// 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 or the MIT license // , 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(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::FallbackSuggestion::*; use self::TypeParameters::*; use self::RibKind::*; use rustc::hir::map::{Definitions, DefCollector}; use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr}; use rustc::middle::cstore::CrateLoader; use rustc::session::Session; use rustc::lint; use rustc::hir::def::*; use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, 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::ext::base::Determinacy::{Determined, Undetermined}; 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, } 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> { 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; #[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 { value_ns: T, type_ns: T, macro_ns: Option, } impl ::std::ops::Index for PerNS { 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 ::std::ops::IndexMut for PerNS { fn index_mut(&mut self, ns: Namespace) -> &mut T { match ns { ValueNS => &mut self.value_ns, TypeNS => &mut self.type_ns, MacroNS => self.macro_ns.as_mut().unwrap(), } } } impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> { fn visit_item(&mut self, item: &'tcx Item) { self.resolve_item(item); } fn visit_arm(&mut self, arm: &'tcx Arm) { self.resolve_arm(arm); } fn visit_block(&mut self, block: &'tcx Block) { self.resolve_block(block); } fn visit_expr(&mut self, expr: &'tcx Expr) { self.resolve_expr(expr, None); } fn visit_local(&mut self, local: &'tcx Local) { self.resolve_local(local); } fn visit_ty(&mut self, ty: &'tcx Ty) { self.resolve_type(ty); } fn visit_poly_trait_ref(&mut self, tref: &'tcx ast::PolyTraitRef, m: &'tcx ast::TraitBoundModifier) { let ast::Path { ref segments, span, global } = tref.trait_ref.path; let path: Vec<_> = segments.iter().map(|seg| seg.identifier).collect(); let def = self.resolve_trait_reference(&path, global, None, span); self.record_def(tref.trait_ref.ref_id, def); visit::walk_poly_trait_ref(self, tref, m); } fn visit_variant(&mut self, variant: &'tcx ast::Variant, generics: &'tcx Generics, item_id: ast::NodeId) { if let Some(ref dis_expr) = variant.node.disr_expr { // resolve the discriminator expr as a constant self.with_constant_rib(|this| { this.visit_expr(dis_expr); }); } // `visit::walk_variant` without the discriminant expression. self.visit_variant_data(&variant.node.data, variant.node.name, generics, item_id, variant.span); } fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) { let type_parameters = match foreign_item.node { ForeignItemKind::Fn(_, ref generics) => { HasTypeParameters(generics, ItemRibKind) } ForeignItemKind::Static(..) => NoTypeParameters, }; self.with_type_parameter_rib(type_parameters, |this| { visit::walk_foreign_item(this, foreign_item); }); } fn visit_fn(&mut self, function_kind: FnKind<'tcx>, declaration: &'tcx FnDecl, _: Span, node_id: NodeId) { let rib_kind = match function_kind { FnKind::ItemFn(_, generics, ..) => { self.visit_generics(generics); ItemRibKind } FnKind::Method(_, sig, _, _) => { self.visit_generics(&sig.generics); MethodRibKind(!sig.decl.has_self()) } FnKind::Closure(_) => ClosureRibKind(node_id), }; // Create a value rib for the function. self.ribs[ValueNS].push(Rib::new(rib_kind)); // Create a label rib for the function. self.label_ribs.push(Rib::new(rib_kind)); // Add each argument to the rib. let mut bindings_list = FxHashMap(); for argument in &declaration.inputs { self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list); self.visit_ty(&argument.ty); debug!("(resolving function) recorded argument"); } visit::walk_fn_ret_ty(self, &declaration.output); // Resolve the function body. match function_kind { FnKind::ItemFn(.., body) | FnKind::Method(.., body) => { self.visit_block(body); } FnKind::Closure(body) => { self.visit_expr(body); } }; debug!("(resolving function) leaving function"); self.label_ribs.pop(); self.ribs[ValueNS].pop(); } } pub type ErrorMessage = Option<(Span, String)>; 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), } /// One local scope. #[derive(Debug)] struct Rib<'a> { bindings: FxHashMap, 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 #[derive(Copy, Clone)] struct LocalDef { ribs: Option<(Namespace, usize)>, def: Def, } enum LexicalScopeBinding<'a> { Item(&'a NameBinding<'a>), Def(Def), } impl<'a> LexicalScopeBinding<'a> { fn item(self) -> Option<&'a NameBinding<'a>> { match self { LexicalScopeBinding::Item(binding) => Some(binding), _ => None, } } } #[derive(Copy, Clone, PartialEq)] enum PathScope { Global, Lexical, Import, } #[derive(Clone)] enum PathResult<'a> { Module(Module<'a>), NonModule(PathResolution), Indeterminate, Failed(String, bool /* is the error from the last segment? */), } enum ModuleKind { Block(NodeId), Def(Def, Name), } /// One node in the tree of modules. pub struct ModuleData<'a> { parent: Option>, kind: ModuleKind, // The node id of the closest normal module (`mod`) ancestor (including this module). normal_ancestor_id: Option, resolutions: RefCell>>>, legacy_macro_resolutions: RefCell>, macro_resolutions: RefCell, PathScope, Span)>>, // Macro invocations that can expand into items in this module. unresolved_invocations: RefCell>, no_implicit_prelude: bool, glob_importers: RefCell>>, globs: RefCell>>, // Used to memoize the traits in this module for faster searches through all traits in scope. traits: RefCell)]>>>, // 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, } pub type Module<'a> = &'a ModuleData<'a>; impl<'a> ModuleData<'a> { fn new(parent: Option>, kind: ModuleKind) -> Self { ModuleData { parent: parent, kind: kind, normal_ancestor_id: None, resolutions: RefCell::new(FxHashMap()), legacy_macro_resolutions: RefCell::new(Vec::new()), macro_resolutions: RefCell::new(Vec::new()), unresolved_invocations: RefCell::new(FxHashSet()), no_implicit_prelude: false, glob_importers: RefCell::new(Vec::new()), globs: RefCell::new((Vec::new())), traits: RefCell::new(None), populated: Cell::new(true), } } fn for_each_child)>(&self, mut f: F) { for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() { name_resolution.borrow().binding.map(|binding| f(ident, ns, binding)); } } fn def(&self) -> Option { match self.kind { ModuleKind::Def(def, _) => Some(def), _ => None, } } fn def_id(&self) -> Option { 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 ModuleData<'a> { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "{:?}", self.def()) } } // Records a possibly-private value, type, or module definition. #[derive(Clone, Debug)] pub struct NameBinding<'a> { kind: NameBindingKind<'a>, expansion: Mark, span: Span, vis: ty::Visibility, } pub trait ToNameBinding<'a> { fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>; } impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> { fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> { self } } #[derive(Clone, Debug)] enum NameBindingKind<'a> { Def(Def), Module(Module<'a>), Import { binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>, used: Cell, }, 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) -> Option> { match self.kind { NameBindingKind::Module(module) => Some(module), NameBindingKind::Import { binding, .. } => binding.module(), _ => None, } } fn def(&self) -> Def { match self.kind { NameBindingKind::Def(def) => def, NameBindingKind::Module(module) => module.def().unwrap(), NameBindingKind::Import { binding, .. } => binding.def(), NameBindingKind::Ambiguity { .. } => Def::Err, } } fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc { match self.kind { NameBindingKind::Import { binding, .. } => binding.get_macro(resolver), NameBindingKind::Ambiguity { b1, .. } => b1.get_macro(resolver), _ => resolver.get_macro(self.def()), } } // 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, } 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>, graph_root: Module<'a>, prelude: Option>, 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>, // 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>>, // The current set of local scopes, for labels. label_ribs: Vec>, // 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, // The idents for the primitive types. primitive_type_table: PrimitiveTypeTable, def_map: DefMap, pub freevars: FreevarMap, freevars_seen: NodeMap>, 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>, extern_crate_roots: FxHashMap<(CrateNum, bool /* MacrosOnly? */), Module<'a>>, pub make_glob_map: bool, // Maps imports to the names of items actually imported (this actually maps // all imports, but only glob imports are actually interesting). pub glob_map: GlobMap, used_imports: FxHashSet<(NodeId, Namespace)>, used_crates: FxHashSet, pub maybe_unused_trait_imports: NodeSet, privacy_errors: Vec>, ambiguity_errors: Vec>, disallowed_shadowing: Vec<&'a LegacyBinding<'a>>, arenas: &'a ResolverArenas<'a>, dummy_binding: &'a NameBinding<'a>, use_extern_macros: bool, // true if `#![feature(use_extern_macros)]` pub exported_macros: Vec, crate_loader: &'a mut CrateLoader, macro_names: FxHashSet, builtin_macros: FxHashMap>, lexical_macro_resolutions: Vec<(Name, &'a Cell>)>, macro_map: FxHashMap>, macro_exports: Vec, // Maps the `Mark` of an expansion to its containing module or block. invocations: FxHashMap>, // Avoid duplicated errors for "name already defined". name_already_seen: FxHashMap, } pub struct ResolverArenas<'a> { modules: arena::TypedArena>, local_modules: RefCell>>, name_bindings: arena::TypedArena>, import_directives: arena::TypedArena>, name_resolutions: arena::TypedArena>>, invocation_data: arena::TypedArena>, legacy_bindings: arena::TypedArena>, } impl<'a> ResolverArenas<'a> { fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> { let module = self.modules.alloc(module); if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) { self.local_modules.borrow_mut().push(module); } module } fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec>> { 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> { 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_hir_path(&mut self, path: &mut hir::Path, is_value: bool) { let namespace = if is_value { ValueNS } else { TypeNS }; let hir::Path { ref segments, span, global, ref mut def } = *path; let path: Vec<_> = segments.iter().map(|seg| Ident::with_empty_ctxt(seg.name)).collect(); let scope = if global { PathScope::Global } else { PathScope::Lexical }; match self.resolve_path(&path, scope, Some(namespace), Some(span)) { PathResult::Module(module) => *def = module.def().unwrap(), PathResult::NonModule(path_res) if path_res.depth == 0 => *def = path_res.base_def, PathResult::NonModule(..) => match self.resolve_path(&path, scope, None, Some(span)) { PathResult::Failed(msg, _) => { resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); } _ => {} }, PathResult::Indeterminate => unreachable!(), PathResult::Failed(msg, _) => { resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); } } } fn get_resolution(&mut self, id: NodeId) -> Option { self.def_map.get(&id).cloned() } fn definitions(&mut self) -> &mut Definitions { &mut self.definitions } } impl<'a> Resolver<'a> { pub fn new(session: &'a Session, krate: &Crate, make_glob_map: MakeGlobMap, crate_loader: &'a mut CrateLoader, arenas: &'a ResolverArenas<'a>) -> Resolver<'a> { let root_def = Def::Mod(DefId::local(CRATE_DEF_INDEX)); let graph_root = arenas.alloc_module(ModuleData { normal_ancestor_id: Some(CRATE_NODE_ID), no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"), ..ModuleData::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(), 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, }), 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>(&mut self, mut f: F) -> PerNS { PerNS { type_ns: f(self, TypeNS), value_ns: f(self, ValueNS), macro_ns: match self.use_extern_macros { true => Some(f(self, MacroNS)), false => None, }, } } /// Entry point to crate resolution. pub fn resolve_crate(&mut self, krate: &Crate) { ImportResolver { resolver: self }.finalize_imports(); self.current_module = self.graph_root; self.finalize_current_module_macro_resolutions(); visit::walk_crate(self, krate); check_unused::check_crate(self, krate); self.report_errors(); self.crate_loader.postprocess(krate); } fn new_module(&self, parent: Module<'a>, kind: ModuleKind, local: bool) -> Module<'a> { self.arenas.alloc_module(ModuleData { normal_ancestor_id: if local { self.current_module.normal_ancestor_id } else { None }, populated: Cell::new(local), ..ModuleData::new(Some(parent), kind) }) } fn record_use(&mut self, ident: Ident, 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().and_then(ModuleData::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, ident); self.record_use(ident, ns, binding, span) } NameBindingKind::Import { .. } => false, NameBindingKind::Ambiguity { b1, b2 } => { self.ambiguity_errors.push(AmbiguityError { span: span, name: ident.name, lexical: false, b1: b1, b2: b2, }); true } _ => false } } fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) { if self.make_glob_map { self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name); } } /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope. /// More specifically, we proceed up the hierarchy of scopes and return the binding for /// `ident` in the first scope that defines it (or None if no scopes define it). /// /// A block's items are above its local variables in the scope hierarchy, regardless of where /// the items are defined in the block. For example, /// ```rust /// fn f() { /// g(); // Since there are no local variables in scope yet, this resolves to the item. /// let g = || {}; /// fn g() {} /// g(); // This resolves to the local variable `g` since it shadows the item. /// } /// ``` /// /// Invariant: This must only be called during main resolution, not during /// import resolution. fn resolve_ident_in_lexical_scope(&mut self, mut ident: Ident, ns: Namespace, record_used: Option) -> Option> { if ns == TypeNS { ident = ident.unhygienize(); } // Walk backwards up the ribs in scope. for i in (0 .. self.ribs[ns].len()).rev() { if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() { // The ident resolves to a type parameter or local variable. return Some(LexicalScopeBinding::Def(if let Some(span) = record_used { self.adjust_local_def(LocalDef { ribs: Some((ns, i)), def: def }, span) } else { def })); } if let ModuleRibKind(module) = self.ribs[ns][i].kind { let item = self.resolve_ident_in_module(module, ident, ns, false, record_used); if let Ok(binding) = item { // The ident resolves to an item. return Some(LexicalScopeBinding::Item(binding)); } if let ModuleKind::Block(..) = module.kind { // We can see through blocks } else if !module.no_implicit_prelude { return self.prelude.and_then(|prelude| { self.resolve_ident_in_module(prelude, ident, ns, false, None).ok() }).map(LexicalScopeBinding::Item) } else { return None; } } if let MacroDefinition(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 } 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(&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 { 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) => { let path: Vec<_> = prefix.segments.iter().map(|seg| seg.identifier).collect(); // Resolve prefix of an import with empty braces (issue #28388) if items.is_empty() && !prefix.segments.is_empty() { let (scope, span) = (PathScope::Import, prefix.span); // FIXME(#38012) This should be a module path, not anything in TypeNS. let result = self.resolve_path(&path, scope, Some(TypeNS), Some(span)); let (def, msg) = match result { PathResult::Module(module) => (module.def().unwrap(), None), PathResult::NonModule(res) if res.depth == 0 => (res.base_def, None), PathResult::NonModule(_) => { // Resolve a module path for better errors match self.resolve_path(&path, scope, None, Some(span)) { PathResult::Failed(msg, _) => (Def::Err, Some(msg)), _ => unreachable!(), } } PathResult::Indeterminate => unreachable!(), PathResult::Failed(msg, _) => (Def::Err, Some(msg)), }; if let Some(msg) = msg { resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); } self.record_def(item.id, PathResolution::new(def)); } } _ => {} } } 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(&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(&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, path: &[Ident], global: bool, generics: Option<&Generics>, span: Span) -> PathResolution { let scope = if global { PathScope::Global } else { PathScope::Lexical }; let def = match self.resolve_path(path, scope, None, Some(span)) { PathResult::Module(module) => Some(module.def().unwrap()), PathResult::NonModule(..) => return err_path_resolution(), PathResult::Failed(msg, false) => { resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); return err_path_resolution(); } _ => match self.resolve_path(path, scope, Some(TypeNS), None) { PathResult::NonModule(path_resolution) => Some(path_resolution.base_def), _ => None, }, }; if let Some(def) = def { if let Def::Trait(_) = def { return PathResolution::new(def); } let mut err = resolve_struct_error(self, span, { ResolutionError::IsNotATrait(&names_to_string(path), def.kind_name()) }); if let Some(generics) = generics { if let Some(span) = generics.span_for_name(&names_to_string(path)) { err.span_label(span, &"type parameter defined here"); } } // If it's a typedef, give a note if let Def::TyAlias(..) = def { err.note(&format!("type aliases cannot be used for traits")); } err.emit(); } else { // find possible candidates let is_trait = |def| match def { Def::Trait(_) => true, _ => false }; let candidates = self.lookup_candidates(path.last().unwrap().name, TypeNS, is_trait); let path = names_to_string(path); resolve_error(self, span, ResolutionError::UndeclaredTraitName(&path, candidates)); } err_path_resolution() } fn with_current_self_type(&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(&mut self, opt_trait_ref: Option<&TraitRef>, f: F, generics: Option<&Generics>) -> T where F: FnOnce(&mut Resolver, Option) -> T { let mut new_val = None; let mut new_id = None; if let Some(trait_ref) = opt_trait_ref { let ast::Path { ref segments, span, global } = trait_ref.path; let path: Vec<_> = segments.iter().map(|seg| seg.identifier).collect(); let path_res = self.resolve_trait_reference(&path, global, generics, span); assert!(path_res.depth == 0); self.record_def(trait_ref.ref_id, path_res); if path_res.base_def != Def::Err { new_val = Some((path_res.base_def.def_id(), trait_ref.clone())); new_id = Some(path_res.base_def.def_id()); } 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(&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, 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(&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) { if let TyKind::Path(ref maybe_qself, ref path) = ty.node { // 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. 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 type_name = path.segments.last().unwrap().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, } }); 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) -> 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(&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 `::A::B` // or `::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 { let error = ResolutionError::PatPathUnresolved(expected_what, path); resolve_error(self, path.span, error); 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) { // Visit all direct subpatterns of this pattern. let outer_pat_id = pat.id; pat.walk(&mut |pat| { match pat.node { PatKind::Ident(bmode, ref ident, ref opt_pat) => { // First try to resolve the identifier as some existing // entity, then fall back to a fresh binding. let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS, None) .and_then(LexicalScopeBinding::item); let resolution = binding.map(NameBinding::def).and_then(|def| { let always_binding = !pat_src.is_refutable() || opt_pat.is_some() || bmode != BindingMode::ByValue(Mutability::Immutable); match def { Def::StructCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Const) | Def::Const(..) if !always_binding => { // A unit struct/variant or constant pattern. self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span); Some(PathResolution::new(def)) } Def::StructCtor(..) | Def::VariantCtor(..) | Def::Const(..) | Def::Static(..) => { // A fresh binding that shadows something unacceptable. resolve_error( self, ident.span, ResolutionError::BindingShadowsSomethingUnacceptable( pat_src.descr(), ident.node.name, binding.unwrap()) ); None } Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => { // These entities are explicitly allowed // to be shadowed by fresh bindings. None } def => { span_bug!(ident.span, "unexpected definition for an \ identifier in pattern: {:?}", def); } } }).unwrap_or_else(|| { self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings) }); self.record_def(pat.id, resolution); } PatKind::TupleStruct(ref path, ..) => { self.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, ns: Namespace) -> Option { let ast::Path { ref segments, global, span } = *path; let path: Vec<_> = segments.iter().map(|seg| seg.identifier).collect(); let scope = if global { PathScope::Global } else { PathScope::Lexical }; if let Some(qself) = maybe_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.len(), }); } // Make sure the trait is valid. self.resolve_trait_reference(&path[..qself.position], global, None, span); } let result = match self.resolve_path(&path, scope, Some(ns), Some(span)) { PathResult::NonModule(path_res) => match path_res.base_def { Def::Trait(..) if maybe_qself.is_some() => return None, _ => path_res, }, PathResult::Module(module) if !module.is_normal() => { PathResolution::new(module.def().unwrap()) } // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we // don't report an error right away, but try to fallback to a primitive type. // So, we are still able to successfully resolve something like // // use std::u8; // bring module u8 in scope // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8 // u8::max_value() // OK, resolves to associated function ::max_value, // // not to non-existent std::u8::max_value // } // // Such behavior is required for backward compatibility. // The same fallback is used when `a` resolves to nothing. PathResult::Module(..) | PathResult::Failed(..) if scope == PathScope::Lexical && (ns == TypeNS || path.len() > 1) && self.primitive_type_table.primitive_types.contains_key(&path[0].name) => { PathResolution { base_def: Def::PrimTy(self.primitive_type_table.primitive_types[&path[0].name]), depth: segments.len() - 1, } } PathResult::Module(module) => PathResolution::new(module.def().unwrap()), PathResult::Failed(msg, false) => { resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); err_path_resolution() } _ => return None, }; if path.len() == 1 || result.base_def == Def::Err { return Some(result); } let unqualified_result = { match self.resolve_path(&[*path.last().unwrap()], PathScope::Lexical, Some(ns), None) { PathResult::NonModule(path_res) => path_res.base_def, PathResult::Module(module) => module.def().unwrap(), _ => return Some(result), } }; if result.base_def == unqualified_result && path[0].name != "$crate" { let lint = lint::builtin::UNUSED_QUALIFICATIONS; self.session.add_lint(lint, id, span, "unnecessary qualification".to_string()); } Some(result) } fn resolve_path(&mut self, path: &[Ident], scope: PathScope, opt_ns: Option, // `None` indicates a module path record_used: Option) -> PathResult<'a> { let (mut module, allow_self) = match scope { PathScope::Lexical => (None, true), PathScope::Import => (Some(self.graph_root), true), PathScope::Global => (Some(self.graph_root), false), }; let mut allow_super = allow_self; for (i, &ident) in path.iter().enumerate() { let is_last = i == path.len() - 1; let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS }; if i == 0 && allow_self && ns == TypeNS && ident.name == keywords::SelfValue.name() { module = Some(self.module_map[&self.current_module.normal_ancestor_id.unwrap()]); continue } else if i == 0 && allow_self && ns == TypeNS && ident.name == "$crate" { module = Some(self.resolve_crate_var(ident.ctxt)); continue } else if allow_super && ns == TypeNS && ident.name == keywords::Super.name() { let current_module = if i == 0 { self.current_module } else { module.unwrap() }; let self_module = self.module_map[¤t_module.normal_ancestor_id.unwrap()]; if let Some(parent) = self_module.parent { module = Some(self.module_map[&parent.normal_ancestor_id.unwrap()]); continue } else { let msg = "There are too many initial `super`s.".to_string(); return PathResult::Failed(msg, false); } } allow_super = false; let binding = if let Some(module) = module { self.resolve_ident_in_module(module, ident, ns, false, record_used) } else if opt_ns == Some(MacroNS) { self.resolve_lexical_macro_path_segment(ident, ns, record_used) } else { match self.resolve_ident_in_lexical_scope(ident, ns, record_used) { Some(LexicalScopeBinding::Item(binding)) => Ok(binding), Some(LexicalScopeBinding::Def(def)) if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => { return PathResult::NonModule(PathResolution { base_def: def, depth: path.len() - 1, }); } _ => Err(if record_used.is_some() { Determined } else { Undetermined }), } }; match binding { Ok(binding) => { if let Some(next_module) = binding.module() { module = Some(next_module); } else if binding.def() == Def::Err { return PathResult::NonModule(err_path_resolution()); } else if opt_ns.is_some() && !(opt_ns == Some(MacroNS) && !is_last) { return PathResult::NonModule(PathResolution { base_def: binding.def(), depth: path.len() - i - 1, }); } else { return PathResult::Failed(format!("Not a module `{}`", ident), is_last); } } Err(Undetermined) => return PathResult::Indeterminate, Err(Determined) => { if let Some(module) = module { if opt_ns.is_some() && !module.is_normal() { return PathResult::NonModule(PathResolution { base_def: module.def().unwrap(), depth: path.len() - i, }); } } let msg = if module.and_then(ModuleData::def) == self.graph_root.def() { let is_mod = |def| match def { Def::Mod(..) => true, _ => false }; let mut candidates = self.lookup_candidates(ident.name, TypeNS, is_mod).candidates; candidates.sort_by_key(|path| (path.segments.len(), path.to_string())); if let Some(candidate) = candidates.get(0) { format!("Did you mean `{}`?", candidate) } else { format!("Maybe a missing `extern crate {};`?", ident) } } else if i == 0 { format!("Use of undeclared type or module `{}`", ident) } else { format!("Could not find `{}` in `{}`", ident, path[i - 1]) }; return PathResult::Failed(msg, is_last); } } } PathResult::Module(module.unwrap()) } // Resolve a local definition, potentially adjusting for closures. fn adjust_local_def(&mut self, local_def: LocalDef, span: Span) -> 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 Def::Err; } ConstantItemRibKind => { // Still doesn't deal with upvars resolve_error(self, span, ResolutionError::AttemptToUseNonConstantValueInConstant); return Def::Err; } } } } Def::TyParam(..) | Def::SelfTy(..) => { for rib in ribs { match rib.kind { NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) | ModuleRibKind(..) | MacroDefinition(..) => { // Nothing to do. Continue. } ItemRibKind => { // This was an attempt to use a type parameter outside // its scope. resolve_error(self, span, ResolutionError::TypeParametersFromOuterFunction); return Def::Err; } ConstantItemRibKind => { // see #9186 resolve_error(self, span, ResolutionError::OuterTypeParameterContext); return Def::Err; } } } } _ => {} } return def; } // Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope, // i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`). // FIXME #34673: This needs testing. pub fn with_module_lexical_scope(&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(&mut self, f: F) -> T where F: FnOnce(&mut Resolver<'a>) -> T, { let ribs = replace(&mut self.ribs, PerNS::>::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 { 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 == &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, 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); err.help(&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 ast::Path { ref segments, global, .. } = *path; let path: Vec<_> = segments.iter().map(|seg| seg.identifier).collect(); let scope = if global { PathScope::Global } else { PathScope::Lexical }; let type_res = match self.resolve_path(&path, scope, Some(TypeNS), None) { PathResult::NonModule(type_res) => Some(type_res), _ => None, }; self.record_def(expr.id, err_path_resolution()); if let Some(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); err.help(&msg); err.emit(); } else { // Keep reporting some errors even if they're ignored above. 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 && keywords::SelfValue.name() == &*path_name { let error = ResolutionError::SelfNotAvailableInStaticMethod; resolve_error(self, expr.span, error); } else { let fallback = self.find_fallback_in_self_type(path.last().unwrap().name); let (mut msg, is_field) = match fallback { 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 if let PathResult::Module(module) = self.resolve_path(&path, scope, None, None) { def = module.def().unwrap(); context = UnresolvedNameContext::PathIsMod(parent); } } let error = ResolutionError::UnresolvedName { path: &path_name, message: &msg, context: context, is_static_method: method_scope && is_static, is_field: is_field, def: def, }; resolve_error(self, expr.span, error); } } } 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!"); } } // visit `break` argument if any visit::walk_expr(self, expr); } ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => { self.visit_expr(subexpression); self.ribs[ValueNS].push(Rib::new(NormalRibKind)); self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap()); self.visit_block(if_block); self.ribs[ValueNS].pop(); optional_else.as_ref().map(|expr| self.visit_expr(expr)); } ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block), ExprKind::While(ref subexpression, ref block, label) => { self.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 { debug!("(getting traits containing item) looking for '{}'", name); fn add_trait_info(found_traits: &mut Vec, trait_def_id: DefId, import_id: Option, 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(&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(|ident, 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 ident.name == lookup_name && ns == namespace { if filter_fn(name_binding.def()) { // create the path 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: false, 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 Some(module) = name_binding.module() { // form the path let mut path_segments = path_segments.clone(); path_segments.push(PathSegment { identifier: ident, 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 (segments, span, 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.segments, path.span, id), ast::Visibility::Inherited => { return ty::Visibility::Restricted(self.current_module.normal_ancestor_id.unwrap()); } }; let path: Vec<_> = segments.iter().map(|seg| seg.identifier).collect(); let mut path_resolution = err_path_resolution(); let vis = match self.resolve_path(&path, PathScope::Import, None, Some(span)) { PathResult::Module(module) => { path_resolution = PathResolution::new(module.def().unwrap()); ty::Visibility::Restricted(module.normal_ancestor_id.unwrap()) } PathResult::Failed(msg, _) => { self.session.span_err(span, &format!("failed to resolve module path. {}", msg)); ty::Visibility::Public } _ => 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(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 participle = |binding: &NameBinding| { if binding.is_import() { "imported" } else { "defined" } }; let msg1 = format!("`{}` could resolve to the name {} here", name, participle(b1)); let msg2 = format!("`{}` could also resolve to the name {} here", name, participle(b2)); 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() { format!("consider adding an explicit import of `{}` to disambiguate", name) } else if let Def::Macro(..) = b1.def() { format!("macro-expanded {} do not shadow", if b1.is_import() { "macro imports" } else { "macros" }) } else { format!("macro-expanded {} do not shadow when used in a macro invocation path", if b1.is_import() { "imports" } else { "items" }) }) .emit(); } for &PrivacyError(span, name, binding) in &self.privacy_errors { if !reported_spans.insert(span) { continue } if binding.is_extern_crate() { // Warn when using an inaccessible extern crate. let node_id = match binding.kind { NameBindingKind::Import { directive, .. } => directive.id, _ => unreachable!(), }; let msg = format!("extern crate `{}` is private", name); self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg); } else { let def = binding.def(); self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name)); } } } fn report_shadowing_errors(&mut self) { for (name, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) { self.resolve_legacy_scope(scope, name, true); } let mut reported_errors = FxHashSet(); for binding in replace(&mut self.disallowed_shadowing, Vec::new()) { if self.resolve_legacy_scope(&binding.parent, binding.name, false).is_some() && reported_errors.insert((binding.name, binding.span)) { let msg = format!("`{}` is already in scope", binding.name); self.session.struct_span_err(binding.span, &msg) .note("macro-expanded `macro_rules!`s may not shadow \ existing macros (see RFC 1560)") .emit(); } } } fn report_conflict(&mut self, parent: Module, ident: Ident, ns: Namespace, binding: &NameBinding, old_binding: &NameBinding) { // Error on the second of two conflicting names if old_binding.span.lo > binding.span.lo { return self.report_conflict(parent, ident, ns, old_binding, binding); } let container = match parent.kind { ModuleKind::Def(Def::Mod(_), _) => "module", ModuleKind::Def(Def::Trait(_), _) => "trait", ModuleKind::Block(..) => "block", _ => "enum", }; let (participle, noun) = match old_binding.is_import() { true => ("imported", "import"), false => ("defined", "definition"), }; let (name, span) = (ident.name, binding.span); if let Some(s) = self.name_already_seen.get(&name) { if s == &span { return; } } let msg = { let kind = match (ns, old_binding.module()) { (ValueNS, _) => "a value", (MacroNS, _) => "a macro", (TypeNS, _) if old_binding.is_extern_crate() => "an extern crate", (TypeNS, Some(module)) if module.is_normal() => "a module", (TypeNS, Some(module)) if module.is_trait() => "a trait", (TypeNS, _) => "a type", }; format!("{} named `{}` has already been {} in this {}", kind, name, participle, container) }; let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) { (true, true) => { 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, 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("")); 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::>()) } fn err_path_resolution() -> PathResolution { PathResolution::new(Def::Err) } #[derive(PartialEq,Copy, Clone)] pub enum MakeGlobMap { Yes, No, } __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }