolver.session,
span,
E0401,
"can't use type parameters from outer function; \
try using a local type parameter instead");
err.span_label(span, &format!("use of type variable from outer function"));
err
}
ResolutionError::OuterTypeParameterContext => {
struct_span_err!(resolver.session,
span,
E0402,
"cannot use an outer type parameter in this context")
}
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, &format!("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().map(|x| *x).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, "E0408");
for sp in target_sp {
err.span_label(sp, &format!("pattern doesn't bind `{}`", binding_error.name));
}
let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
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, &format!("bound in different ways"));
err.span_label(first_binding_span, &format!("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, &format!("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, &format!("used in a pattern more than once"));
err
}
ResolutionError::UndeclaredLabel(name) => {
let mut err = struct_span_err!(resolver.session,
span,
E0426,
"use of undeclared label `{}`",
name);
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 => {
struct_span_err!(resolver.session,
span,
E0430,
"`self` import can only appear once in the list")
}
ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
struct_span_err!(resolver.session,
span,
E0431,
"`self` import can only appear in an import list with a \
non-empty prefix")
}
ResolutionError::UnresolvedImport(name) => {
let msg = match name {
Some((n, _)) => format!("unresolved import `{}`", n),
None => "unresolved import".to_owned(),
};
let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
if let Some((_, p)) = name {
err.span_label(span, &p);
}
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 => {
struct_span_err!(resolver.session,
span,
E0434,
"{}",
"can't capture dynamic environment in a fn item; use the || { ... } \
closure form instead")
}
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, &format!("non-constant used with constant"));
err
}
ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
let shadows_what = PathResolution::new(binding.def()).kind_name();
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 a {}", shadows_what));
let participle = if binding.is_import() { "imported" } else { "defined" };
let msg = &format!("a {} `{}` 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, &format!("defaulted type parameters \
cannot be forward declared"));
err
}
}
}
#[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 is_refutable(self) -> bool {
match self {
PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
}
}
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 PathSource<'a> {
// Type paths `Path`.
Type,
// Trait paths in bounds or impls.
Trait,
// 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,
// Path in `use a::b::{...};`
ImportPrefix,
}
impl<'a> PathSource<'a> {
fn namespace(self) -> Namespace {
match self {
PathSource::Type | PathSource::Trait | PathSource::Struct |
PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
PathSource::TraitItem(ns) => ns,
}
}
fn global_by_default(self) -> bool {
match self {
PathSource::Visibility | PathSource::ImportPrefix => 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 | PathSource::ImportPrefix => 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::ImportPrefix => "module or enum",
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::TyAlias(..) | Def::AssociatedTy(..) |
Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
_ => false,
},
PathSource::Trait => match def {
Def::Trait(..) => 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(..) => true,
_ => false,
},
PathSource::Pat => match def {
Def::StructCtor(_, CtorKind::Const) |
Def::VariantCtor(_, CtorKind::Const) |
Def::Const(..) | Def::AssociatedConst(..) => true,
_ => false,
},
PathSource::TupleStruct => match def {
Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => 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::ImportPrefix => match def {
Def::Mod(..) | Def::Enum(..) => 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) | (PathSource::ImportPrefix, true) => "E0577",
(PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
pub enum Namespace {
TypeNS,
ValueNS,
MacroNS,
}
#[derive(Clone, Default, Debug)]
pub struct PerNS<T> {
value_ns: T,
type_ns: T,
macro_ns: Option<T>,
}
impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
type Output = T;
fn index(&self, ns: Namespace) -> &T {
match ns {
ValueNS => &self.value_ns,
TypeNS => &self.type_ns,
MacroNS => self.macro_ns.as_ref().unwrap(),
}
}
}
impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
fn index_mut(&mut self, ns: Namespace) -> &mut T {
match ns {
ValueNS => &mut self.value_ns,
TypeNS => &mut self.type_ns,
MacroNS => self.macro_ns.as_mut().unwrap(),
}
}
}
impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
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_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) {
if let TyKind::Path(ref qself, ref path) = ty.node {
self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
} else if let TyKind::ImplicitSelf = ty.node {
let self_ty = keywords::SelfType.ident();
let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.span))
.map_or(Def::Err, |d| d.def());
self.record_def(ty.id, PathResolution::new(def));
} else if let TyKind::Array(ref element, ref length) = ty.node {
self.visit_ty(element);
self.with_constant_rib(|this| {
this.visit_expr(length);
});
return;
}
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);
visit::walk_poly_trait_ref(self, tref, m);
}
fn visit_variant(&mut self,
variant: &'tcx ast::Variant,
generics: &'tcx Generics,
item_id: ast::NodeId) {
if let Some(ref dis_expr) = variant.node.disr_expr {
// resolve the discriminator expr as a constant
self.with_constant_rib(|this| {
this.visit_expr(dis_expr);
});
}
// `visit::walk_variant` without the discriminant expression.
self.visit_variant_data(&variant.node.data,
variant.node.name,
generics,
item_id,
variant.span);
}
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,
};
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 = match function_kind {
FnKind::ItemFn(_, generics, ..) => {
self.visit_generics(generics);
ItemRibKind
}
FnKind::Method(_, sig, _, _) => {
self.visit_generics(&sig.generics);
MethodRibKind(!sig.decl.has_self())
}
FnKind::Closure(_) => ClosureRibKind(node_id),
};
// 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();
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.
match function_kind {
FnKind::ItemFn(.., body) |
FnKind::Method(.., body) => {
self.visit_block(body);
}
FnKind::Closure(body) => {
self.visit_expr(body);
}
};
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.
let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
default_ban_rib.bindings.extend(generics.ty_params.iter()
.skip_while(|p| p.default.is_none())
.map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
for param in &generics.ty_params {
for bound in &param.bounds {
self.visit_ty_param_bound(bound);
}
if let Some(ref ty) = param.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 lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
}
}
pub type ErrorMessage = Option<(Span, String)>;
#[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. Allow references to ty params that impl or trait
// binds. Disallow any other upvars (including other ty params that are
// upvars).
//
// The boolean value represents the fact that this method is static or not.
MethodRibKind(bool),
// 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.
#[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: FxHashMap(),
kind: kind,
}
}
}
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(Clone)]
enum PathResult<'a> {
Module(Module<'a>),
NonModule(PathResolution),
Indeterminate,
Failed(String, bool /* is the error from the last segment? */),
}
enum ModuleKind {
Block(NodeId),
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>>>>,
legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
// 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>,
}
pub type Module<'a> = &'a ModuleData<'a>;
impl<'a> ModuleData<'a> {
fn new(parent: Option<Module<'a>>, kind: ModuleKind, normal_ancestor_id: DefId) -> Self {
ModuleData {
parent: parent,
kind: kind,
normal_ancestor_id: normal_ancestor_id,
resolutions: RefCell::new(FxHashMap()),
legacy_macro_resolutions: RefCell::new(Vec::new()),
macro_resolutions: RefCell::new(Vec::new()),
unresolved_invocations: RefCell::new(FxHashSet()),
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()),
}
}
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 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 }
}
}
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),
Module(Module<'a>),
Import {
binding: &'a NameBinding<'a>,
directive: &'a ImportDirective<'a>,
used: Cell<bool>,
legacy_self_import: bool,
},
Ambiguity {
b1: &'a NameBinding<'a>,
b2: &'a NameBinding<'a>,
legacy: bool,
}
}
struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
struct AmbiguityError<'a> {
span: Span,
name: Name,
lexical: bool,
b1: &'a NameBinding<'a>,
b2: &'a NameBinding<'a>,
legacy: bool,
}
impl<'a> NameBinding<'a> {
fn module(&self) -> Option<Module<'a>> {
match self.kind {
NameBindingKind::Module(module) => Some(module),
NameBindingKind::Import { binding, .. } => binding.module(),
NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.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 { legacy: true, b1, .. } => b1.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(),
}
}
fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc<SyntaxExtension> {
resolver.get_macro(self.def_ignoring_ambiguity())
}
// We sometimes need to treat variants as `pub` for backwards compatibility
fn pseudo_vis(&self) -> ty::Visibility {
if self.is_variant() { 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,
_ => 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,
}
}
}
/// Interns the names of the primitive types.
struct PrimitiveTypeTable {
primitive_types: FxHashMap<Name, PrimTy>,
}
impl PrimitiveTypeTable {
fn new() -> PrimitiveTypeTable {
let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
table.intern("bool", TyBool);
table.intern("char", TyChar);
table.intern("f32", TyFloat(FloatTy::F32));
table.intern("f64", TyFloat(FloatTy::F64));
table.intern("isize", TyInt(IntTy::Is));
table.intern("i8", TyInt(IntTy::I8));
table.intern("i16", TyInt(IntTy::I16));
table.intern("i32", TyInt(IntTy::I32));
table.intern("i64", TyInt(IntTy::I64));
table.intern("i128", TyInt(IntTy::I128));
table.intern("str", TyStr);
table.intern("usize", TyUint(UintTy::Us));
table.intern("u8", TyUint(UintTy::U8));
table.intern("u16", TyUint(UintTy::U16));
table.intern("u32", TyUint(UintTy::U32));
table.intern("u64", TyUint(UintTy::U64));
table.intern("u128", TyUint(UintTy::U128));
table
}
fn intern(&mut self, string: &str, primitive_type: PrimTy) {
self.primitive_types.insert(Symbol::intern(string), primitive_type);
}
}
/// The main resolver class.
pub struct Resolver<'a> {
session: &'a Session,
pub definitions: Definitions,
graph_root: Module<'a>,
prelude: Option<Module<'a>>,
trait_item_map: FxHashMap<(DefId, Name, Namespace), (Def, bool /* has self */)>,
// 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<(DefId, TraitRef)>,
// The current self type if inside an impl (used for better errors).
current_self_type: Option<Ty>,
// The idents for the primitive types.
primitive_type_table: PrimitiveTypeTable,
def_map: DefMap,
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_crate_roots: FxHashMap<(CrateNum, bool /* MacrosOnly? */), 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,
privacy_errors: Vec<PrivacyError<'a>>,
ambiguity_errors: Vec<AmbiguityError<'a>>,
gated_errors: FxHashSet<Span>,
disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
arenas: &'a ResolverArenas<'a>,
dummy_binding: &'a NameBinding<'a>,
use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
crate_loader: &'a mut CrateLoader,
macro_names: FxHashSet<Name>,
global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
lexical_macro_resolutions: Vec<(Name, &'a Cell<LegacyScope<'a>>)>,
macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
macro_defs: FxHashMap<Mark, DefId>,
local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
macro_exports: Vec<Export>,
pub whitelisted_legacy_custom_derives: Vec<Name>,
pub found_unresolved_macro: bool,
// 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>,
// If `#![feature(proc_macro)]` is set
proc_macro_enabled: bool,
// A set of procedural macros imported by `#[macro_use]` that have already been warned about
warned_proc_macros: FxHashSet<Name>,
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)>,
}
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> ty::DefIdTree for &'a Resolver<'b> {
fn parent(self, id: DefId) -> Option<DefId> {
match id.krate {
LOCAL_CRATE => self.definitions.def_key(id.index).parent,
_ => self.session.cstore.def_key(id).parent,
}.map(|index| DefId { index: index, ..id })
}
}
impl<'a> hir::lowering::Resolver for Resolver<'a> {
fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
let namespace = if is_value { ValueNS } else { TypeNS };
let hir::Path { ref segments, span, ref mut def } = *path;
let path: Vec<_> = segments.iter().map(|seg| Ident::with_empty_ctxt(seg.name)).collect();
match self.resolve_path(&path, Some(namespace), Some(span)) {
PathResult::Module(module) => *def = module.def().unwrap(),
PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
*def = path_res.base_def(),
PathResult::NonModule(..) => match self.resolve_path(&path, None, Some(span)) {
PathResult::Failed(msg, _) => {
resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
}
_ => {}
},
PathResult::Indeterminate => unreachable!(),
PathResult::Failed(msg, _) => {
resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
}
}
}
fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
self.def_map.get(&id).cloned()
}
fn definitions(&mut self) -> &mut Definitions {
&mut self.definitions
}
}
impl<'a> Resolver<'a> {
pub fn new(session: &'a Session,
krate: &Crate,
make_glob_map: MakeGlobMap,
crate_loader: &'a mut CrateLoader,
arenas: &'a ResolverArenas<'a>)
-> Resolver<'a> {
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)
});
let mut module_map = FxHashMap();
module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
let mut definitions = Definitions::new();
DefCollector::new(&mut definitions).collect_root();
let mut invocations = FxHashMap();
invocations.insert(Mark::root(),
arenas.alloc_invocation_data(InvocationData::root(graph_root)));
let features = session.features.borrow();
let mut macro_defs = FxHashMap();
macro_defs.insert(Mark::root(), root_def_id);
Resolver {
session: session,
definitions: definitions,
// The outermost module has def ID 0; this is not reflected in the
// AST.
