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chromium / external / github.com / rust-lang / rust / e85a0d70b86491752eb501f73b9d2025c5991e8e / . / src / librustc_resolve / lib.rs
blob: b981dfef8908ebf69714096191561a5a1ebae60e [file] [log] [blame]
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![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/")]
#![cfg_attr(not(stage0), deny(warnings))]
#![feature(associated_consts)]
#![feature(borrow_state)]
#![cfg_attr(stage0, feature(dotdot_in_tuple_patterns))]
#![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::ResolveResult::*;
use self::FallbackSuggestion::*;
use self::TypeParameters::*;
use self::RibKind::*;
use self::UseLexicalScopeFlag::*;
use self::ModulePrefixResult::*;
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, DefId};
use rustc::ty;
use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet};
use syntax::ext::hygiene::{Mark, SyntaxContext};
use syntax::ast::{self, FloatTy};
use syntax::ast::{CRATE_NODE_ID, Name, NodeId, Ident, SpannedIdent, IntTy, UintTy};
use syntax::ext::base::SyntaxExtension;
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::{PathSegment, PathParameters, QSelf, TraitItemKind, TraitRef, Ty, TyKind};
use syntax_pos::{Span, DUMMY_SP};
use errors::DiagnosticBuilder;
use std::cell::{Cell, RefCell};
use std::fmt;
use std::mem::replace;
use std::rc::Rc;
use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
use macros::{InvocationData, LegacyBinding, LegacyScope};
// 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;
enum SuggestionType {
Macro(String),
Function(Symbol),
NotFound,
}
/// Candidates for a name resolution failure
struct SuggestedCandidates {
name: String,
candidates: Vec<Path>,
}
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 E0404: is not a trait
IsNotATrait(&'a str, &'a str),
/// error E0405: use of undeclared trait name
UndeclaredTraitName(&'a str, SuggestedCandidates),
/// 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 `{}` from pattern #{} is not bound in pattern #{}
VariableNotBoundInPattern(Name, usize, usize),
/// error E0409: variable is bound with different mode in pattern #{} than in pattern #1
VariableBoundWithDifferentMode(Name, usize, Span),
/// error E0411: use of `Self` outside of an impl or trait
SelfUsedOutsideImplOrTrait,
/// error E0412: use of undeclared
UseOfUndeclared(&'a str, &'a str, SuggestedCandidates),
/// 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 E0423: is a struct variant name, but this expression uses it like a function name
StructVariantUsedAsFunction(&'a str),
/// error E0424: `self` is not available in a static method
SelfNotAvailableInStaticMethod,
/// error E0425: unresolved name
UnresolvedName {
path: &'a str,
message: &'a str,
context: UnresolvedNameContext<'a>,
is_static_method: bool,
is_field: bool,
def: Def,
},
/// 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 E0531: unresolved pattern path kind `name`
PatPathUnresolved(&'a str, &'a Path),
/// error E0532: expected pattern path kind, found another pattern path kind
PatPathUnexpected(&'a str, &'a str, &'a Path),
}
/// Context of where `ResolutionError::UnresolvedName` arose.
#[derive(Clone, PartialEq, Eq, Debug)]
enum UnresolvedNameContext<'a> {
/// `PathIsMod(parent)` indicates that a given path, used in
/// expression context, actually resolved to a module rather than
/// a value. The optional expression attached to the variant is the
/// the parent of the erroneous path expression.
PathIsMod(Option<&'a Expr>),
/// `Other` means we have no extra information about the context
/// of the unresolved name error. (Maybe we could eliminate all
/// such cases; but for now, this is an information-free default.)
Other,
}
fn resolve_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
span: syntax_pos::Span,
resolution_error: ResolutionError<'c>) {
resolve_struct_error(resolver, span, resolution_error).emit();
}
fn resolve_struct_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
span: syntax_pos::Span,
resolution_error: ResolutionError<'c>)
-> DiagnosticBuilder<'a> {
if !resolver.emit_errors {
return resolver.session.diagnostic().struct_dummy();
}
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::IsNotATrait(name, kind_name) => {
let mut err = struct_span_err!(resolver.session,
span,
E0404,
"`{}` is not a trait",
name);
err.span_label(span, &format!("expected trait, found {}", kind_name));
err
}
ResolutionError::UndeclaredTraitName(name, candidates) => {
let mut err = struct_span_err!(resolver.session,
span,
E0405,
"trait `{}` is not in scope",
name);
show_candidates(&mut err, &candidates);
err.span_label(span, &format!("`{}` is not in scope", 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(variable_name, from, to) => {
let mut err = struct_span_err!(resolver.session,
span,
E0408,
"variable `{}` from pattern #{} is not bound in pattern #{}",
variable_name,
from,
to);
err.span_label(span, &format!("pattern doesn't bind `{}`", variable_name));
err
}
ResolutionError::VariableBoundWithDifferentMode(variable_name,
pattern_number,
first_binding_span) => {
let mut err = struct_span_err!(resolver.session,
span,
E0409,
"variable `{}` is bound with different mode in pattern #{} than in \
pattern #1",
variable_name,
pattern_number);
err.span_label(span, &format!("bound in different ways"));
err.span_label(first_binding_span, &format!("first binding"));
err
}
ResolutionError::SelfUsedOutsideImplOrTrait => {
let mut err = struct_span_err!(resolver.session,
span,
E0411,
"use of `Self` outside of an impl or trait");
err.span_label(span, &format!("used outside of impl or trait"));
err
}
ResolutionError::UseOfUndeclared(kind, name, candidates) => {
let mut err = struct_span_err!(resolver.session,
span,
E0412,
"{} `{}` is undefined or not in scope",
kind,
name);
show_candidates(&mut err, &candidates);
err.span_label(span, &format!("undefined or not in scope"));
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::StructVariantUsedAsFunction(path_name) => {
let mut err = struct_span_err!(resolver.session,
span,
E0423,
"`{}` is the name of a struct or struct variant, but this expression \
uses it like a function name",
path_name);
err.span_label(span, &format!("struct called like a function"));
err
}
ResolutionError::SelfNotAvailableInStaticMethod => {
let mut err = struct_span_err!(resolver.session,
span,
E0424,
"`self` is not available in a static method");
err.span_label(span, &format!("not available in static method"));
err.note(&format!("maybe a `self` argument is missing?"));
err
}
ResolutionError::UnresolvedName { path, message: msg, context, is_static_method,
is_field, def } => {
let mut err = struct_span_err!(resolver.session,
span,
E0425,
"unresolved name `{}`",
path);
if msg != "" {
err.span_label(span, &msg);
} else {
err.span_label(span, &format!("unresolved name"));
}
match context {
UnresolvedNameContext::Other => {
if msg.is_empty() && is_static_method && is_field {
err.help("this is an associated function, you don't have access to \
this type's fields or methods");
}
}
UnresolvedNameContext::PathIsMod(parent) => {
err.help(&match parent.map(|parent| &parent.node) {
Some(&ExprKind::Field(_, ident)) => {
format!("to reference an item from the `{module}` module, \
use `{module}::{ident}`",
module = path,
ident = ident.node)
}
Some(&ExprKind::MethodCall(ident, ..)) => {
format!("to call a function from the `{module}` module, \
use `{module}::{ident}(..)`",
module = path,
ident = ident.node)
}
_ => {
format!("{def} `{module}` cannot be used as an expression",
def = def.kind_name(),
module = path)
}
});
}
}
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::PatPathUnresolved(expected_what, path) => {
struct_span_err!(resolver.session,
span,
E0531,
"unresolved {} `{}`",
expected_what,
path)
}
ResolutionError::PatPathUnexpected(expected_what, found_what, path) => {
struct_span_err!(resolver.session,
span,
E0532,
"expected {}, found {} `{}`",
expected_what,
found_what,
path)
}
}
}
#[derive(Copy, Clone)]
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, 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> Visitor for Resolver<'a> {
fn visit_item(&mut self, item: &Item) {
self.resolve_item(item);
}
fn visit_arm(&mut self, arm: &Arm) {
self.resolve_arm(arm);
}
fn visit_block(&mut self, block: &Block) {
self.resolve_block(block);
}
fn visit_expr(&mut self, expr: &Expr) {
self.resolve_expr(expr, None);
}
fn visit_local(&mut self, local: &Local) {
self.resolve_local(local);
}
fn visit_ty(&mut self, ty: &Ty) {
self.resolve_type(ty);
}
fn visit_poly_trait_ref(&mut self, tref: &ast::PolyTraitRef, m: &ast::TraitBoundModifier) {
match self.resolve_trait_reference(tref.trait_ref.ref_id, &tref.trait_ref.path, 0, None) {
Ok(def) => self.record_def(tref.trait_ref.ref_id, def),
Err(_) => {
// error already reported
self.record_def(tref.trait_ref.ref_id, err_path_resolution())
}
}
visit::walk_poly_trait_ref(self, tref, m);
}
fn visit_variant(&mut self,
variant: &ast::Variant,
generics: &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: &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,
declaration: &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();
}
}
pub type ErrorMessage = Option<(Span, String)>;
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum ResolveResult<T> {
Failed(ErrorMessage), // Failed to resolve the name, optional helpful error message.
Indeterminate, // Couldn't determine due to unresolved globs.
Success(T), // Successfully resolved the import.
}
impl<T> ResolveResult<T> {
fn success(self) -> Option<T> {
match self {
Success(t) => Some(t),
_ => None,
}
}
}
enum FallbackSuggestion {
NoSuggestion,
Field,
TraitItem,
TraitMethod(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 with the given expansion
MacroDefinition(Mark),
}
#[derive(Copy, Clone)]
enum UseLexicalScopeFlag {
DontUseLexicalScope,
UseLexicalScope,
}
enum ModulePrefixResult<'a> {
NoPrefixFound,
PrefixFound(Module<'a>, usize),
}
/// 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,
}
}
}
/// A definition along with the index of the rib it was found on
struct LocalDef {
ribs: Option<(Namespace, usize)>,
def: Def,
}
impl LocalDef {
fn from_def(def: Def) -> Self {
LocalDef {
ribs: None,
def: def,
}
}
}
enum LexicalScopeBinding<'a> {
Item(&'a NameBinding<'a>),
LocalDef(LocalDef),
}
impl<'a> LexicalScopeBinding<'a> {
fn local_def(self) -> LocalDef {
match self {
LexicalScopeBinding::LocalDef(local_def) => local_def,
LexicalScopeBinding::Item(binding) => LocalDef::from_def(binding.def()),
}
}
fn item(self) -> Option<&'a NameBinding<'a>> {
match self {
LexicalScopeBinding::Item(binding) => Some(binding),
_ => None,
}
}
}
enum ModuleKind {
Block(NodeId),
Def(Def, Name),
}
/// One node in the tree of modules.
pub struct ModuleS<'a> {
parent: Option<Module<'a>>,
kind: ModuleKind,
// The node id of the closest normal module (`mod`) ancestor (including this module).
normal_ancestor_id: Option<NodeId>,
resolutions: RefCell<FxHashMap<(Name, Namespace), &'a RefCell<NameResolution<'a>>>>,
legacy_macro_resolutions: RefCell<Vec<(Mark, Name, 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<[(Name, &'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 ModuleS<'a>;
impl<'a> ModuleS<'a> {
fn new(parent: Option<Module<'a>>, kind: ModuleKind) -> Self {
ModuleS {
parent: parent,
kind: kind,
normal_ancestor_id: None,
resolutions: RefCell::new(FxHashMap()),
legacy_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(true),
}
}
fn for_each_child<F: FnMut(Name, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
for (&(name, ns), name_resolution) in self.resolutions.borrow().iter() {
name_resolution.borrow().binding.map(|binding| f(name, 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_some()
}
}
impl<'a> fmt::Debug for ModuleS<'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) -> NameBinding<'a>;
}
impl<'a> ToNameBinding<'a> for NameBinding<'a> {
fn to_name_binding(self) -> 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>,
},
Ambiguity {
b1: &'a NameBinding<'a>,
b2: &'a NameBinding<'a>,
}
}
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>,
}
impl<'a> NameBinding<'a> {
fn module(&self) -> Result<Module<'a>, bool /* true if an error has already been reported */> {
match self.kind {
NameBindingKind::Module(module) => Ok(module),
NameBindingKind::Import { binding, .. } => binding.module(),
NameBindingKind::Def(Def::Err) => Err(true),
NameBindingKind::Def(_) => Err(false),
NameBindingKind::Ambiguity { .. } => Err(false),
}
}
fn def(&self) -> Def {
match self.kind {
NameBindingKind::Def(def) => def,
NameBindingKind::Module(module) => module.def().unwrap(),
NameBindingKind::Import { binding, .. } => binding.def(),
NameBindingKind::Ambiguity { .. } => Def::Err,
}
}
// 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("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
}
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,
// Maps the node id of a statement to the expansions of the `macro_rules!`s
// immediately above the statement (if appropriate).
macros_at_scope: FxHashMap<NodeId, Vec<Mark>>,
graph_root: Module<'a>,
prelude: Option<Module<'a>>,
trait_item_map: FxHashMap<(Name, DefId), bool /* is static method? */>,
// 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,
pub def_map: DefMap,
pub freevars: FreevarMap,
freevars_seen: NodeMap<NodeMap<usize>>,
pub export_map: ExportMap,
pub trait_map: TraitMap,
// A map from nodes to modules, both normal (`mod`) modules and 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`.
module_map: NodeMap<Module<'a>>,
extern_crate_roots: FxHashMap<(CrateNum, bool /* MacrosOnly? */), Module<'a>>,
// Whether or not to print error messages. Can be set to true
// when getting additional info for error message suggestions,
// so as to avoid printing duplicate errors
emit_errors: bool,
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)>,
used_crates: FxHashSet<CrateNum>,
pub maybe_unused_trait_imports: NodeSet,
privacy_errors: Vec<PrivacyError<'a>>,
ambiguity_errors: Vec<AmbiguityError<'a>>,
disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
arenas: &'a ResolverArenas<'a>,
dummy_binding: &'a NameBinding<'a>,
new_import_semantics: bool, // true if `#![feature(item_like_imports)]`
use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
pub exported_macros: Vec<ast::MacroDef>,
crate_loader: &'a mut CrateLoader,
macro_names: FxHashSet<Name>,
builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
lexical_macro_resolutions: Vec<(Name, LegacyScope<'a>)>,
macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
macro_exports: Vec<Export>,
// 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>,
}
pub struct ResolverArenas<'a> {
modules: arena::TypedArena<ModuleS<'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: ModuleS<'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> ty::NodeIdTree for Resolver<'a> {
fn is_descendant_of(&self, mut node: NodeId, ancestor: NodeId) -> bool {
while node != ancestor {
node = match self.module_map[&node].parent {
Some(parent) => parent.normal_ancestor_id.unwrap(),
None => return false,
}
}
true
}
}
impl<'a> hir::lowering::Resolver for Resolver<'a> {
fn resolve_generated_global_path(&mut self, path: &hir::Path, is_value: bool) -> Def {
let namespace = if is_value { ValueNS } else { TypeNS };
match self.resolve_crate_relative_path(path.span, &path.segments, namespace) {
Ok(binding) => binding.def(),
Err(true) => Def::Err,
Err(false) => {
let path_name = &format!("{}", path);
let error =
ResolutionError::UnresolvedName {
path: path_name,
message: "",
context: UnresolvedNameContext::Other,
is_static_method: false,
is_field: false,
def: Def::Err,
};
resolve_error(self, path.span, error);
Def::Err
}
}
}
fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
self.def_map.get(&id).cloned()
}
fn record_resolution(&mut self, id: NodeId, def: Def) {
self.def_map.insert(id, PathResolution::new(def));
}
fn definitions(&mut self) -> &mut Definitions {
&mut self.definitions
}
}
trait Named {
fn ident(&self) -> Ident;
}
impl Named for ast::PathSegment {
fn ident(&self) -> Ident {
self.identifier
}
}
impl Named for hir::PathSegment {
fn ident(&self) -> Ident {
Ident::with_empty_ctxt(self.name)
}
}
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 = Def::Mod(DefId::local(CRATE_DEF_INDEX));
let graph_root = arenas.alloc_module(ModuleS {
normal_ancestor_id: Some(CRATE_NODE_ID),
no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
..ModuleS::new(None, ModuleKind::Def(root_def, keywords::Invalid.name()))
});
let mut module_map = NodeMap();
module_map.insert(CRATE_NODE_ID, 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)));
Resolver {
session: session,
definitions: definitions,
macros_at_scope: FxHashMap(),
// 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: None,
},
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,
extern_crate_roots: FxHashMap(),
emit_errors: true,
make_glob_map: make_glob_map == MakeGlobMap::Yes,
glob_map: NodeMap(),
used_imports: FxHashSet(),
used_crates: FxHashSet(),
maybe_unused_trait_imports: NodeSet(),
privacy_errors: Vec::new(),
ambiguity_errors: Vec::new(),
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,
}),
new_import_semantics: session.features.borrow().item_like_imports,
use_extern_macros: session.features.borrow().use_extern_macros,
exported_macros: Vec::new(),
crate_loader: crate_loader,
macro_names: FxHashSet(),
builtin_macros: FxHashMap(),
lexical_macro_resolutions: Vec::new(),
macro_map: FxHashMap(),
macro_exports: Vec::new(),
invocations: invocations,
name_already_seen: FxHashMap(),
}
}
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;
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, local: bool) -> Module<'a> {
self.arenas.alloc_module(ModuleS {
normal_ancestor_id: if local { self.current_module.normal_ancestor_id } else { None },
populated: Cell::new(local),
..ModuleS::new(Some(parent), kind)
})
}
fn record_use(&mut self, name: Name, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
-> bool /* true if an error was reported */ {
// track extern crates for unused_extern_crate lint
if let Some(DefId { krate, .. }) = binding.module().ok().and_then(ModuleS::def_id) {
self.used_crates.insert(krate);
}
match binding.kind {
NameBindingKind::Import { directive, binding, ref used } if !used.get() => {
used.set(true);
self.used_imports.insert((directive.id, ns));
self.add_to_glob_map(directive.id, name);
self.record_use(name, ns, binding, span)
}
NameBindingKind::Import { .. } => false,
NameBindingKind::Ambiguity { b1, b2 } => {
self.ambiguity_errors.push(AmbiguityError {
span: span, name: name, lexical: false, b1: b1, b2: b2,
});
true
}
_ => false
}
}
fn add_to_glob_map(&mut self, id: NodeId, name: Name) {
if self.make_glob_map {
self.glob_map.entry(id).or_insert_with(FxHashSet).insert(name);
}
}
fn expect_module(&mut self, name: Name, binding: &'a NameBinding<'a>, span: Option<Span>)
-> ResolveResult<Module<'a>> {
match binding.module() {
Ok(module) => Success(module),
Err(true) => Failed(None),
Err(false) => {
let msg = format!("Not a module `{}`", name);
Failed(span.map(|span| (span, msg)))
}
}
}
/// Resolves the given module path from the given root `search_module`.
fn resolve_module_path_from_root(&mut self,
mut search_module: Module<'a>,
module_path: &[Ident],
index: usize,
span: Option<Span>)
-> ResolveResult<Module<'a>> {
fn search_parent_externals<'a>(this: &mut Resolver<'a>, needle: Name, module: Module<'a>)
-> Option<Module<'a>> {
match this.resolve_name_in_module(module, needle, TypeNS, false, false, None) {
Success(binding) if binding.is_extern_crate() => Some(module),
_ => if let (&ModuleKind::Def(..), Some(parent)) = (&module.kind, module.parent) {
search_parent_externals(this, needle, parent)
} else {
None
},
}
}
let mut index = index;
let module_path_len = module_path.len();
// Resolve the module part of the path. This does not involve looking
// upward though scope chains; we simply resolve names directly in
// modules as we go.
while index < module_path_len {
let name = module_path[index].name;
match self.resolve_name_in_module(search_module, name, TypeNS, false, false, span) {
Failed(_) => {
let segment_name = name.as_str();
let module_name = module_to_string(search_module);
let msg = if "???" == &module_name {
let current_module = self.current_module;
match search_parent_externals(self, name, current_module) {
Some(module) => {
let path_str = names_to_string(module_path);
let target_mod_str = module_to_string(&module);
let current_mod_str = module_to_string(current_module);
let prefix = if target_mod_str == current_mod_str {
"self::".to_string()
} else {
format!("{}::", target_mod_str)
};
format!("Did you mean `{}{}`?", prefix, path_str)
}
None => format!("Maybe a missing `extern crate {};`?", segment_name),
}
} else {
format!("Could not find `{}` in `{}`", segment_name, module_name)
};
return Failed(span.map(|span| (span, msg)));
}
Indeterminate => {
debug!("(resolving module path for import) module resolution is \
indeterminate: {}",
name);
return Indeterminate;
}
Success(binding) => {
// Check to see whether there are type bindings, and, if
// so, whether there is a module within.
match self.expect_module(name, binding, span) {
Success(module) => search_module = module,
result @ _ => return result,
}
}
}
index += 1;
}
return Success(search_module);
}
/// Attempts to resolve the module part of an import directive or path
/// rooted at the given module.
fn resolve_module_path(&mut self,
module_path: &[Ident],
use_lexical_scope: UseLexicalScopeFlag,
span: Option<Span>)
-> ResolveResult<Module<'a>> {
if module_path.len() == 0 {
return Success(self.graph_root) // Use the crate root
}
debug!("(resolving module path for import) processing `{}` rooted at `{}`",
names_to_string(module_path),
module_to_string(self.current_module));
// Resolve the module prefix, if any.
let module_prefix_result = self.resolve_module_prefix(module_path, span);
let search_module;
let start_index;
match module_prefix_result {
Failed(err) => return Failed(err),
Indeterminate => {
debug!("(resolving module path for import) indeterminate; bailing");
return Indeterminate;
}
Success(NoPrefixFound) => {
// There was no prefix, so we're considering the first element
// of the path. How we handle this depends on whether we were
// instructed to use lexical scope or not.
match use_lexical_scope {
DontUseLexicalScope => {
// This is a crate-relative path. We will start the
// resolution process at index zero.
search_module = self.graph_root;
start_index = 0;
}
UseLexicalScope => {
// This is not a crate-relative path. We resolve the
// first component of the path in the current lexical
// scope and then proceed to resolve below that.
let ident = module_path[0];
let lexical_binding =
self.resolve_ident_in_lexical_scope(ident, TypeNS, span);
if let Some(binding) = lexical_binding.and_then(LexicalScopeBinding::item) {
match self.expect_module(ident.name, binding, span) {
Success(containing_module) => {
search_module = containing_module;
start_index = 1;
}
result @ _ => return result,
}
} else {
let msg =
format!("Use of undeclared type or module `{}`", ident.name);
return Failed(span.map(|span| (span, msg)));
}
}
}
}
Success(PrefixFound(ref containing_module, index)) => {
search_module = containing_module;
start_index = index;
}
}
self.resolve_module_path_from_root(search_module, module_path, start_index, span)
}
/// 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::with_empty_ctxt(ident.name);
}
// 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::LocalDef(LocalDef {
ribs: Some((ns, i)),
def: def,
}));
}
if let ModuleRibKind(module) = self.ribs[ns][i].kind {
let name = ident.name;
let item = self.resolve_name_in_module(module, name, ns, true, false, record_used);
if let Success(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_name_in_module(prelude, name, ns, false, false, None).success()
}).map(LexicalScopeBinding::Item)
} else {
return None;
}
}
if let MacroDefinition(mac) = 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 (source_ctxt, source_macro) = ident.ctxt.source();
if source_macro == mac {
ident.ctxt = source_ctxt;
}
}
}
None
}
/// Resolves a "module prefix". A module prefix is one or both of (a) `self::`;
/// (b) some chain of `super::`.
/// grammar: (SELF MOD_SEP ) ? (SUPER MOD_SEP) *
fn resolve_module_prefix(&mut self, module_path: &[Ident], span: Option<Span>)
-> ResolveResult<ModulePrefixResult<'a>> {
if &*module_path[0].name.as_str() == "$crate" {
return Success(PrefixFound(self.resolve_crate_var(module_path[0].ctxt), 1));
}
// Start at the current module if we see `self` or `super`, or at the
// top of the crate otherwise.
let mut i = match &*module_path[0].name.as_str() {
"self" => 1,
"super" => 0,
_ => return Success(NoPrefixFound),
};
let mut containing_module =
self.module_map[&self.current_module.normal_ancestor_id.unwrap()];
// Now loop through all the `super`s we find.
while i < module_path.len() && "super" == module_path[i].name.as_str() {
debug!("(resolving module prefix) resolving `super` at {}",
module_to_string(&containing_module));
if let Some(parent) = containing_module.parent {
containing_module = self.module_map[&parent.normal_ancestor_id.unwrap()];
i += 1;
} else {
let msg = "There are too many initial `super`s.".into();
return Failed(span.map(|span| (span, msg)));
}
}
debug!("(resolving module prefix) finished resolving prefix at {}",
module_to_string(&containing_module));
return Success(PrefixFound(containing_module, i));
}
fn resolve_crate_var(&mut self, mut crate_var_ctxt: SyntaxContext) -> Module<'a> {
while crate_var_ctxt.source().0 != SyntaxContext::empty() {
crate_var_ctxt = crate_var_ctxt.source().0;
}
let module = self.invocations[&crate_var_ctxt.source().1].module.get();
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 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(mac) => {
// If an invocation of this macro created `ident`, give up on `ident`
// and switch to `ident`'s source from the macro definition.
let (source_ctxt, source_macro) = ident.ctxt.source();
if source_macro == mac {
ident.ctxt = source_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);
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), |_, _| {}, None);
}
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 {
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) => {
// Resolve prefix of an import with empty braces (issue #28388)
if items.is_empty() && !prefix.segments.is_empty() {
match self.resolve_crate_relative_path(prefix.span,
&prefix.segments,
TypeNS) {
Ok(binding) => {
let def = binding.def();
self.record_def(item.id, PathResolution::new(def));
}
Err(true) => self.record_def(item.id, err_path_resolution()),
Err(false) => {
resolve_error(self,
prefix.span,
ResolutionError::FailedToResolve(
&path_names_to_string(prefix, 0)));
self.record_def(item.id, err_path_resolution());
}
}
}
}
_ => {}
}
}
ItemKind::ExternCrate(_) => {
// 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 resolve_trait_reference(&mut self,
id: NodeId,
trait_path: &Path,
path_depth: usize,
generics: Option<&Generics>)
-> Result<PathResolution, ()> {
self.resolve_path(id, trait_path, path_depth, TypeNS).and_then(|path_res| {
match path_res.base_def {
Def::Trait(_) => {
debug!("(resolving trait) found trait def: {:?}", path_res);
return Ok(path_res);
}
Def::Err => return Err(true),
_ => {}
}
let mut err = resolve_struct_error(self, trait_path.span, {
ResolutionError::IsNotATrait(&path_names_to_string(trait_path, path_depth),
path_res.base_def.kind_name())
});
if let Some(generics) = generics {
if let Some(span) = generics.span_for_name(
&path_names_to_string(trait_path, path_depth)) {
err.span_label(span, &"type parameter defined here");
}
}
// If it's a typedef, give a note
if let Def::TyAlias(..) = path_res.base_def {
err.note(&format!("type aliases cannot be used for traits"));
}
err.emit();
Err(true)
}).map_err(|error_reported| {
if error_reported { return }
// find possible candidates
let trait_name = trait_path.segments.last().unwrap().identifier.name;
let candidates =
self.lookup_candidates(
trait_name,
TypeNS,
|def| match def {
Def::Trait(_) => true,
_ => false,
},
);
// create error object
let name = &path_names_to_string(trait_path, path_depth);
let error =
ResolutionError::UndeclaredTraitName(
name,
candidates,
);
resolve_error(self, trait_path.span, error);
})
}
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,
generics: Option<&Generics>)
-> 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 {
if let Ok(path_res) = self.resolve_trait_reference(trait_ref.ref_id,
&trait_ref.path,
0,
generics) {
assert!(path_res.depth == 0);
self.record_def(trait_ref.ref_id, path_res);
new_val = Some((path_res.base_def.def_id(), trait_ref.clone()));
new_id = Some(path_res.base_def.def_id());
} else {
self.record_def(trait_ref.ref_id, err_path_resolution());
}
visit::walk_trait_ref(self, trait_ref);
}
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| {
// Resolve the type parameters.
this.visit_generics(generics);
// Resolve the trait reference, if necessary.
this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
// Resolve the self type.
this.visit_ty(self_type);
let item_def_id = this.definitions.local_def_id(item_id);
this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
this.with_current_self_type(self_type, |this| {
for impl_item in impl_items {
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,
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,
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,
impl_item.span,
|n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
this.visit_ty(ty);
}
ImplItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
}
}
});
});
}, Some(&generics));
});
}
fn check_trait_item<F>(&self, name: Name, 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(&(name, did)) {
let path_str = path_names_to_string(&trait_ref.path, 0);
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) {
Some(&PathResolution { base_def: 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 map_0 = self.binding_mode_map(&arm.pats[0]);
for (i, p) in arm.pats.iter().enumerate() {
let map_i = self.binding_mode_map(&p);
for (&key, &binding_0) in &map_0 {
match map_i.get(&key) {
None => {
let error = ResolutionError::VariableNotBoundInPattern(key.name, 1, i + 1);
resolve_error(self, p.span, error);
}
Some(binding_i) => {
if binding_0.binding_mode != binding_i.binding_mode {
resolve_error(self,
binding_i.span,
ResolutionError::VariableBoundWithDifferentMode(
key.name,
i + 1,
binding_0.span));
}
}
}
}
for (&key, &binding) in &map_i {
if !map_0.contains_key(&key) {
resolve_error(self,
binding.span,
ResolutionError::VariableNotBoundInPattern(key.name, i + 1, 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.module_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 Some(marks) = self.macros_at_scope.remove(&stmt.id) {
num_macro_definition_ribs += marks.len() as u32;
for mark in marks {
self.ribs[ValueNS].push(Rib::new(MacroDefinition(mark)));
self.label_ribs.push(Rib::new(MacroDefinition(mark)));
}
}
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 resolve_type(&mut self, ty: &Ty) {
match ty.node {
TyKind::Path(ref maybe_qself, ref path) => {
// This is a path in the type namespace. Walk through scopes
// looking for it.
if let Some(def) = self.resolve_possibly_assoc_item(ty.id, maybe_qself.as_ref(),
path, TypeNS) {
match def.base_def {
Def::Mod(..) if def.depth == 0 => {
self.session.span_err(path.span, "expected type, found module");
self.record_def(ty.id, err_path_resolution());
}
_ => {
// Write the result into the def map.
debug!("(resolving type) writing resolution for `{}` (id {}) = {:?}",
path_names_to_string(path, 0), ty.id, def);
self.record_def(ty.id, def);
}
}
} else {
self.record_def(ty.id, err_path_resolution());
// Keep reporting some errors even if they're ignored above.
if let Err(true) = self.resolve_path(ty.id, path, 0, TypeNS) {
// `resolve_path` already reported the error
} else {
let kind = if maybe_qself.is_some() {
"associated type"
} else {
"type name"
};
let is_invalid_self_type_name = path.segments.len() > 0 &&
maybe_qself.is_none() &&
path.segments[0].identifier.name ==
keywords::SelfType.name();
if is_invalid_self_type_name {
resolve_error(self,
ty.span,
ResolutionError::SelfUsedOutsideImplOrTrait);
} else {
let segment = path.segments.last();
let segment = segment.expect("missing name in path");
let type_name = segment.identifier.name;
let candidates =
self.lookup_candidates(
type_name,
TypeNS,
|def| match def {
Def::Trait(_) |
Def::Enum(_) |
Def::Struct(_) |
Def::Union(_) |
Def::TyAlias(_) => true,
_ => false,
},
);
// create error object
let name = &path_names_to_string(path, 0);
let error =
ResolutionError::UseOfUndeclared(
kind,
name,
candidates,
);
resolve_error(self, ty.span, error);
}
}
}
}
_ => {}
}
// Resolve embedded types.
visit::walk_ty(self, ty);
}
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_path<ExpectedFn>(&mut self,
pat_id: NodeId,
qself: Option<&QSelf>,
path: &Path,
namespace: Namespace,
expected_fn: ExpectedFn,
expected_what: &str)
where ExpectedFn: FnOnce(Def) -> bool
{
let resolution = if let Some(resolution) = self.resolve_possibly_assoc_item(pat_id,
qself, path, namespace) {
if resolution.depth == 0 {
if expected_fn(resolution.base_def) || resolution.base_def == Def::Err {
resolution
} else {
resolve_error(
self,
path.span,
ResolutionError::PatPathUnexpected(expected_what,
resolution.kind_name(), path)
);
err_path_resolution()
}
} else {
// 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 namespace == ValueNS {
let item_name = path.segments.last().unwrap().identifier.name;
let traits = self.get_traits_containing_item(item_name);
self.trait_map.insert(pat_id, traits);
}
resolution
}
} else {
if let Err(false) = self.resolve_path(pat_id, path, 0, namespace) {
resolve_error(
self,
path.span,
ResolutionError::PatPathUnresolved(expected_what, path)
);
}
err_path_resolution()
};
self.record_def(pat_id, resolution);
}
fn resolve_struct_path(&mut self, node_id: NodeId, path: &Path) {
// Resolution logic is equivalent for expressions and patterns,
// reuse `resolve_pattern_path` for both.
self.resolve_pattern_path(node_id, None, path, TypeNS, |def| {
match def {
Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
_ => false,
}
}, "struct, variant or union type");
}
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.
let name = ident.node.name;
self.record_use(name, 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.resolve_pattern_path(pat.id, None, path, ValueNS, |def| {
match def {
Def::StructCtor(_, CtorKind::Fn) |
Def::VariantCtor(_, CtorKind::Fn) => true,
_ => false,
}
}, "tuple struct/variant");
}
PatKind::Path(ref qself, ref path) => {
self.resolve_pattern_path(pat.id, qself.as_ref(), path, ValueNS, |def| {
match def {
Def::StructCtor(_, CtorKind::Const) |
Def::VariantCtor(_, CtorKind::Const) |
Def::Const(..) | Def::AssociatedConst(..) => true,
_ => false,
}
}, "unit struct/variant or constant");
}
PatKind::Struct(ref path, ..) => {
self.resolve_struct_path(pat.id, path);
}
_ => {}
}
true
});
visit::walk_pat(self, pat);
}
/// Handles paths that may refer to associated items
fn resolve_possibly_assoc_item(&mut self,
id: NodeId,
maybe_qself: Option<&QSelf>,
path: &Path,
namespace: Namespace)
-> Option<PathResolution> {
let max_assoc_types;
match maybe_qself {
Some(qself) => {
if qself.position == 0 {
// FIXME: Create some fake resolution that can't possibly be a type.
return Some(PathResolution {
base_def: Def::Mod(self.definitions.local_def_id(ast::CRATE_NODE_ID)),
depth: path.segments.len(),
});
}
max_assoc_types = path.segments.len() - qself.position;
// Make sure the trait is valid.
let _ = self.resolve_trait_reference(id, path, max_assoc_types, None);
}
None => {
max_assoc_types = path.segments.len();
}
}
let mut resolution = self.with_no_errors(|this| {
this.resolve_path(id, path, 0, namespace).ok()
});
for depth in 1..max_assoc_types {
if resolution.is_some() {
break;
}
self.with_no_errors(|this| {
let partial_resolution = this.resolve_path(id, path, depth, TypeNS).ok();
if let Some(Def::Mod(..)) = partial_resolution.map(|r| r.base_def) {
// Modules cannot have associated items
} else {
resolution = partial_resolution;
}
});
}
resolution
}
/// Skips `path_depth` trailing segments, which is also reflected in the
/// returned value. See `hir::def::PathResolution` for more info.
fn resolve_path(&mut self, id: NodeId, path: &Path, path_depth: usize, namespace: Namespace)
-> Result<PathResolution, bool /* true if an error was reported */ > {
debug!("resolve_path(id={:?} path={:?}, path_depth={:?})", id, path, path_depth);
let span = path.span;
let segments = &path.segments[..path.segments.len() - path_depth];
let mk_res = |def| PathResolution { base_def: def, depth: path_depth };
if path.global {
let binding = self.resolve_crate_relative_path(span, segments, namespace);
return binding.map(|binding| mk_res(binding.def()));
}
// Try to find a path to an item in a module.
let last_ident = segments.last().unwrap().identifier;
// Resolve a single identifier with fallback to primitive types
let resolve_identifier_with_fallback = |this: &mut Self, record_used| {
let def = this.resolve_identifier(last_ident, namespace, record_used);
match def {
None | Some(LocalDef{def: Def::Mod(..), ..}) if namespace == TypeNS =>
this.primitive_type_table
.primitive_types
.get(&last_ident.name)
.map_or(def, |prim_ty| Some(LocalDef::from_def(Def::PrimTy(*prim_ty)))),
_ => def
}
};
if segments.len() == 1 {
// 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.
let def = resolve_identifier_with_fallback(self, Some(span)).ok_or(false);
return def.and_then(|def| self.adjust_local_def(def, span).ok_or(true)).map(mk_res);
}
let unqualified_def = resolve_identifier_with_fallback(self, None);
let qualified_binding = self.resolve_module_relative_path(span, segments, namespace);
match (qualified_binding, unqualified_def) {
(Ok(binding), Some(ref ud)) if binding.def() == ud.def &&
segments[0].identifier.name.as_str() != "$crate" => {
self.session
.add_lint(lint::builtin::UNUSED_QUALIFICATIONS,
id,
span,
"unnecessary qualification".to_string());
}
_ => {}
}
qualified_binding.map(|binding| mk_res(binding.def()))
}
// Resolve a single identifier
fn resolve_identifier(&mut self,
identifier: Ident,
namespace: Namespace,
record_used: Option<Span>)
-> Option<LocalDef> {
if identifier.name == keywords::Invalid.name() {
return None;
}
self.resolve_ident_in_lexical_scope(identifier, namespace, record_used)
.map(LexicalScopeBinding::local_def)
}
// Resolve a local definition, potentially adjusting for closures.
fn adjust_local_def(&mut self, local_def: LocalDef, span: Span) -> Option<Def> {
let ribs = match local_def.ribs {
Some((ns, i)) => &self.ribs[ns][i + 1..],
None => &[] as &[_],
};
let mut def = local_def.def;
match def {
Def::Upvar(..) => {
span_bug!(span, "unexpected {:?} in bindings", def)
}
Def::Local(def_id) => {
for rib in ribs {
match rib.kind {
NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) => {
// 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();
vec.push(Freevar {
def: prev_def,
span: span,
});
def = Def::Upvar(def_id, depth, function_id);
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.
resolve_error(self,
span,
ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
return None;
}
ConstantItemRibKind => {
// Still doesn't deal with upvars
resolve_error(self,
span,
ResolutionError::AttemptToUseNonConstantValueInConstant);
return None;
}
}
}
}
Def::TyParam(..) | Def::SelfTy(..) => {
for rib in ribs {
match rib.kind {
NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
ModuleRibKind(..) | MacroDefinition(..) => {
// Nothing to do. Continue.
}
ItemRibKind => {
// This was an attempt to use a type parameter outside
// its scope.
resolve_error(self,
span,
ResolutionError::TypeParametersFromOuterFunction);
return None;
}
ConstantItemRibKind => {
// see #9186
resolve_error(self, span, ResolutionError::OuterTypeParameterContext);
return None;
}
}
}
}
_ => {}
}
return Some(def);
}
// resolve a "module-relative" path, e.g. a::b::c
fn resolve_module_relative_path(&mut self,
span: Span,
segments: &[ast::PathSegment],
namespace: Namespace)
-> Result<&'a NameBinding<'a>,
bool /* true if an error was reported */> {
let module_path =
segments.split_last().unwrap().1.iter().map(|ps| ps.identifier).collect::<Vec<_>>();
let module = match self.resolve_module_path(&module_path, UseLexicalScope, Some(span)) {
Failed(err) => {
if let Some((span, msg)) = err {
resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
}
return Err(true);
}
Indeterminate => return Err(false),
Success(module) => module,
};
let name = segments.last().unwrap().identifier.name;
let result = self.resolve_name_in_module(module, name, namespace, false, false, Some(span));
result.success().ok_or(false)
}
/// Invariant: This must be called only during main resolution, not during
/// import resolution.
fn resolve_crate_relative_path<T>(&mut self, span: Span, segments: &[T], namespace: Namespace)
-> Result<&'a NameBinding<'a>,
bool /* true if an error was reported */>
where T: Named,
{
let module_path = segments.split_last().unwrap().1.iter().map(T::ident).collect::<Vec<_>>();
let root = self.graph_root;
let module = match self.resolve_module_path_from_root(root, &module_path, 0, Some(span)) {
Failed(err) => {
if let Some((span, msg)) = err {
resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
}
return Err(true);
}
Indeterminate => return Err(false),
Success(module) => module,
};
let name = segments.last().unwrap().ident().name;
let result = self.resolve_name_in_module(module, name, namespace, false, false, Some(span));
result.success().ok_or(false)
}
fn with_no_errors<T, F>(&mut self, f: F) -> T
where F: FnOnce(&mut Resolver) -> T
{
self.emit_errors = false;
let rs = f(self);
self.emit_errors = true;
rs
}
// 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 find_fallback_in_self_type(&mut self, name: Name) -> FallbackSuggestion {
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,
}
}
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.depth == 0 => {
if let Some(field_names) = self.field_names.get(&did) {
if field_names.iter().any(|&field_name| name == field_name) {
return Field;
}
}
}
_ => {}
}
}
}
// Look for a method in the current trait.
if let Some((trait_did, ref trait_ref)) = self.current_trait_ref {
if let Some(&is_static_method) = self.trait_item_map.get(&(name, trait_did)) {
if is_static_method {
return TraitMethod(path_names_to_string(&trait_ref.path, 0));
} else {
return TraitItem;
}
}
}
NoSuggestion
}
fn find_best_match(&mut self, name: &str) -> SuggestionType {
if let Some(macro_name) = self.macro_names.iter().find(|n| n.as_str() == name) {
return SuggestionType::Macro(format!("{}!", macro_name));
}
let names = self.ribs[ValueNS]
.iter()
.rev()
.flat_map(|rib| rib.bindings.keys().map(|ident| &ident.name));
if let Some(found) = find_best_match_for_name(names, name, None) {
if found != name {
return SuggestionType::Function(found);
}
} SuggestionType::NotFound
}
fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
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);
this.visit_block(block);
});
} else {
self.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 maybe_qself, ref path) => {
// This is a local path in the value namespace. Walk through
// scopes looking for it.
if let Some(path_res) = self.resolve_possibly_assoc_item(expr.id,
maybe_qself.as_ref(), path, ValueNS) {
// Check if struct variant
let is_struct_variant = match path_res.base_def {
Def::VariantCtor(_, CtorKind::Fictive) => true,
_ => false,
};
if is_struct_variant {
let path_name = path_names_to_string(path, 0);
let mut err = resolve_struct_error(self,
expr.span,
ResolutionError::StructVariantUsedAsFunction(&path_name));
let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
path_name);
if self.emit_errors {
err.help(&msg);
} else {
err.span_help(expr.span, &msg);
}
err.emit();
self.record_def(expr.id, err_path_resolution());
} else {
// Write the result into the def map.
debug!("(resolving expr) resolved `{}`",
path_names_to_string(path, 0));
// Partial resolutions will need the set of traits in scope,
// so they can be completed during typeck.
if path_res.depth != 0 {
let method_name = path.segments.last().unwrap().identifier.name;
let traits = self.get_traits_containing_item(method_name);
self.trait_map.insert(expr.id, traits);
}
self.record_def(expr.id, path_res);
}
} else {
// Be helpful if the name refers to a struct
let path_name = path_names_to_string(path, 0);
let type_res = self.with_no_errors(|this| {
this.resolve_path(expr.id, path, 0, TypeNS)
});
self.record_def(expr.id, err_path_resolution());
if let Ok(Def::Struct(..)) = type_res.map(|r| r.base_def) {
let error_variant =
ResolutionError::StructVariantUsedAsFunction(&path_name);
let mut err = resolve_struct_error(self, expr.span, error_variant);
let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
path_name);
if self.emit_errors {
err.help(&msg);
} else {
err.span_help(expr.span, &msg);
}
err.emit();
} else {
// Keep reporting some errors even if they're ignored above.
if let Err(true) = self.resolve_path(expr.id, path, 0, ValueNS) {
// `resolve_path` already reported the error
} else {
let mut method_scope = false;
let mut is_static = false;
self.ribs[ValueNS].iter().rev().all(|rib| {
method_scope = match rib.kind {
MethodRibKind(is_static_) => {
is_static = is_static_;
true
}
ItemRibKind | ConstantItemRibKind => false,
_ => return true, // Keep advancing
};
false // Stop advancing
});
if method_scope &&
&path_name[..] == keywords::SelfValue.name().as_str() {
resolve_error(self,
expr.span,
ResolutionError::SelfNotAvailableInStaticMethod);
} else {
let last_name = path.segments.last().unwrap().identifier.name;
let (mut msg, is_field) =
match self.find_fallback_in_self_type(last_name) {
NoSuggestion => {
// limit search to 5 to reduce the number
// of stupid suggestions
(match self.find_best_match(&path_name) {
SuggestionType::Macro(s) => {
format!("the macro `{}`", s)
}
SuggestionType::Function(s) => format!("`{}`", s),
SuggestionType::NotFound => "".to_string(),
}, false)
}
Field => {
(if is_static && method_scope {
"".to_string()
} else {
format!("`self.{}`", path_name)
}, true)
}
TraitItem => (format!("to call `self.{}`", path_name), false),
TraitMethod(path_str) =>
(format!("to call `{}::{}`", path_str, path_name), false),
};
let mut context = UnresolvedNameContext::Other;
let mut def = Def::Err;
if !msg.is_empty() {
msg = format!("did you mean {}?", msg);
} else {
// we display a help message if this is a module
let name_path: Vec<_> =
path.segments.iter().map(|seg| seg.identifier).collect();
match self.resolve_module_path(&name_path[..],
UseLexicalScope,
Some(expr.span)) {
Success(e) => {
if let Some(def_type) = e.def() {
def = def_type;
}
context = UnresolvedNameContext::PathIsMod(parent);
},
_ => {},
};
}
resolve_error(self,
expr.span,
ResolutionError::UnresolvedName {
path: &path_name,
message: &msg,
context: context,
is_static_method: method_scope && is_static,
is_field: is_field,
def: def,
});
}
}
}
}
visit::walk_expr(self, expr);
}
ExprKind::Struct(ref path, ..) => {
self.resolve_struct_path(expr.id, path);
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!")
}
}
}
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.visit_expr(subexpression);
self.resolve_labeled_block(label, expr.id, &block);
}
ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
self.visit_expr(subexpression);
self.ribs[ValueNS].push(Rib::new(NormalRibKind));
self.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
self.resolve_labeled_block(label, expr.id, block);
self.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();
}
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);
}
}
_ => {
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);
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);
self.trait_map.insert(expr.id, traits);
}
_ => {
// Nothing to do.
}
}
}
fn get_traits_containing_item(&mut self, name: Name) -> Vec<TraitCandidate> {
debug!("(getting traits containing item) looking for '{}'", name);
fn add_trait_info(found_traits: &mut Vec<TraitCandidate>,
trait_def_id: DefId,
import_id: Option<NodeId>,
name: Name) {
debug!("(adding trait info) found trait {:?} for method '{}'",
trait_def_id,
name);
found_traits.push(TraitCandidate {
def_id: trait_def_id,
import_id: import_id,
});
}
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(&(name, trait_def_id)) {
add_trait_info(&mut found_traits, trait_def_id, None, name);
}
}
let mut search_module = self.current_module;
loop {
// Look for trait children.
let mut search_in_module = |this: &mut Self, module: Module<'a>| {
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 this.trait_item_map.contains_key(&(name, trait_def_id)) {
let mut import_id = None;
if let NameBindingKind::Import { directive, .. } = binding.kind {
let id = directive.id;
this.maybe_unused_trait_imports.insert(id);
this.add_to_glob_map(id, trait_name);
import_id = Some(id);
}
add_trait_info(&mut found_traits, trait_def_id, import_id, name);
}
}
};
search_in_module(self, search_module);
if let ModuleKind::Block(..) = search_module.kind {
search_module = search_module.parent.unwrap();
} else {
if !search_module.no_implicit_prelude {
self.prelude.map(|prelude| search_in_module(self, prelude));
}
break;
}
}
found_traits
}
/// 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_candidates<FilterFn>(&mut self,
lookup_name: Name,
namespace: Namespace,
filter_fn: FilterFn) -> SuggestedCandidates
where FilterFn: Fn(Def) -> bool {
let mut lookup_results = Vec::new();
let mut worklist = Vec::new();
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(|name, ns, name_binding| {
// avoid imports entirely
if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
// collect results based on the filter function
if name == lookup_name && ns == namespace {
if filter_fn(name_binding.def()) {
// create the path
let ident = Ident::with_empty_ctxt(name);
let params = PathParameters::none();
let segment = PathSegment {
identifier: ident,
parameters: params,
};
let span = name_binding.span;
let mut segms = path_segments.clone();
segms.push(segment);
let path = Path {
span: span,
global: true,
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 {
lookup_results.push(path);
}
}
}
// collect submodules to explore
if let Ok(module) = name_binding.module() {
// form the path
let mut path_segments = path_segments.clone();
path_segments.push(PathSegment {
identifier: Ident::with_empty_ctxt(name),
parameters: PathParameters::none(),
});
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 !worklist.iter().any(|&(m, ..)| m.def() == module.def()) {
worklist.push((module, path_segments, is_extern));
}
}
}
})
}
SuggestedCandidates {
name: lookup_name.as_str().to_string(),
candidates: lookup_results,
}
}
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 {
let (path, id) = match *vis {
ast::Visibility::Public => return ty::Visibility::Public,
ast::Visibility::Crate(_) => return ty::Visibility::Restricted(ast::CRATE_NODE_ID),
ast::Visibility::Restricted { ref path, id } => (path, id),
ast::Visibility::Inherited => {
return ty::Visibility::Restricted(self.current_module.normal_ancestor_id.unwrap());
}
};
let segments: Vec<_> = path.segments.iter().map(|seg| seg.identifier).collect();
let mut path_resolution = err_path_resolution();
let vis = match self.resolve_module_path(&segments, DontUseLexicalScope, Some(path.span)) {
Success(module) => {
path_resolution = PathResolution::new(module.def().unwrap());
ty::Visibility::Restricted(module.normal_ancestor_id.unwrap())
}
Indeterminate => unreachable!(),
Failed(err) => {
if let Some((span, msg)) = err {
self.session.span_err(span, &format!("failed to resolve module path. {}", msg));
}
ty::Visibility::Public
}
};
self.def_map.insert(id, path_resolution);
if !self.is_accessible(vis) {
let msg = format!("visibilities can only be restricted to ancestor modules");
self.session.span_err(path.span, &msg);
}
vis
}
fn is_accessible(&self, vis: ty::Visibility) -> bool {
vis.is_accessible_from(self.current_module.normal_ancestor_id.unwrap(), self)
}
fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
vis.is_accessible_from(module.normal_ancestor_id.unwrap(), self)
}
fn report_errors(&mut self) {
self.report_shadowing_errors();
let mut reported_spans = FxHashSet();
for &AmbiguityError { span, name, b1, b2, lexical } in &self.ambiguity_errors {
if !reported_spans.insert(span) { continue }
let msg1 = format!("`{}` could resolve to the name imported here", name);
let msg2 = format!("`{}` could also resolve to the name imported here", name);
self.session.struct_span_err(span, &format!("`{}` is ambiguous", name))
.span_note(b1.span, &msg1)
.span_note(b2.span, &msg2)
.note(&if lexical || !b1.is_glob_import() {
"macro-expanded macro imports do not shadow".to_owned()
} else {
format!("consider adding an explicit import of `{}` to disambiguate", name)
})
.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,
name: Name,
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, name, 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 span = 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, Ok(module)) if module.is_normal() => "a module",
(TypeNS, Ok(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) => {
let mut e = struct_span_err!(self.session, span, E0259, "{}", msg);
e.span_label(span, &format!("`{}` was already imported", name));
e
},
(true, _) | (_, true) if binding.is_import() && old_binding.is_import() => {
let mut e = struct_span_err!(self.session, span, E0254, "{}", msg);
e.span_label(span, &"already imported");
e
},
(true, _) | (_, true) => {
let mut e = struct_span_err!(self.session, span, E0260, "{}", msg);
e.span_label(span, &format!("`{}` already imported", name));
e
},
_ => match (old_binding.is_import(), binding.is_import()) {
(false, false) => {
let mut e = struct_span_err!(self.session, span, E0428, "{}", msg);
e.span_label(span, &format!("already defined"));
e
},
(true, true) => {
let mut e = struct_span_err!(self.session, span, E0252, "{}", msg);
e.span_label(span, &format!("already imported"));
e
},
_ => {
let mut e = struct_span_err!(self.session, span, E0255, "{}", msg);
e.span_label(span, &format!("`{}` was already imported", name));
e
}
},
};
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 names_to_string(names: &[Ident]) -> String {
let mut first = true;
let mut result = String::new();
for ident in names {
if first {
first = false
} else {
result.push_str("::")
}
result.push_str(&ident.name.as_str());
}
result
}
fn path_names_to_string(path: &Path, depth: usize) -> String {
let names: Vec<_> =
path.segments[..path.segments.len() - depth].iter().map(|seg| seg.identifier).collect();
names_to_string(&names)
}
/// 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: &SuggestedCandidates) {
let paths = &candidates.candidates;
if paths.len() > 0 {
// don't show more than MAX_CANDIDATES results, so
// we're consistent with the trait suggestions
const MAX_CANDIDATES: usize = 5;
// 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<_> = paths.into_iter()
.map(|p| path_names_to_string(&p, 0))
.collect();
path_strings.sort();
// behave differently based on how many candidates we have:
if !paths.is_empty() {
if paths.len() == 1 {
session.help(
&format!("you can import it into scope: `use {};`.",
&path_strings[0]),
);
} else {
session.help("you can import several candidates \
into scope (`use ...;`):");
let count = path_strings.len() as isize - MAX_CANDIDATES as isize + 1;
for (idx, path_string) in path_strings.iter().enumerate() {
if idx == MAX_CANDIDATES - 1 && count > 1 {
session.help(
&format!(" and {} other candidates", count).to_string(),
);
break;
} else {
session.help(
&format!(" `{}`", path_string).to_string(),
);
}
}
}
}
} else {
// nothing found:
session.help(
&format!("no candidates by the name of `{}` found in your \
project; maybe you misspelled the name or forgot to import \
an external crate?", candidates.name.to_string()),
);
};
}
/// 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 }