graph_root: graph_root,
prelude: None,
trait_item_map: FxHashMap(),
field_names: FxHashMap(),
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: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
},
label_ribs: Vec::new(),
current_trait_ref: None,
current_self_type: None,
primitive_type_table: PrimitiveTypeTable::new(),
def_map: NodeMap(),
freevars: NodeMap(),
freevars_seen: NodeMap(),
export_map: NodeMap(),
trait_map: NodeMap(),
module_map: module_map,
block_map: NodeMap(),
extern_crate_roots: FxHashMap(),
make_glob_map: make_glob_map == MakeGlobMap::Yes,
glob_map: NodeMap(),
used_imports: FxHashSet(),
maybe_unused_trait_imports: NodeSet(),
privacy_errors: Vec::new(),
ambiguity_errors: Vec::new(),
gated_errors: FxHashSet(),
disallowed_shadowing: Vec::new(),
arenas: arenas,
dummy_binding: arenas.alloc_name_binding(NameBinding {
kind: NameBindingKind::Def(Def::Err),
expansion: Mark::root(),
span: DUMMY_SP,
vis: ty::Visibility::Public,
}),
// `#![feature(proc_macro)]` implies `#[feature(extern_macros)]`
use_extern_macros: features.use_extern_macros || features.proc_macro,
crate_loader: crate_loader,
macro_names: FxHashSet(),
global_macros: FxHashMap(),
lexical_macro_resolutions: Vec::new(),
macro_map: FxHashMap(),
macro_exports: Vec::new(),
invocations: invocations,
macro_defs: macro_defs,
local_macro_def_scopes: FxHashMap(),
name_already_seen: FxHashMap(),
whitelisted_legacy_custom_derives: Vec::new(),
proc_macro_enabled: features.proc_macro,
warned_proc_macros: FxHashSet(),
potentially_unused_imports: Vec::new(),
struct_constructors: DefIdMap(),
found_unresolved_macro: false,
}
}
pub fn arenas() -> ResolverArenas<'a> {
ResolverArenas {
modules: arena::TypedArena::new(),
local_modules: RefCell::new(Vec::new()),
name_bindings: arena::TypedArena::new(),
import_directives: arena::TypedArena::new(),
name_resolutions: arena::TypedArena::new(),
invocation_data: arena::TypedArena::new(),
legacy_bindings: arena::TypedArena::new(),
}
}
fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
PerNS {
type_ns: f(self, TypeNS),
value_ns: f(self, ValueNS),
macro_ns: match self.use_extern_macros {
true => Some(f(self, MacroNS)),
false => None,
},
}
}
/// 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();
self.crate_loader.postprocess(krate);
}
fn new_module(&self, parent: Module<'a>, kind: ModuleKind, normal_ancestor_id: DefId)
-> Module<'a> {
self.arenas.alloc_module(ModuleData::new(Some(parent), kind, normal_ancestor_id))
}
fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
-> bool /* true if an error was reported */ {
match binding.kind {
NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
if !used.get() => {
used.set(true);
directive.used.set(true);
if legacy_self_import {
self.warn_legacy_self_import(directive);
return false;
}
self.used_imports.insert((directive.id, ns));
self.add_to_glob_map(directive.id, ident);
self.record_use(ident, ns, binding, span)
}
NameBindingKind::Import { .. } => false,
NameBindingKind::Ambiguity { b1, b2, legacy } => {
self.ambiguity_errors.push(AmbiguityError {
span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy: legacy,
});
if legacy {
self.record_use(ident, ns, b1, span);
}
!legacy
}
_ => false
}
}
fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
if self.make_glob_map {
self.glob_map.entry(id).or_insert_with(FxHashSet).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: Option<Span>)
-> Option<LexicalScopeBinding<'a>> {
if ns == TypeNS {
ident = ident.unhygienize();
}
// Walk backwards up the ribs in scope.
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)
));
}
if let ModuleRibKind(module) = self.ribs[ns][i].kind {
let item = self.resolve_ident_in_module(module, ident, ns, false, record_used);
if let Ok(binding) = item {
// The ident resolves to an item.
return Some(LexicalScopeBinding::Item(binding));
}
if let ModuleKind::Block(..) = module.kind { // We can see through blocks
} else if !module.no_implicit_prelude {
return self.prelude.and_then(|prelude| {
self.resolve_ident_in_module(prelude, ident, ns, false, None).ok()
}).map(LexicalScopeBinding::Item)
} else {
return None;
}
}
if let MacroDefinition(def) = self.ribs[ns][i].kind {
// If an invocation of this macro created `ident`, give up on `ident`
// and switch to `ident`'s source from the macro definition.
let ctxt_data = ident.ctxt.data();
if def == self.macro_defs[&ctxt_data.outer_mark] {
ident.ctxt = ctxt_data.prev_ctxt;
}
}
}
None
}
fn resolve_crate_var(&mut self, crate_var_ctxt: SyntaxContext) -> Module<'a> {
let mut ctxt_data = crate_var_ctxt.data();
while ctxt_data.prev_ctxt != SyntaxContext::empty() {
ctxt_data = ctxt_data.prev_ctxt.data();
}
let module = self.macro_def_scope(ctxt_data.outer_mark);
if module.is_local() { self.graph_root } else { 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.
fn with_scope<F>(&mut self, id: NodeId, f: F)
where F: FnOnce(&mut Resolver)
{
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();
f(self);
self.current_module = orig_module;
self.ribs[ValueNS].pop();
self.ribs[TypeNS].pop();
} else {
f(self);
}
}
/// Searches the current set of local scopes for labels.
/// Stops after meeting a closure.
fn search_label(&self, mut ident: Ident) -> Option<Def> {
for rib in self.label_ribs.iter().rev() {
match rib.kind {
NormalRibKind => {
// Continue
}
MacroDefinition(def) => {
// If an invocation of this macro created `ident`, give up on `ident`
// and switch to `ident`'s source from the macro definition.
let ctxt_data = ident.ctxt.data();
if def == self.macro_defs[&ctxt_data.outer_mark] {
ident.ctxt = ctxt_data.prev_ctxt;
}
}
_ => {
// Do not resolve labels across function boundary
return None;
}
}
let result = rib.bindings.get(&ident).cloned();
if result.is_some() {
return result;
}
}
None
}
fn resolve_item(&mut self, item: &Item) {
let name = item.ident.name;
debug!("(resolving item) resolving {}", name);
self.check_proc_macro_attrs(&item.attrs);
match item.node {
ItemKind::Enum(_, ref generics) |
ItemKind::Ty(_, ref generics) |
ItemKind::Struct(_, ref generics) |
ItemKind::Union(_, ref generics) |
ItemKind::Fn(.., ref generics, _) => {
self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
|this| visit::walk_item(this, item));
}
ItemKind::DefaultImpl(_, ref trait_ref) => {
self.with_optional_trait_ref(Some(trait_ref), |this, _| {
// Resolve type arguments in trait path
visit::walk_trait_ref(this, trait_ref);
});
}
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_ty_param_bound, bounds);
for trait_item in trait_items {
this.check_proc_macro_attrs(&trait_item.attrs);
match trait_item.node {
TraitItemKind::Const(_, ref default) => {
// Only impose the restrictions of
// ConstRibKind if there's an actual constant
// expression in a provided default.
if default.is_some() {
this.with_constant_rib(|this| {
visit::walk_trait_item(this, trait_item)
});
} else {
visit::walk_trait_item(this, trait_item)
}
}
TraitItemKind::Method(ref sig, _) => {
let type_parameters =
HasTypeParameters(&sig.generics,
MethodRibKind(!sig.decl.has_self()));
this.with_type_parameter_rib(type_parameters, |this| {
visit::walk_trait_item(this, trait_item)
});
}
TraitItemKind::Type(..) => {
this.with_type_parameter_rib(NoTypeParameters, |this| {
visit::walk_trait_item(this, trait_item)
});
}
TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
};
}
});
});
}
ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
self.with_scope(item.id, |this| {
visit::walk_item(this, item);
});
}
ItemKind::Const(..) | ItemKind::Static(..) => {
self.with_constant_rib(|this| {
visit::walk_item(this, item);
});
}
ItemKind::Use(ref view_path) => {
match view_path.node {
ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
// Resolve prefix of an import with empty braces (issue #28388).
self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
}
_ => {}
}
}
ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) => {
// 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();
for type_parameter in &generics.ty_params {
let name = type_parameter.ident.name;
debug!("with_type_parameter_rib: {}", type_parameter.id);
if seen_bindings.contains_key(&name) {
let span = seen_bindings.get(&name).unwrap();
resolve_error(self,
type_parameter.span,
ResolutionError::NameAlreadyUsedInTypeParameterList(name,
span));
}
seen_bindings.entry(name).or_insert(type_parameter.span);
// plain insert (no renaming)
let def_id = self.definitions.local_def_id(type_parameter.id);
let def = Def::TyParam(def_id);
function_type_rib.bindings.insert(Ident::with_empty_ctxt(name), def);
self.record_def(type_parameter.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_constant_rib<F>(&mut self, f: F)
where F: FnOnce(&mut Resolver)
{
self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
self.ribs[TypeNS].push(Rib::new(ConstantItemRibKind));
f(self);
self.ribs[TypeNS].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_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 def = self.smart_resolve_path(trait_ref.ref_id, None,
&trait_ref.path, PathSource::Trait).base_def();
if def != Def::Err {
new_val = Some((def.def_id(), trait_ref.clone()));
new_id = Some(def.def_id());
}
}
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 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 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);
this.with_current_self_type(self_type, |this| {
for impl_item in impl_items {
this.check_proc_macro_attrs(&impl_item.attrs);
this.resolve_visibility(&impl_item.vis);
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.name,
ValueNS,
impl_item.span,
|n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
visit::walk_impl_item(this, impl_item);
}
ImplItemKind::Method(ref sig, _) => {
// If this is a trait impl, ensure the method
// exists in trait
this.check_trait_item(impl_item.ident.name,
ValueNS,
impl_item.span,
|n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
// We also need a new scope for the method-
// specific type parameters.
let type_parameters =
HasTypeParameters(&sig.generics,
MethodRibKind(!sig.decl.has_self()));
this.with_type_parameter_rib(type_parameters, |this| {
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.name,
TypeNS,
impl_item.span,
|n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
this.visit_ty(ty);
}
ImplItemKind::Macro(_) =>
panic!("unexpanded macro in resolve!"),
}
}
});
});
});
});
});
}
fn check_trait_item<F>(&self, name: Name, 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((did, ref trait_ref)) = self.current_trait_ref {
if !self.trait_item_map.contains_key(&(did, name, ns)) {
let path_str = path_names_to_string(&trait_ref.path);
resolve_error(self, span, err(name, &path_str));
}
}
}
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());
}
// 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();
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.node, 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, arm: &Arm) {
if arm.pats.is_empty() {
return;
}
let mut missing_vars = FxHashMap();
let mut inconsistent_vars = FxHashMap();
for (i, p) in arm.pats.iter().enumerate() {
let map_i = self.binding_mode_map(&p);
for (j, q) in arm.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.len() == 0 { // 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();
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);
walk_list!(self, visit_expr, &arm.guard);
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 let Some(_) = anonymous_module {
self.ribs[TypeNS].pop();
}
debug!("(resolving block) leaving block");
}
fn fresh_binding(&mut self,
ident: &SpannedIdent,
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 mut def = Def::Local(self.definitions.local_def_id(pat_id));
match bindings.get(&ident.node).cloned() {
Some(id) if id == outer_pat_id => {
// `Variant(a, a)`, error
resolve_error(
self,
ident.span,
ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
&ident.node.name.as_str())
);
}
Some(..) if pat_src == PatternSource::FnParam => {
// `fn f(a: u8, a: u8)`, error
resolve_error(
self,
ident.span,
ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
&ident.node.name.as_str())
);
}
Some(..) if pat_src == PatternSource::Match => {
// `Variant1(a) | Variant2(a)`, ok
// Reuse definition from the first `a`.
def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
}
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.node.name != keywords::Invalid.name() {
bindings.insert(ident.node, outer_pat_id);
self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, 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, ref 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.node, ValueNS, None)
.and_then(LexicalScopeBinding::item);
let resolution = binding.map(NameBinding::def).and_then(|def| {
let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
bmode != BindingMode::ByValue(Mutability::Immutable);
match def {
Def::StructCtor(_, CtorKind::Const) |
Def::VariantCtor(_, CtorKind::Const) |
Def::Const(..) if !always_binding => {
// A unit struct/variant or constant pattern.
self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
Some(PathResolution::new(def))
}
Def::StructCtor(..) | Def::VariantCtor(..) |
Def::Const(..) | Def::Static(..) => {
// A fresh binding that shadows something unacceptable.
resolve_error(
self,
ident.span,
ResolutionError::BindingShadowsSomethingUnacceptable(
pat_src.descr(), ident.node.name, binding.unwrap())
);
None
}
Def::Local(..) | Def::Upvar(..) | 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 {
let segments = &path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>();
let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
}
fn smart_resolve_path_fragment(&mut self,
id: NodeId,
qself: Option<&QSelf>,
path: &[Ident],
span: Span,
ident_span: Span,
source: PathSource)
-> PathResolution {
let ns = source.namespace();
let is_expected = &|def| source.is_expected(def);
// 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 = names_to_string(path);
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_str = path[path.len() - 1];
let (mod_prefix, mod_str) = if path.len() == 1 {
(format!(""), format!("this scope"))
} else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
(format!(""), format!("the crate root"))
} else {
let mod_path = &path[..path.len() - 1];
let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), None) {
PathResult::Module(module) => module.def(),
_ => None,
}.map_or(format!(""), |def| format!("{} ", def.kind_name()));
(mod_prefix, format!("`{}`", names_to_string(mod_path)))
};
(format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
format!("not found in {}", mod_str), ident_span)
};
let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
// Emit special messages for unresolved `Self` and `self`.
if is_self_type(path, ns) {
__diagnostic_used!(E0411);
err.code("E0411".into());
err.span_label(span, &format!("`Self` is only available in traits and impls"));
return err;
}
if is_self_value(path, ns) {
__diagnostic_used!(E0424);
err.code("E0424".into());
err.span_label(span, &format!("`self` value is only available in \
methods with `self` parameter"));
return err;
}
// Try to lookup the name in more relaxed fashion for better error reporting.
let name = path.last().unwrap().name;
let candidates = this.lookup_import_candidates(name, ns, is_expected);
if !candidates.is_empty() {
// Report import candidates as help and proceed searching for labels.
show_candidates(&mut err, &candidates, def.is_some());
}
if path.len() == 1 && this.self_type_is_available() {
if let Some(candidate) = this.lookup_assoc_candidate(name, ns, is_expected) {
let self_is_available = this.self_value_is_available(path[0].ctxt);
match candidate {
AssocSuggestion::Field => {
err.span_label(span, &format!("did you mean `self.{}`?", path_str));
if !self_is_available {
err.span_label(span, &format!("`self` value is only available in \
methods with `self` parameter"));
}
}
AssocSuggestion::MethodWithSelf if self_is_available => {
err.span_label(span, &format!("did you mean `self.{}(...)`?",
path_str));
}
AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
err.span_label(span, &format!("did you mean `Self::{}`?", path_str));
}
}
return err;
}
}
// 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;
}
(Def::TyAlias(..), PathSource::Trait) => {
err.span_label(span, &format!("type aliases cannot be used for traits"));
return err;
}
(Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
ExprKind::Field(_, ident) => {
err.span_label(parent.span, &format!("did you mean `{}::{}`?",
path_str, ident.node));
return err;
}
ExprKind::MethodCall(ident, ..) => {
err.span_label(parent.span, &format!("did you mean `{}::{}(...)`?",
path_str, ident.node));
return err;
}
_ => {}
},
_ if ns == ValueNS && is_struct_like(def) => {
if let Def::Struct(def_id) = def {
if let Some((ctor_def, ctor_vis))
= this.struct_constructors.get(&def_id).cloned() {
if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
err.span_label(span, &format!("constructor is not visible \
here due to private fields"));
}
}
}
err.span_label(span, &format!("did you mean `{} {{ /* fields */ }}`?",
path_str));
return err;
}
_ => {}
}
}
// Try Levenshtein if nothing else worked.
if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected) {
err.span_label(ident_span, &format!("did you mean `{}`?", candidate));
return err;
}
// Fallback label.
err.span_label(base_span, &fallback_label);
err
};
let report_errors = |this: &mut Self, def: Option<Def>| {
report_errors(this, def).emit();
err_path_resolution()
};
let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
source.defer_to_typeck(),
source.global_by_default()) {
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.add_lint(lint, id, span,
"private struct constructors are not usable through \
reexports in outer modules".to_string());
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().name;
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 self_type_is_available(&mut self) -> bool {
let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(), TypeNS, None);
if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
}
fn self_value_is_available(&mut self, ctxt: SyntaxContext) -> bool {
let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None);
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: &[Ident],
primary_ns: Namespace,
span: Span,
defer_to_typeck: bool,
global_by_default: bool)
-> 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) {
// 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 },
};
}
}
let is_global = self.global_macros.get(&path[0].name).cloned()
.map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
if primary_ns != MacroNS && (is_global || self.macro_names.contains(&path[0].name)) {
// 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: &[Ident],
ns: Namespace,
span: Span,
global_by_default: bool)
-> Option<PathResolution> {
if let Some(qself) = qself {
if qself.position == 0 {
// FIXME: Create some fake resolution that can't possibly be a type.
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.
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, span, PathSource::TraitItem(ns));
return Some(PathResolution::with_unresolved_segments(
res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
));
}
let result = match self.resolve_path(&path, Some(ns), Some(span)) {
PathResult::NonModule(path_res) => path_res,
PathResult::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(..) | PathResult::Failed(..)
if (ns == TypeNS || path.len() > 1) &&
self.primitive_type_table.primitive_types.contains_key(&path[0].name) => {
let prim = self.primitive_type_table.primitive_types[&path[0].name];
match prim {
TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
if !self.session.features.borrow().i128_type {
emit_feature_err(&self.session.parse_sess,
"i128_type", span, GateIssue::Language,
"128-bit type is unstable");
}
}
_ => {}
}
PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
}
PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
PathResult::Failed(msg, false) => {
resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
err_path_resolution()
}
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].name != keywords::CrateRoot.name() && path[0].name != "$crate" {
let unqualified_result = {
match self.resolve_path(&[*path.last().unwrap()], Some(ns), None) {
PathResult::NonModule(path_res) => path_res.base_def(),
PathResult::Module(module) => module.def().unwrap(),
_ => return Some(result),
}
};
if result.base_def() == unqualified_result {
let lint = lint::builtin::UNUSED_QUALIFICATIONS;
self.session.add_lint(lint, id, span, "unnecessary qualification".to_string());
}
}
Some(result)
}
fn resolve_path(&mut self,
path: &[Ident],
opt_ns: Option<Namespace>, // `None` indicates a module path
record_used: Option<Span>)
-> PathResult<'a> {
let mut module = None;
let mut allow_super = true;
for (i, &ident) in path.iter().enumerate() {
let is_last = i == path.len() - 1;
let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
if i == 0 && ns == TypeNS && ident.name == keywords::SelfValue.name() {
module = Some(self.module_map[&self.current_module.normal_ancestor_id]);
continue
} else if allow_super && ns == TypeNS && ident.name == keywords::Super.name() {
let current_module = if i == 0 { self.current_module } else { module.unwrap() };
let self_module = self.module_map[&current_module.normal_ancestor_id];
if let Some(parent) = self_module.parent {
module = Some(self.module_map[&parent.normal_ancestor_id]);
continue
} else {
let msg = "There are too many initial `super`s.".to_string();
return PathResult::Failed(msg, false);
}
}
allow_super = false;
if i == 0 && ns == TypeNS && ident.name == keywords::CrateRoot.name() {
module = Some(self.graph_root);
continue
} else if i == 0 && ns == TypeNS && ident.name == "$crate" {
module = Some(self.resolve_crate_var(ident.ctxt));
continue
}
let binding = if let Some(module) = module {
self.resolve_ident_in_module(module, ident, ns, false, record_used)
} else if opt_ns == Some(MacroNS) {
self.resolve_lexical_macro_path_segment(ident, ns, record_used)
.map(MacroBinding::binding)
} else {
match self.resolve_ident_in_lexical_scope(ident, ns, record_used) {
Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
Some(LexicalScopeBinding::Def(def))
if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
return PathResult::NonModule(PathResolution::with_unresolved_segments(
def, path.len() - 1
));
}
_ => Err(if record_used.is_some() { Determined } else { Undetermined }),
}
};
match binding {
Ok(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(next_module);
} else if def == Def::Err {
return PathResult::NonModule(err_path_resolution());
} else if opt_ns.is_some() && (is_last || maybe_assoc) {
return PathResult::NonModule(PathResolution::with_unresolved_segments(
def, path.len() - i - 1
));
} else {
return PathResult::Failed(format!("Not a module `{}`", ident), is_last);
}
}
Err(Undetermined) => return PathResult::Indeterminate,
Err(Determined) => {
if let Some(module) = module {
if opt_ns.is_some() && !module.is_normal() {
return PathResult::NonModule(PathResolution::with_unresolved_segments(
module.def().unwrap(), path.len() - i
));
}
}
let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
let mut candidates =
self.lookup_import_candidates(ident.name, TypeNS, is_mod);
candidates.sort_by_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])
};
return PathResult::Failed(msg, is_last);
}
}
}
PathResult::Module(module.unwrap_or(self.graph_root))
}
// Resolve a local definition, potentially adjusting for closures.
fn adjust_local_def(&mut self,
ns: Namespace,
rib_index: usize,
mut def: Def,
record_used: Option<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 let Some(span) = record_used {
resolve_error(self, span,
ResolutionError::ForwardDeclaredTyParam);
}
assert_eq!(def, Def::Err);
return Def::Err;
}
match def {
Def::Upvar(..) => {
span_bug!(record_used.unwrap_or(DUMMY_SP), "unexpected {:?} in bindings", def)
}
Def::Local(def_id) => {
for rib in ribs {
match rib.kind {
NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
ForwardTyParamBanRibKind => {
// Nothing to do. Continue.
}
ClosureRibKind(function_id) => {
let prev_def = def;
let node_id = self.definitions.as_local_node_id(def_id).unwrap();
let seen = self.freevars_seen
.entry(function_id)
.or_insert_with(|| NodeMap());
if let Some(&index) = seen.get(&node_id) {
def = Def::Upvar(def_id, index, function_id);
continue;
}
let vec = self.freevars
.entry(function_id)
.or_insert_with(|| vec![]);
let depth = vec.len();
def = Def::Upvar(def_id, depth, function_id);
if let Some(span) = record_used {
vec.push(Freevar {
def: prev_def,
span: span,
});
seen.insert(node_id, depth);
}
}
ItemRibKind | MethodRibKind(_) => {
// This was an attempt to access an upvar inside a
// named function item. This is not allowed, so we
// report an error.
if let Some(span) = record_used {
resolve_error(self, span,
ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
}
return Def::Err;
}
ConstantItemRibKind => {
// Still doesn't deal with upvars
if let Some(span) = record_used {
resolve_error(self, span,
ResolutionError::AttemptToUseNonConstantValueInConstant);
}
return Def::Err;
}
}
}
}
Def::TyParam(..) | Def::SelfTy(..) => {
for rib in ribs {
match rib.kind {
NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind => {
// Nothing to do. Continue.
}
ItemRibKind => {
// This was an attempt to use a type parameter outside
// its scope.
if let Some(span) = record_used {
resolve_error(self, span,
ResolutionError::TypeParametersFromOuterFunction);
}
return Def::Err;
}
ConstantItemRibKind => {
// see #9186
if let Some(span) = record_used {
resolve_error(self, span,
ResolutionError::OuterTypeParameterContext);
}
return Def::Err;
}
}
}
}
_ => {}
}
return def;
}
// Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope,
// i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`).
// FIXME #34673: This needs testing.
pub fn with_module_lexical_scope<T, F>(&mut self, module: Module<'a>, f: F) -> T
where F: FnOnce(&mut Resolver<'a>) -> T,
{
self.with_empty_ribs(|this| {
this.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
this.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
f(this)
})
}
fn with_empty_ribs<T, F>(&mut self, f: F) -> T
where F: FnOnce(&mut Resolver<'a>) -> T,
{
let ribs = replace(&mut self.ribs, PerNS::<Vec<Rib>>::default());
let label_ribs = replace(&mut self.label_ribs, Vec::new());
let result = f(self);
self.ribs = ribs;
self.label_ribs = label_ribs;
result
}
fn lookup_assoc_candidate<FilterFn>(&mut self,
name: Name,
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(DefId::local(CRATE_DEF_INDEX))) {
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| name == field_name) {
return Some(AssocSuggestion::Field);
}
}
}
_ => {}
}
}
}
}
// Look for associated items in the current trait.
if let Some((trait_did, _)) = self.current_trait_ref {
if let Some(&(def, has_self)) = self.trait_item_map.get(&(trait_did, name, ns)) {
if filter_fn(def) {
return Some(if has_self {
AssocSuggestion::MethodWithSelf
} else {
AssocSuggestion::AssocItem
});
}
}
}
None
}
fn lookup_typo_candidate<FilterFn>(&mut self,
path: &[Ident],
ns: Namespace,
filter_fn: FilterFn)
-> 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 let Some(prelude) = self.prelude {
if !module.no_implicit_prelude {
add_module_candidates(prelude, &mut names);
}
}
break;
}
}
}
// Add primitive types to the mix
if filter_fn(Def::PrimTy(TyBool)) {
for (name, _) in &self.primitive_type_table.primitive_types {
names.push(*name);
}
}
} else {
// Search in module.
let mod_path = &path[..path.len() - 1];
if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS), None) {
add_module_candidates(module, &mut names);
}
}
let name = path[path.len() - 1].name;
// Make sure error reporting is deterministic.
names.sort_by_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<SpannedIdent>, id: NodeId, f: F)
where F: FnOnce(&mut Resolver)
{
if let Some(label) = label {
let def = Def::Label(id);
self.with_label_rib(|this| {
this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
f(this);
});
} else {
f(self);
}
}
fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, 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)) => {
match self.search_label(label.node) {
None => {
self.record_def(expr.id, err_path_resolution());
resolve_error(self,
label.span,
ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
}
Some(def @ Def::Label(_)) => {
// Since this def is a label, it is never read.
self.record_def(expr.id, PathResolution::new(def));
}
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 pattern, ref subexpression, ref if_block, ref optional_else) => {
self.visit_expr(subexpression);
self.ribs[ValueNS].push(Rib::new(NormalRibKind));
self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
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 pattern, ref subexpression, ref block, label) => {
self.with_resolved_label(label, expr.id, |this| {
this.visit_expr(subexpression);
this.ribs[ValueNS].push(Rib::new(NormalRibKind));
this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
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());
self.resolve_labeled_block(label, expr.id, block);
self.ribs[ValueNS].pop();
}
// Equivalent to `visit::walk_expr` + passing some context to children.
ExprKind::Field(ref subexpression, _) => {
self.resolve_expr(subexpression, Some(expr));
}
ExprKind::MethodCall(_, ref types, ref arguments) => {
let mut arguments = arguments.iter();
self.resolve_expr(arguments.next().unwrap(), Some(expr));
for argument in arguments {
self.resolve_expr(argument, None);
}
for ty in types.iter() {
self.visit_ty(ty);
}
}
ExprKind::Repeat(ref element, ref count) => {
self.visit_expr(element);
self.with_constant_rib(|this| {
this.visit_expr(count);
});
}
ExprKind::Call(ref callee, ref arguments) => {
self.resolve_expr(callee, Some(expr));
for argument in arguments {
self.resolve_expr(argument, None);
}
}
_ => {
visit::walk_expr(self, expr);
}
}
}
fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
match expr.node {
ExprKind::Field(_, name) => {
// 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(name.node.name, ValueNS);
self.trait_map.insert(expr.id, traits);
}
ExprKind::MethodCall(name, ..) => {
debug!("(recording candidate traits for expr) recording traits for {}",
expr.id);
let traits = self.get_traits_containing_item(name.node.name, ValueNS);
self.trait_map.insert(expr.id, traits);
}
_ => {
// Nothing to do.
}
}
}
fn get_traits_containing_item(&mut self, name: Name, ns: Namespace) -> Vec<TraitCandidate> {
debug!("(getting traits containing item) looking for '{}'", name);
let mut found_traits = Vec::new();
// Look for the current trait.
if let Some((trait_def_id, _)) = self.current_trait_ref {
if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: None });
}
}
let mut search_module = self.current_module;
loop {
self.get_traits_in_module_containing_item(name, ns, search_module, &mut found_traits);
match search_module.kind {
ModuleKind::Block(..) => search_module = search_module.parent.unwrap(),
_ => break,
}
}
if let Some(prelude) = self.prelude {
if !search_module.no_implicit_prelude {
self.get_traits_in_module_containing_item(name, ns, prelude, &mut found_traits);
}
}
found_traits
}
fn get_traits_in_module_containing_item(&mut self,
name: Name,
ns: Namespace,
module: Module,
found_traits: &mut Vec<TraitCandidate>) {
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 trait_def_id = binding.def().def_id();
if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
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,
};
found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
}
}
}
/// 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_name: Name,
namespace: Namespace,
filter_fn: FilterFn)
-> Vec<ImportSuggestion>
where FilterFn: Fn(Def) -> bool
{
let mut candidates = Vec::new();
let mut worklist = Vec::new();
let mut seen_modules = FxHashSet();
worklist.push((self.graph_root, Vec::new(), false));
while let Some((in_module,
path_segments,
in_module_is_extern)) = worklist.pop() {
self.populate_module_if_necessary(in_module);
in_module.for_each_child(|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_name && ns == namespace {
if filter_fn(name_binding.def()) {
// create the path
let mut segms = path_segments.clone();
segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
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: 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, name_binding.span));
if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
// 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
}
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 {
ast::Visibility::Public => ty::Visibility::Public,
ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
ast::Visibility::Inherited => {
ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
}
ast::Visibility::Restricted { ref path, id } => {
let def = self.smart_resolve_path(id, None, path,
PathSource::Visibility).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 report_errors(&mut self) {
self.report_shadowing_errors();
let mut reported_spans = FxHashSet();
for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
if !reported_spans.insert(span) { continue }
let participle = |binding: &NameBinding| {
if binding.is_import() { "imported" } else { "defined" }
};
let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
format!("consider adding an explicit import of `{}` to disambiguate", name)
} else if let Def::Macro(..) = b1.def() {
format!("macro-expanded {} do not shadow",
if b1.is_import() { "macro imports" } else { "macros" })
} else {
format!("macro-expanded {} do not shadow when used in a macro invocation path",
if b1.is_import() { "imports" } else { "items" })
};
if legacy {
let id = match b2.kind {
NameBindingKind::Import { directive, .. } => directive.id,
_ => unreachable!(),
};
let mut span = MultiSpan::from_span(span);
span.push_span_label(b1.span, msg1);
span.push_span_label(b2.span, msg2);
let msg = format!("`{}` is ambiguous", name);
self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
} else {
let mut err =
self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
err.span_note(b1.span, &msg1);
match b2.def() {
Def::Macro(..) if b2.span == DUMMY_SP =>
err.note(&format!("`{}` is also a builtin macro", name)),
_ => err.span_note(b2.span, &msg2),
};
err.note(&note).emit();
}
}
for &PrivacyError(span, name, binding) in &self.privacy_errors {
if !reported_spans.insert(span) { continue }
if binding.is_extern_crate() {
// Warn when using an inaccessible extern crate.
let node_id = match binding.kind {
NameBindingKind::Import { directive, .. } => directive.id,
_ => unreachable!(),
};
let msg = format!("extern crate `{}` is private", name);
self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg);
} else {
let def = binding.def();
self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name));
}
}
}
fn report_shadowing_errors(&mut self) {
for (name, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
self.resolve_legacy_scope(scope, name, true);
}
let mut reported_errors = FxHashSet();
for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
if self.resolve_legacy_scope(&binding.parent, binding.name, false).is_some() &&
reported_errors.insert((binding.name, binding.span)) {
let msg = format!("`{}` is already in scope", binding.name);
self.session.struct_span_err(binding.span, &msg)
.note("macro-expanded `macro_rules!`s may not shadow \
existing macros (see RFC 1560)")
.emit();
}
}
}
fn report_conflict(&mut self,
parent: Module,
ident: Ident,
ns: Namespace,
binding: &NameBinding,
old_binding: &NameBinding) {
// Error on the second of two conflicting names
if old_binding.span.lo > binding.span.lo {
return self.report_conflict(parent, ident, ns, old_binding, binding);
}
let container = match parent.kind {
ModuleKind::Def(Def::Mod(_), _) => "module",
ModuleKind::Def(Def::Trait(_), _) => "trait",
ModuleKind::Block(..) => "block",
_ => "enum",
};
let (participle, noun) = match old_binding.is_import() {
true => ("imported", "import"),
false => ("defined", "definition"),
};
let (name, span) = (ident.name, binding.span);
if let Some(s) = self.name_already_seen.get(&name) {
if s == &span {
return;
}
}
let msg = {
let kind = match (ns, old_binding.module()) {
(ValueNS, _) => "a value",
(MacroNS, _) => "a macro",
(TypeNS, _) if old_binding.is_extern_crate() => "an extern crate",
(TypeNS, Some(module)) if module.is_normal() => "a module",
(TypeNS, Some(module)) if module.is_trait() => "a trait",
(TypeNS, _) => "a type",
};
format!("{} named `{}` has already been {} in this {}",
kind, name, participle, container)
};
let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
(true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
(true, _) | (_, true) => match 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(), 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.span_label(span, &format!("`{}` already {}", name, participle));
if old_binding.span != syntax_pos::DUMMY_SP {
err.span_label(old_binding.span, &format!("previous {} of `{}` here", noun, name));
}
err.emit();
self.name_already_seen.insert(name, span);
}
fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
let (id, span) = (directive.id, directive.span);
let msg = "`self` no longer imports values".to_string();
self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
}
fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
if self.proc_macro_enabled { return; }
for attr in attrs {
if attr.path.segments.len() > 1 {
continue
}
let ident = attr.path.segments[0].identifier;
let result = self.resolve_lexical_macro_path_segment(ident, MacroNS, None);
if let Ok(binding) = result {
if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
attr::mark_known(attr);
let msg = "attribute procedural macros are experimental";
let feature = "proc_macro";
feature_err(&self.session.parse_sess, feature,
attr.span, GateIssue::Language, msg)
.span_note(binding.span(), "procedural macro imported here")
.emit();
}
}
}
}
}
fn is_struct_like(def: Def) -> bool {
match def {
Def::VariantCtor(_, CtorKind::Fictive) => true,
_ => PathSource::Struct.is_expected(def),
}
}
fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
}
fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
}
fn names_to_string(idents: &[Ident]) -> String {
let mut result = String::new();
for (i, ident) in idents.iter().filter(|i| i.name != keywords::CrateRoot.name()).enumerate() {
if i > 0 {
result.push_str("::");
}
result.push_str(&ident.name.as_str());
}
result
}
fn path_names_to_string(path: &Path) -> String {
names_to_string(&path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>())
}
/// 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(session: &mut DiagnosticBuilder,
candidates: &[ImportSuggestion],
better: bool) {
// don't show more than MAX_CANDIDATES results, so
// we're consistent with the trait suggestions
const MAX_CANDIDATES: usize = 4;
// 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 end = cmp::min(MAX_CANDIDATES, path_strings.len());
session.help(&format!("possible {}candidate{} into scope:{}{}",
better,
msg_diff,
&path_strings[0..end].iter().map(|candidate| {
format!("\n `use {};`", candidate)
}).collect::<String>(),
if path_strings.len() > MAX_CANDIDATES {
format!("\nand {} other candidates",
path_strings.len() - MAX_CANDIDATES)
} else {
"".to_owned()
}
));
}
/// A somewhat inefficient routine to obtain the name of a module.
fn module_to_string(module: Module) -> 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 "???".to_string();
}
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,
}
__build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }