// 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. #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png", html_favicon_url = "https://doc.rust-lang.org/favicon.ico", html_root_url = "https://doc.rust-lang.org/nightly/")] #![feature(crate_visibility_modifier)] #![feature(nll)] #![feature(rustc_diagnostic_macros)] #![feature(slice_sort_by_cached_key)] #[macro_use] extern crate log; #[macro_use] extern crate syntax; extern crate syntax_pos; extern crate rustc_errors as errors; extern crate arena; #[macro_use] extern crate rustc; extern crate rustc_data_structures; extern crate rustc_metadata; pub use rustc::hir::def::{Namespace, PerNS}; use self::TypeParameters::*; use self::RibKind::*; use rustc::hir::map::{Definitions, DefCollector}; use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str}; use rustc::middle::cstore::CrateStore; use rustc::session::Session; use rustc::lint; use rustc::hir::def::*; use rustc::hir::def::Namespace::*; use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId}; use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap}; use rustc::session::config::nightly_options; use rustc::ty; use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap}; use rustc_metadata::creader::CrateLoader; use rustc_metadata::cstore::CStore; use syntax::source_map::SourceMap; use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext}; use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy}; use syntax::ext::base::SyntaxExtension; use syntax::ext::base::Determinacy::{self, Determined, Undetermined}; use syntax::ext::base::MacroKind; use syntax::symbol::{Symbol, keywords}; use syntax::util::lev_distance::find_best_match_for_name; use syntax::visit::{self, FnKind, Visitor}; use syntax::attr; use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind}; use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics}; use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind}; use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path}; use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind}; use syntax::ptr::P; use syntax_pos::{Span, DUMMY_SP, MultiSpan}; use errors::{Applicability, DiagnosticBuilder, DiagnosticId}; use std::cell::{Cell, RefCell}; use std::cmp; use std::collections::BTreeSet; use std::fmt; use std::iter; use std::mem::replace; use rustc_data_structures::sync::Lrc; use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver}; use macros::{InvocationData, LegacyBinding, ParentScope}; // NB: This module needs to be declared first so diagnostics are // registered before they are used. mod diagnostics; mod macros; mod check_unused; mod build_reduced_graph; mod resolve_imports; fn is_known_tool(name: Name) -> bool { ["clippy", "rustfmt"].contains(&&*name.as_str()) } /// A free importable items suggested in case of resolution failure. struct ImportSuggestion { path: Path, } /// A field or associated item from self type suggested in case of resolution failure. enum AssocSuggestion { Field, MethodWithSelf, AssocItem, } #[derive(Eq)] struct BindingError { name: Name, origin: BTreeSet, target: BTreeSet, } impl PartialOrd for BindingError { fn partial_cmp(&self, other: &BindingError) -> Option { Some(self.cmp(other)) } } impl PartialEq for BindingError { fn eq(&self, other: &BindingError) -> bool { self.name == other.name } } impl Ord for BindingError { fn cmp(&self, other: &BindingError) -> cmp::Ordering { self.name.cmp(&other.name) } } enum ResolutionError<'a> { /// error E0401: can't use type parameters from outer function TypeParametersFromOuterFunction(Def), /// error E0403: the name is already used for a type parameter in this type parameter list NameAlreadyUsedInTypeParameterList(Name, &'a Span), /// error E0407: method is not a member of trait MethodNotMemberOfTrait(Name, &'a str), /// error E0437: type is not a member of trait TypeNotMemberOfTrait(Name, &'a str), /// error E0438: const is not a member of trait ConstNotMemberOfTrait(Name, &'a str), /// error E0408: variable `{}` is not bound in all patterns VariableNotBoundInPattern(&'a BindingError), /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm VariableBoundWithDifferentMode(Name, Span), /// error E0415: identifier is bound more than once in this parameter list IdentifierBoundMoreThanOnceInParameterList(&'a str), /// error E0416: identifier is bound more than once in the same pattern IdentifierBoundMoreThanOnceInSamePattern(&'a str), /// error E0426: use of undeclared label UndeclaredLabel(&'a str, Option), /// error E0429: `self` imports are only allowed within a { } list SelfImportsOnlyAllowedWithin, /// error E0430: `self` import can only appear once in the list SelfImportCanOnlyAppearOnceInTheList, /// error E0431: `self` import can only appear in an import list with a non-empty prefix SelfImportOnlyInImportListWithNonEmptyPrefix, /// error E0433: failed to resolve FailedToResolve(&'a str), /// error E0434: can't capture dynamic environment in a fn item CannotCaptureDynamicEnvironmentInFnItem, /// error E0435: attempt to use a non-constant value in a constant AttemptToUseNonConstantValueInConstant, /// error E0530: X bindings cannot shadow Ys BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>), /// error E0128: type parameters with a default cannot use forward declared identifiers ForwardDeclaredTyParam, } /// Combines an error with provided span and emits it /// /// This takes the error provided, combines it with the span and any additional spans inside the /// error and emits it. fn resolve_error<'sess, 'a>(resolver: &'sess Resolver, span: Span, resolution_error: ResolutionError<'a>) { resolve_struct_error(resolver, span, resolution_error).emit(); } fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver, span: Span, resolution_error: ResolutionError<'a>) -> DiagnosticBuilder<'sess> { match resolution_error { ResolutionError::TypeParametersFromOuterFunction(outer_def) => { let mut err = struct_span_err!(resolver.session, span, E0401, "can't use type parameters from outer function"); err.span_label(span, "use of type variable from outer function"); let cm = resolver.session.source_map(); match outer_def { Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => { if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| { resolver.definitions.opt_span(def_id) }) { err.span_label( reduce_impl_span_to_impl_keyword(cm, impl_span), "`Self` type implicitly declared here, by this `impl`", ); } match (maybe_trait_defid, maybe_impl_defid) { (Some(_), None) => { err.span_label(span, "can't use `Self` here"); } (_, Some(_)) => { err.span_label(span, "use a type here instead"); } (None, None) => bug!("`impl` without trait nor type?"), } return err; }, Def::TyParam(typaram_defid) => { if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) { err.span_label(typaram_span, "type variable from outer function"); } }, _ => { bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \ Def::TyParam") } } // Try to retrieve the span of the function signature and generate a new message with // a local type parameter let sugg_msg = "try using a local type parameter instead"; if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) { // Suggest the modification to the user err.span_suggestion_with_applicability( sugg_span, sugg_msg, new_snippet, Applicability::MachineApplicable, ); } else if let Some(sp) = cm.generate_fn_name_span(span) { err.span_label(sp, "try adding a local type parameter in this method instead"); } else { err.help("try using a local type parameter instead"); } err } ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => { let mut err = struct_span_err!(resolver.session, span, E0403, "the name `{}` is already used for a type parameter \ in this type parameter list", name); err.span_label(span, "already used"); err.span_label(first_use_span.clone(), format!("first use of `{}`", name)); err } ResolutionError::MethodNotMemberOfTrait(method, trait_) => { let mut err = struct_span_err!(resolver.session, span, E0407, "method `{}` is not a member of trait `{}`", method, trait_); err.span_label(span, format!("not a member of trait `{}`", trait_)); err } ResolutionError::TypeNotMemberOfTrait(type_, trait_) => { let mut err = struct_span_err!(resolver.session, span, E0437, "type `{}` is not a member of trait `{}`", type_, trait_); err.span_label(span, format!("not a member of trait `{}`", trait_)); err } ResolutionError::ConstNotMemberOfTrait(const_, trait_) => { let mut err = struct_span_err!(resolver.session, span, E0438, "const `{}` is not a member of trait `{}`", const_, trait_); err.span_label(span, format!("not a member of trait `{}`", trait_)); err } ResolutionError::VariableNotBoundInPattern(binding_error) => { let target_sp = binding_error.target.iter().cloned().collect::>(); let msp = MultiSpan::from_spans(target_sp.clone()); let msg = format!("variable `{}` is not bound in all patterns", binding_error.name); let mut err = resolver.session.struct_span_err_with_code( msp, &msg, DiagnosticId::Error("E0408".into()), ); for sp in target_sp { err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name)); } let origin_sp = binding_error.origin.iter().cloned(); for sp in origin_sp { err.span_label(sp, "variable not in all patterns"); } err } ResolutionError::VariableBoundWithDifferentMode(variable_name, first_binding_span) => { let mut err = struct_span_err!(resolver.session, span, E0409, "variable `{}` is bound in inconsistent \ ways within the same match arm", variable_name); err.span_label(span, "bound in different ways"); err.span_label(first_binding_span, "first binding"); err } ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => { let mut err = struct_span_err!(resolver.session, span, E0415, "identifier `{}` is bound more than once in this parameter list", identifier); err.span_label(span, "used as parameter more than once"); err } ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => { let mut err = struct_span_err!(resolver.session, span, E0416, "identifier `{}` is bound more than once in the same pattern", identifier); err.span_label(span, "used in a pattern more than once"); err } ResolutionError::UndeclaredLabel(name, lev_candidate) => { let mut err = struct_span_err!(resolver.session, span, E0426, "use of undeclared label `{}`", name); if let Some(lev_candidate) = lev_candidate { err.span_label(span, format!("did you mean `{}`?", lev_candidate)); } else { err.span_label(span, format!("undeclared label `{}`", name)); } err } ResolutionError::SelfImportsOnlyAllowedWithin => { struct_span_err!(resolver.session, span, E0429, "{}", "`self` imports are only allowed within a { } list") } ResolutionError::SelfImportCanOnlyAppearOnceInTheList => { let mut err = struct_span_err!(resolver.session, span, E0430, "`self` import can only appear once in an import list"); err.span_label(span, "can only appear once in an import list"); err } ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => { let mut err = struct_span_err!(resolver.session, span, E0431, "`self` import can only appear in an import list with \ a non-empty prefix"); err.span_label(span, "can only appear in an import list with a non-empty prefix"); err } ResolutionError::FailedToResolve(msg) => { let mut err = struct_span_err!(resolver.session, span, E0433, "failed to resolve. {}", msg); err.span_label(span, msg); err } ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => { let mut err = struct_span_err!(resolver.session, span, E0434, "{}", "can't capture dynamic environment in a fn item"); err.help("use the `|| { ... }` closure form instead"); err } ResolutionError::AttemptToUseNonConstantValueInConstant => { let mut err = struct_span_err!(resolver.session, span, E0435, "attempt to use a non-constant value in a constant"); err.span_label(span, "non-constant value"); err } ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => { let shadows_what = PathResolution::new(binding.def()).kind_name(); let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s", what_binding, shadows_what); err.span_label(span, format!("cannot be named the same as a {}", shadows_what)); let participle = if binding.is_import() { "imported" } else { "defined" }; let msg = format!("a {} `{}` is {} here", shadows_what, name, participle); err.span_label(binding.span, msg); err } ResolutionError::ForwardDeclaredTyParam => { let mut err = struct_span_err!(resolver.session, span, E0128, "type parameters with a default cannot use \ forward declared identifiers"); err.span_label( span, "defaulted type parameters cannot be forward declared".to_string()); err } } } /// Adjust the impl span so that just the `impl` keyword is taken by removing /// everything after `<` (`"impl Iterator for A {}" -> "impl"`) and /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`) /// /// Attention: The method used is very fragile since it essentially duplicates the work of the /// parser. If you need to use this function or something similar, please consider updating the /// source_map functions and this function to something more robust. fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span { let impl_span = cm.span_until_char(impl_span, '<'); let impl_span = cm.span_until_whitespace(impl_span); impl_span } #[derive(Copy, Clone, Debug)] struct BindingInfo { span: Span, binding_mode: BindingMode, } /// Map from the name in a pattern to its binding mode. type BindingMap = FxHashMap; #[derive(Copy, Clone, PartialEq, Eq, Debug)] enum PatternSource { Match, IfLet, WhileLet, Let, For, FnParam, } impl PatternSource { fn descr(self) -> &'static str { match self { PatternSource::Match => "match binding", PatternSource::IfLet => "if let binding", PatternSource::WhileLet => "while let binding", PatternSource::Let => "let binding", PatternSource::For => "for binding", PatternSource::FnParam => "function parameter", } } } #[derive(Copy, Clone, PartialEq, Eq, Debug)] enum AliasPossibility { No, Maybe, } #[derive(Copy, Clone, Debug)] enum PathSource<'a> { // Type paths `Path`. Type, // Trait paths in bounds or impls. Trait(AliasPossibility), // Expression paths `path`, with optional parent context. Expr(Option<&'a Expr>), // Paths in path patterns `Path`. Pat, // Paths in struct expressions and patterns `Path { .. }`. Struct, // Paths in tuple struct patterns `Path(..)`. TupleStruct, // `m::A::B` in `::B::C`. TraitItem(Namespace), // Path in `pub(path)` Visibility, // Path in `use a::b::{...};` ImportPrefix, } impl<'a> PathSource<'a> { fn namespace(self) -> Namespace { match self { PathSource::Type | PathSource::Trait(_) | PathSource::Struct | PathSource::Visibility | PathSource::ImportPrefix => TypeNS, PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS, PathSource::TraitItem(ns) => ns, } } fn global_by_default(self) -> bool { match self { PathSource::Visibility | PathSource::ImportPrefix => true, PathSource::Type | PathSource::Expr(..) | PathSource::Pat | PathSource::Struct | PathSource::TupleStruct | PathSource::Trait(_) | PathSource::TraitItem(..) => false, } } fn defer_to_typeck(self) -> bool { match self { PathSource::Type | PathSource::Expr(..) | PathSource::Pat | PathSource::Struct | PathSource::TupleStruct => true, PathSource::Trait(_) | PathSource::TraitItem(..) | PathSource::Visibility | PathSource::ImportPrefix => false, } } fn descr_expected(self) -> &'static str { match self { PathSource::Type => "type", PathSource::Trait(_) => "trait", PathSource::Pat => "unit struct/variant or constant", PathSource::Struct => "struct, variant or union type", PathSource::TupleStruct => "tuple struct/variant", PathSource::Visibility => "module", PathSource::ImportPrefix => "module or enum", PathSource::TraitItem(ns) => match ns { TypeNS => "associated type", ValueNS => "method or associated constant", MacroNS => bug!("associated macro"), }, PathSource::Expr(parent) => match parent.map(|p| &p.node) { // "function" here means "anything callable" rather than `Def::Fn`, // this is not precise but usually more helpful than just "value". Some(&ExprKind::Call(..)) => "function", _ => "value", }, } } fn is_expected(self, def: Def) -> bool { match self { PathSource::Type => match def { Def::Struct(..) | Def::Union(..) | Def::Enum(..) | Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true, _ => false, }, PathSource::Trait(AliasPossibility::No) => match def { Def::Trait(..) => true, _ => false, }, PathSource::Trait(AliasPossibility::Maybe) => match def { Def::Trait(..) => true, Def::TraitAlias(..) => true, _ => false, }, PathSource::Expr(..) => match def { Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) | Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) | Def::SelfCtor(..) => true, _ => false, }, PathSource::Pat => match def { Def::StructCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Const) | Def::Const(..) | Def::AssociatedConst(..) | Def::SelfCtor(..) => true, _ => false, }, PathSource::TupleStruct => match def { Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) | Def::SelfCtor(..) => true, _ => false, }, PathSource::Struct => match def { Def::Struct(..) | Def::Union(..) | Def::Variant(..) | Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true, _ => false, }, PathSource::TraitItem(ns) => match def { Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true, Def::AssociatedTy(..) if ns == TypeNS => true, _ => false, }, PathSource::ImportPrefix => match def { Def::Mod(..) | Def::Enum(..) => true, _ => false, }, PathSource::Visibility => match def { Def::Mod(..) => true, _ => false, }, } } fn error_code(self, has_unexpected_resolution: bool) -> &'static str { __diagnostic_used!(E0404); __diagnostic_used!(E0405); __diagnostic_used!(E0412); __diagnostic_used!(E0422); __diagnostic_used!(E0423); __diagnostic_used!(E0425); __diagnostic_used!(E0531); __diagnostic_used!(E0532); __diagnostic_used!(E0573); __diagnostic_used!(E0574); __diagnostic_used!(E0575); __diagnostic_used!(E0576); __diagnostic_used!(E0577); __diagnostic_used!(E0578); match (self, has_unexpected_resolution) { (PathSource::Trait(_), true) => "E0404", (PathSource::Trait(_), false) => "E0405", (PathSource::Type, true) => "E0573", (PathSource::Type, false) => "E0412", (PathSource::Struct, true) => "E0574", (PathSource::Struct, false) => "E0422", (PathSource::Expr(..), true) => "E0423", (PathSource::Expr(..), false) => "E0425", (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532", (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531", (PathSource::TraitItem(..), true) => "E0575", (PathSource::TraitItem(..), false) => "E0576", (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577", (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578", } } } struct UsePlacementFinder { target_module: NodeId, span: Option, found_use: bool, } impl UsePlacementFinder { fn check(krate: &Crate, target_module: NodeId) -> (Option, bool) { let mut finder = UsePlacementFinder { target_module, span: None, found_use: false, }; visit::walk_crate(&mut finder, krate); (finder.span, finder.found_use) } } impl<'tcx> Visitor<'tcx> for UsePlacementFinder { fn visit_mod( &mut self, module: &'tcx ast::Mod, _: Span, _: &[ast::Attribute], node_id: NodeId, ) { if self.span.is_some() { return; } if node_id != self.target_module { visit::walk_mod(self, module); return; } // find a use statement for item in &module.items { match item.node { ItemKind::Use(..) => { // don't suggest placing a use before the prelude // import or other generated ones if item.span.ctxt().outer().expn_info().is_none() { self.span = Some(item.span.shrink_to_lo()); self.found_use = true; return; } }, // don't place use before extern crate ItemKind::ExternCrate(_) => {} // but place them before the first other item _ => if self.span.map_or(true, |span| item.span < span ) { if item.span.ctxt().outer().expn_info().is_none() { // don't insert between attributes and an item if item.attrs.is_empty() { self.span = Some(item.span.shrink_to_lo()); } else { // find the first attribute on the item for attr in &item.attrs { if self.span.map_or(true, |span| attr.span < span) { self.span = Some(attr.span.shrink_to_lo()); } } } } }, } } } } /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes. impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> { fn visit_item(&mut self, item: &'tcx Item) { self.resolve_item(item); } fn visit_arm(&mut self, arm: &'tcx Arm) { self.resolve_arm(arm); } fn visit_block(&mut self, block: &'tcx Block) { self.resolve_block(block); } fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) { self.with_constant_rib(|this| { visit::walk_anon_const(this, constant); }); } fn visit_expr(&mut self, expr: &'tcx Expr) { self.resolve_expr(expr, None); } fn visit_local(&mut self, local: &'tcx Local) { self.resolve_local(local); } fn visit_ty(&mut self, ty: &'tcx Ty) { match ty.node { TyKind::Path(ref qself, ref path) => { self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type); } TyKind::ImplicitSelf => { let self_ty = keywords::SelfType.ident(); let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span) .map_or(Def::Err, |d| d.def()); self.record_def(ty.id, PathResolution::new(def)); } _ => (), } visit::walk_ty(self, ty); } fn visit_poly_trait_ref(&mut self, tref: &'tcx ast::PolyTraitRef, m: &'tcx ast::TraitBoundModifier) { self.smart_resolve_path(tref.trait_ref.ref_id, None, &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe)); visit::walk_poly_trait_ref(self, tref, m); } fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) { let type_parameters = match foreign_item.node { ForeignItemKind::Fn(_, ref generics) => { HasTypeParameters(generics, ItemRibKind) } ForeignItemKind::Static(..) => NoTypeParameters, ForeignItemKind::Ty => NoTypeParameters, ForeignItemKind::Macro(..) => NoTypeParameters, }; self.with_type_parameter_rib(type_parameters, |this| { visit::walk_foreign_item(this, foreign_item); }); } fn visit_fn(&mut self, function_kind: FnKind<'tcx>, declaration: &'tcx FnDecl, _: Span, node_id: NodeId) { let (rib_kind, asyncness) = match function_kind { FnKind::ItemFn(_, ref header, ..) => (ItemRibKind, header.asyncness), FnKind::Method(_, ref sig, _, _) => (TraitOrImplItemRibKind, sig.header.asyncness), FnKind::Closure(_) => // Async closures aren't resolved through `visit_fn`-- they're // processed separately (ClosureRibKind(node_id), IsAsync::NotAsync), }; // Create a value rib for the function. self.ribs[ValueNS].push(Rib::new(rib_kind)); // Create a label rib for the function. self.label_ribs.push(Rib::new(rib_kind)); // Add each argument to the rib. let mut bindings_list = FxHashMap(); for argument in &declaration.inputs { self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list); self.visit_ty(&argument.ty); debug!("(resolving function) recorded argument"); } visit::walk_fn_ret_ty(self, &declaration.output); // Resolve the function body, potentially inside the body of an async closure if let IsAsync::Async { closure_id, .. } = asyncness { let rib_kind = ClosureRibKind(closure_id); self.ribs[ValueNS].push(Rib::new(rib_kind)); self.label_ribs.push(Rib::new(rib_kind)); } match function_kind { FnKind::ItemFn(.., body) | FnKind::Method(.., body) => { self.visit_block(body); } FnKind::Closure(body) => { self.visit_expr(body); } }; // Leave the body of the async closure if asyncness.is_async() { self.label_ribs.pop(); self.ribs[ValueNS].pop(); } debug!("(resolving function) leaving function"); self.label_ribs.pop(); self.ribs[ValueNS].pop(); } fn visit_generics(&mut self, generics: &'tcx Generics) { // For type parameter defaults, we have to ban access // to following type parameters, as the Substs can only // provide previous type parameters as they're built. We // put all the parameters on the ban list and then remove // them one by one as they are processed and become available. let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind); let mut found_default = false; default_ban_rib.bindings.extend(generics.params.iter() .filter_map(|param| match param.kind { GenericParamKind::Lifetime { .. } => None, GenericParamKind::Type { ref default, .. } => { found_default |= default.is_some(); if found_default { Some((Ident::with_empty_ctxt(param.ident.name), Def::Err)) } else { None } } })); for param in &generics.params { match param.kind { GenericParamKind::Lifetime { .. } => self.visit_generic_param(param), GenericParamKind::Type { ref default, .. } => { for bound in ¶m.bounds { self.visit_param_bound(bound); } if let Some(ref ty) = default { self.ribs[TypeNS].push(default_ban_rib); self.visit_ty(ty); default_ban_rib = self.ribs[TypeNS].pop().unwrap(); } // Allow all following defaults to refer to this type parameter. default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name)); } } } for p in &generics.where_clause.predicates { self.visit_where_predicate(p); } } } #[derive(Copy, Clone)] enum TypeParameters<'a, 'b> { NoTypeParameters, HasTypeParameters(// Type parameters. &'b Generics, // The kind of the rib used for type parameters. RibKind<'a>), } /// The rib kind controls the translation of local /// definitions (`Def::Local`) to upvars (`Def::Upvar`). #[derive(Copy, Clone, Debug)] enum RibKind<'a> { /// No translation needs to be applied. NormalRibKind, /// We passed through a closure scope at the given node ID. /// Translate upvars as appropriate. ClosureRibKind(NodeId /* func id */), /// We passed through an impl or trait and are now in one of its /// methods or associated types. Allow references to ty params that impl or trait /// binds. Disallow any other upvars (including other ty params that are /// upvars). TraitOrImplItemRibKind, /// We passed through an item scope. Disallow upvars. ItemRibKind, /// We're in a constant item. Can't refer to dynamic stuff. ConstantItemRibKind, /// We passed through a module. ModuleRibKind(Module<'a>), /// We passed through a `macro_rules!` statement MacroDefinition(DefId), /// All bindings in this rib are type parameters that can't be used /// from the default of a type parameter because they're not declared /// before said type parameter. Also see the `visit_generics` override. ForwardTyParamBanRibKind, } /// One local scope. /// /// A rib represents a scope names can live in. Note that these appear in many places, not just /// around braces. At any place where the list of accessible names (of the given namespace) /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro, /// etc. /// /// Different [rib kinds](enum.RibKind) are transparent for different names. /// /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When /// resolving, the name is looked up from inside out. #[derive(Debug)] struct Rib<'a> { bindings: FxHashMap, kind: RibKind<'a>, } impl<'a> Rib<'a> { fn new(kind: RibKind<'a>) -> Rib<'a> { Rib { bindings: FxHashMap(), kind, } } } /// An intermediate resolution result. /// /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that /// items are visible in their whole block, while defs only from the place they are defined /// forward. enum LexicalScopeBinding<'a> { Item(&'a NameBinding<'a>), Def(Def), } impl<'a> LexicalScopeBinding<'a> { fn item(self) -> Option<&'a NameBinding<'a>> { match self { LexicalScopeBinding::Item(binding) => Some(binding), _ => None, } } fn def(self) -> Def { match self { LexicalScopeBinding::Item(binding) => binding.def(), LexicalScopeBinding::Def(def) => def, } } } #[derive(Copy, Clone, Debug)] pub enum ModuleOrUniformRoot<'a> { /// Regular module. Module(Module<'a>), /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment /// in which external crates resolve, and also `crate` (only in `{{root}}`, /// but *not* `extern`), in the Rust 2018 edition. UniformRoot(Name), } #[derive(Clone, Debug)] enum PathResult<'a> { Module(ModuleOrUniformRoot<'a>), NonModule(PathResolution), Indeterminate, Failed(Span, String, bool /* is the error from the last segment? */), } enum ModuleKind { /// An anonymous module, eg. just a block. /// /// ``` /// fn main() { /// fn f() {} // (1) /// { // This is an anonymous module /// f(); // This resolves to (2) as we are inside the block. /// fn f() {} // (2) /// } /// f(); // Resolves to (1) /// } /// ``` Block(NodeId), /// Any module with a name. /// /// This could be: /// /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`. /// * A trait or an enum (it implicitly contains associated types, methods and variant /// constructors). Def(Def, Name), } /// One node in the tree of modules. pub struct ModuleData<'a> { parent: Option>, kind: ModuleKind, // The def id of the closest normal module (`mod`) ancestor (including this module). normal_ancestor_id: DefId, resolutions: RefCell>>>, legacy_macro_resolutions: RefCell, Option)>>, macro_resolutions: RefCell, Span)>>, builtin_attrs: RefCell)>>, // 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, /// Span of the module itself. Used for error reporting. span: Span, expansion: Mark, } type Module<'a> = &'a ModuleData<'a>; impl<'a> ModuleData<'a> { fn new(parent: Option>, kind: ModuleKind, normal_ancestor_id: DefId, expansion: Mark, span: Span) -> Self { ModuleData { parent, kind, normal_ancestor_id, resolutions: RefCell::new(FxHashMap()), legacy_macro_resolutions: RefCell::new(Vec::new()), macro_resolutions: RefCell::new(Vec::new()), builtin_attrs: RefCell::new(Vec::new()), unresolved_invocations: RefCell::new(FxHashSet()), no_implicit_prelude: false, glob_importers: RefCell::new(Vec::new()), globs: RefCell::new(Vec::new()), traits: RefCell::new(None), populated: Cell::new(normal_ancestor_id.is_local()), span, expansion, } } 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 for_each_child_stable)>(&self, mut f: F) { let resolutions = self.resolutions.borrow(); let mut resolutions = resolutions.iter().collect::>(); resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns)); for &(&(ident, ns), &resolution) in resolutions.iter() { resolution.borrow().binding.map(|binding| f(ident, ns, binding)); } } fn def(&self) -> Option { 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_local() } fn nearest_item_scope(&'a self) -> Module<'a> { if self.is_trait() { self.parent.unwrap() } else { self } } } impl<'a> fmt::Debug for ModuleData<'a> { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "{:?}", self.def()) } } /// Records a possibly-private value, type, or module definition. #[derive(Clone, Debug)] pub struct NameBinding<'a> { kind: NameBindingKind<'a>, expansion: Mark, span: Span, vis: ty::Visibility, } pub trait ToNameBinding<'a> { fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>; } impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> { fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> { self } } #[derive(Clone, Debug)] enum NameBindingKind<'a> { Def(Def, /* is_macro_export */ bool), 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 UseError<'a> { err: DiagnosticBuilder<'a>, /// Attach `use` statements for these candidates candidates: Vec, /// The node id of the module to place the use statements in node_id: NodeId, /// Whether the diagnostic should state that it's "better" better: bool, } struct AmbiguityError<'a> { ident: Ident, 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 def_ignoring_ambiguity(&self) -> Def { match self.kind { NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(), NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(), _ => self.def(), } } fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc { resolver.get_macro(self.def_ignoring_ambiguity()) } // We sometimes need to treat variants as `pub` for backwards compatibility fn pseudo_vis(&self) -> ty::Visibility { if self.is_variant() && self.def().def_id().is_local() { ty::Visibility::Public } else { self.vis } } fn is_variant(&self) -> bool { match self.kind { NameBindingKind::Def(Def::Variant(..), _) | NameBindingKind::Def(Def::VariantCtor(..), _) => true, _ => false, } } fn is_extern_crate(&self) -> bool { match self.kind { NameBindingKind::Import { directive: &ImportDirective { subclass: ImportDirectiveSubclass::ExternCrate(_), .. }, .. } => true, _ => false, } } fn is_import(&self) -> bool { match self.kind { NameBindingKind::Import { .. } => true, _ => false, } } fn is_renamed_extern_crate(&self) -> bool { if let NameBindingKind::Import { directive, ..} = self.kind { if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass { return true; } } false } fn is_glob_import(&self) -> bool { match self.kind { NameBindingKind::Import { directive, .. } => directive.is_glob(), NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(), _ => false, } } fn is_importable(&self) -> bool { match self.def() { Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false, _ => true, } } fn is_macro_def(&self) -> bool { match self.kind { NameBindingKind::Def(Def::Macro(..), _) => true, _ => false, } } fn macro_kind(&self) -> Option { match self.def_ignoring_ambiguity() { Def::Macro(_, kind) => Some(kind), Def::NonMacroAttr(..) => Some(MacroKind::Attr), _ => None, } } fn descr(&self) -> &'static str { if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() } } // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding` // at some expansion round `max(invoc, binding)` when they both emerged from macros. // Then this function returns `true` if `self` may emerge from a macro *after* that // in some later round and screw up our previously found resolution. // See more detailed explanation in // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool { // self > max(invoc, binding) => !(self <= invoc || self <= binding) // Expansions are partially ordered, so "may appear after" is an inversion of // "certainly appears before or simultaneously" and includes unordered cases. let self_parent_expansion = self.expansion; let other_parent_expansion = binding.expansion; let certainly_before_other_or_simultaneously = other_parent_expansion.is_descendant_of(self_parent_expansion); let certainly_before_invoc_or_simultaneously = invoc_parent_expansion.is_descendant_of(self_parent_expansion); !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously) } } /// Interns the names of the primitive types. /// /// All other types are defined somewhere and possibly imported, but the primitive ones need /// special handling, since they have no place of origin. struct PrimitiveTypeTable { primitive_types: FxHashMap, } impl PrimitiveTypeTable { fn new() -> PrimitiveTypeTable { let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() }; table.intern("bool", Bool); table.intern("char", Char); table.intern("f32", Float(FloatTy::F32)); table.intern("f64", Float(FloatTy::F64)); table.intern("isize", Int(IntTy::Isize)); table.intern("i8", Int(IntTy::I8)); table.intern("i16", Int(IntTy::I16)); table.intern("i32", Int(IntTy::I32)); table.intern("i64", Int(IntTy::I64)); table.intern("i128", Int(IntTy::I128)); table.intern("str", Str); table.intern("usize", Uint(UintTy::Usize)); table.intern("u8", Uint(UintTy::U8)); table.intern("u16", Uint(UintTy::U16)); table.intern("u32", Uint(UintTy::U32)); table.intern("u64", Uint(UintTy::U64)); table.intern("u128", Uint(UintTy::U128)); table } fn intern(&mut self, string: &str, primitive_type: PrimTy) { self.primitive_types.insert(Symbol::intern(string), primitive_type); } } /// The main resolver class. /// /// This is the visitor that walks the whole crate. pub struct Resolver<'a, 'b: 'a> { session: &'a Session, cstore: &'a CStore, pub definitions: Definitions, graph_root: Module<'a>, prelude: Option>, /// n.b. This is used only for better diagnostics, not name resolution itself. has_self: FxHashSet, /// 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<(Module<'a>, TraitRef)>, /// The current self type if inside an impl (used for better errors). current_self_type: Option, /// The current self item if inside an ADT (used for better errors). current_self_item: Option, /// The idents for the primitive types. primitive_type_table: PrimitiveTypeTable, def_map: DefMap, import_map: ImportMap, pub freevars: FreevarMap, freevars_seen: NodeMap>, pub export_map: ExportMap, pub trait_map: TraitMap, /// A map from nodes to anonymous modules. /// Anonymous modules are pseudo-modules that are implicitly created around items /// contained within blocks. /// /// For example, if we have this: /// /// fn f() { /// fn g() { /// ... /// } /// } /// /// There will be an anonymous module created around `g` with the ID of the /// entry block for `f`. block_map: NodeMap>, module_map: FxHashMap>, extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>, pub make_glob_map: bool, /// Maps imports to the names of items actually imported (this actually maps /// all imports, but only glob imports are actually interesting). pub glob_map: GlobMap, used_imports: FxHashSet<(NodeId, Namespace)>, pub maybe_unused_trait_imports: NodeSet, pub maybe_unused_extern_crates: Vec<(NodeId, Span)>, /// A list of labels as of yet unused. Labels will be removed from this map when /// they are used (in a `break` or `continue` statement) pub unused_labels: FxHashMap, /// privacy errors are delayed until the end in order to deduplicate them privacy_errors: Vec>, /// ambiguity errors are delayed for deduplication ambiguity_errors: Vec>, /// `use` injections are delayed for better placement and deduplication use_injections: Vec>, /// crate-local macro expanded `macro_export` referred to by a module-relative path macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>, arenas: &'a ResolverArenas<'a>, dummy_binding: &'a NameBinding<'a>, crate_loader: &'a mut CrateLoader<'b>, macro_names: FxHashSet, builtin_macros: FxHashMap>, macro_use_prelude: FxHashMap>, pub all_macros: FxHashMap, macro_map: FxHashMap>, macro_defs: FxHashMap, local_macro_def_scopes: FxHashMap>, pub whitelisted_legacy_custom_derives: Vec, pub found_unresolved_macro: bool, /// List of crate local macros that we need to warn about as being unused. /// Right now this only includes macro_rules! macros, and macros 2.0. unused_macros: FxHashSet, /// 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, potentially_unused_imports: Vec<&'a ImportDirective<'a>>, /// This table maps struct IDs into struct constructor IDs, /// it's not used during normal resolution, only for better error reporting. struct_constructors: DefIdMap<(Def, ty::Visibility)>, /// Only used for better errors on `fn(): fn()` current_type_ascription: Vec, injected_crate: Option>, } /// Nothing really interesting here, it just provides memory for the rest of the crate. 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, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> { fn parent(self, id: DefId) -> Option { match id.krate { LOCAL_CRATE => self.definitions.def_key(id.index).parent, _ => self.cstore.def_key(id).parent, }.map(|index| DefId { index, ..id }) } } /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that /// the resolver is no longer needed as all the relevant information is inline. impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> { fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) { self.resolve_hir_path_cb(path, is_value, |resolver, span, error| resolve_error(resolver, span, error)) } fn resolve_str_path( &mut self, span: Span, crate_root: Option<&str>, components: &[&str], args: Option>, is_value: bool ) -> hir::Path { let mut segments = iter::once(keywords::CrateRoot.ident()) .chain( crate_root.into_iter() .chain(components.iter().cloned()) .map(Ident::from_str) ).map(hir::PathSegment::from_ident).collect::>(); if let Some(args) = args { let ident = segments.last().unwrap().ident; *segments.last_mut().unwrap() = hir::PathSegment { ident, args: Some(args), infer_types: true, }; } let mut path = hir::Path { span, def: Def::Err, segments: segments.into(), }; self.resolve_hir_path(&mut path, is_value); path } fn get_resolution(&mut self, id: NodeId) -> Option { self.def_map.get(&id).cloned() } fn get_import(&mut self, id: NodeId) -> PerNS> { self.import_map.get(&id).cloned().unwrap_or_default() } fn definitions(&mut self) -> &mut Definitions { &mut self.definitions } } impl<'a, 'crateloader> Resolver<'a, 'crateloader> { /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a> /// isn't something that can be returned because it can't be made to live that long, /// and also it's a private type. Fortunately rustdoc doesn't need to know the error, /// just that an error occurred. pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool) -> Result { use std::iter; let mut errored = false; let mut path = if path_str.starts_with("::") { hir::Path { span, def: Def::Err, segments: iter::once(keywords::CrateRoot.ident()).chain({ path_str.split("::").skip(1).map(Ident::from_str) }).map(hir::PathSegment::from_ident).collect(), } } else { hir::Path { span, def: Def::Err, segments: path_str.split("::").map(Ident::from_str) .map(hir::PathSegment::from_ident).collect(), } }; self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true); if errored || path.def == Def::Err { Err(()) } else { Ok(path) } } /// resolve_hir_path, but takes a callback in case there was an error fn resolve_hir_path_cb(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F) where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>) { let namespace = if is_value { ValueNS } else { TypeNS }; let hir::Path { ref segments, span, ref mut def } = *path; let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect(); // FIXME (Manishearth): Intra doc links won't get warned of epoch changes match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) { PathResult::Module(ModuleOrUniformRoot::Module(module)) => *def = module.def().unwrap(), PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => *def = path_res.base_def(), PathResult::NonModule(..) => match self.resolve_path( None, &path, None, true, span, CrateLint::No, ) { PathResult::Failed(span, msg, _) => { error_callback(self, span, ResolutionError::FailedToResolve(&msg)); } _ => {} }, PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) | PathResult::Indeterminate => unreachable!(), PathResult::Failed(span, msg, _) => { error_callback(self, span, ResolutionError::FailedToResolve(&msg)); } } } } impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> { pub fn new(session: &'a Session, cstore: &'a CStore, krate: &Crate, crate_name: &str, make_glob_map: MakeGlobMap, crate_loader: &'a mut CrateLoader<'crateloader>, arenas: &'a ResolverArenas<'a>) -> Resolver<'a, 'crateloader> { let root_def_id = DefId::local(CRATE_DEF_INDEX); let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name()); let graph_root = arenas.alloc_module(ModuleData { no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"), ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span) }); let mut module_map = FxHashMap(); module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root); let mut definitions = Definitions::new(); DefCollector::new(&mut definitions, Mark::root()) .collect_root(crate_name, session.local_crate_disambiguator()); let mut invocations = FxHashMap(); invocations.insert(Mark::root(), arenas.alloc_invocation_data(InvocationData::root(graph_root))); let mut macro_defs = FxHashMap(); macro_defs.insert(Mark::root(), root_def_id); Resolver { session, cstore, definitions, // The outermost module has def ID 0; this is not reflected in the // AST. graph_root, prelude: None, has_self: FxHashSet(), 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: vec![Rib::new(ModuleRibKind(graph_root))], }, label_ribs: Vec::new(), current_trait_ref: None, current_self_type: None, current_self_item: None, primitive_type_table: PrimitiveTypeTable::new(), def_map: NodeMap(), import_map: NodeMap(), freevars: NodeMap(), freevars_seen: NodeMap(), export_map: FxHashMap(), trait_map: NodeMap(), module_map, block_map: NodeMap(), extern_module_map: FxHashMap(), make_glob_map: make_glob_map == MakeGlobMap::Yes, glob_map: NodeMap(), used_imports: FxHashSet(), maybe_unused_trait_imports: NodeSet(), maybe_unused_extern_crates: Vec::new(), unused_labels: FxHashMap(), privacy_errors: Vec::new(), ambiguity_errors: Vec::new(), use_injections: Vec::new(), macro_expanded_macro_export_errors: BTreeSet::new(), arenas, dummy_binding: arenas.alloc_name_binding(NameBinding { kind: NameBindingKind::Def(Def::Err, false), expansion: Mark::root(), span: DUMMY_SP, vis: ty::Visibility::Public, }), crate_loader, macro_names: FxHashSet(), builtin_macros: FxHashMap(), macro_use_prelude: FxHashMap(), all_macros: FxHashMap(), macro_map: FxHashMap(), invocations, macro_defs, local_macro_def_scopes: FxHashMap(), name_already_seen: FxHashMap(), whitelisted_legacy_custom_derives: Vec::new(), potentially_unused_imports: Vec::new(), struct_constructors: DefIdMap(), found_unresolved_macro: false, unused_macros: FxHashSet(), current_type_ascription: Vec::new(), injected_crate: None, } } 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(), } } /// Runs the function on each namespace. fn per_ns(&mut self, mut f: F) { f(self, TypeNS); f(self, ValueNS); f(self, MacroNS); } fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId { loop { match self.macro_defs.get(&ctxt.outer()) { Some(&def_id) => return def_id, None => ctxt.remove_mark(), }; } } /// Entry point to crate resolution. pub fn resolve_crate(&mut self, krate: &Crate) { ImportResolver { resolver: self }.finalize_imports(); self.current_module = self.graph_root; self.finalize_current_module_macro_resolutions(); visit::walk_crate(self, krate); check_unused::check_crate(self, krate); self.report_errors(krate); self.crate_loader.postprocess(krate); } fn new_module( &self, parent: Module<'a>, kind: ModuleKind, normal_ancestor_id: DefId, expansion: Mark, span: Span, ) -> Module<'a> { let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span); self.arenas.alloc_module(module) } fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>) -> bool /* true if an error was reported */ { match binding.kind { NameBindingKind::Import { directive, binding, ref used } if !used.get() => { used.set(true); directive.used.set(true); self.used_imports.insert((directive.id, ns)); self.add_to_glob_map(directive.id, ident); self.record_use(ident, ns, binding) } NameBindingKind::Import { .. } => false, NameBindingKind::Ambiguity { b1, b2 } => { self.ambiguity_errors.push(AmbiguityError { ident, b1, 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_default().insert(ident.name); } } /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope. /// More specifically, we proceed up the hierarchy of scopes and return the binding for /// `ident` in the first scope that defines it (or None if no scopes define it). /// /// A block's items are above its local variables in the scope hierarchy, regardless of where /// the items are defined in the block. For example, /// ```rust /// fn f() { /// g(); // Since there are no local variables in scope yet, this resolves to the item. /// let g = || {}; /// fn g() {} /// g(); // This resolves to the local variable `g` since it shadows the item. /// } /// ``` /// /// Invariant: This must only be called during main resolution, not during /// import resolution. fn resolve_ident_in_lexical_scope(&mut self, mut ident: Ident, ns: Namespace, record_used_id: Option, path_span: Span) -> Option> { let record_used = record_used_id.is_some(); assert!(ns == TypeNS || ns == ValueNS); if ns == TypeNS { ident.span = if ident.name == keywords::SelfType.name() { // FIXME(jseyfried) improve `Self` hygiene ident.span.with_ctxt(SyntaxContext::empty()) } else { ident.span.modern() } } else { ident = ident.modern_and_legacy(); } // Walk backwards up the ribs in scope. let mut module = self.graph_root; for i in (0 .. self.ribs[ns].len()).rev() { if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() { // The ident resolves to a type parameter or local variable. return Some(LexicalScopeBinding::Def( self.adjust_local_def(ns, i, def, record_used, path_span) )); } module = match self.ribs[ns][i].kind { ModuleRibKind(module) => module, MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => { // If an invocation of this macro created `ident`, give up on `ident` // and switch to `ident`'s source from the macro definition. ident.span.remove_mark(); continue } _ => continue, }; let item = self.resolve_ident_in_module_unadjusted( ModuleOrUniformRoot::Module(module), ident, ns, false, record_used, path_span, ); if let Ok(binding) = item { // The ident resolves to an item. return Some(LexicalScopeBinding::Item(binding)); } match module.kind { ModuleKind::Block(..) => {}, // We can see through blocks _ => break, } } ident.span = ident.span.modern(); let mut poisoned = None; loop { let opt_module = if let Some(node_id) = record_used_id { self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span, node_id, &mut poisoned) } else { self.hygienic_lexical_parent(module, &mut ident.span) }; module = unwrap_or!(opt_module, break); let orig_current_module = self.current_module; self.current_module = module; // Lexical resolutions can never be a privacy error. let result = self.resolve_ident_in_module_unadjusted( ModuleOrUniformRoot::Module(module), ident, ns, false, record_used, path_span, ); self.current_module = orig_current_module; match result { Ok(binding) => { if let Some(node_id) = poisoned { self.session.buffer_lint_with_diagnostic( lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK, node_id, ident.span, &format!("cannot find {} `{}` in this scope", ns.descr(), ident), lint::builtin::BuiltinLintDiagnostics:: ProcMacroDeriveResolutionFallback(ident.span), ); } return Some(LexicalScopeBinding::Item(binding)) } Err(Determined) => continue, Err(Undetermined) => span_bug!(ident.span, "undetermined resolution during main resolution pass"), } } if !module.no_implicit_prelude { // `record_used` means that we don't try to load crates during speculative resolution if record_used && ns == TypeNS && self.session.extern_prelude.contains(&ident.name) { let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span); let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX }); self.populate_module_if_necessary(&crate_root); let binding = (crate_root, ty::Visibility::Public, ident.span, Mark::root()).to_name_binding(self.arenas); return Some(LexicalScopeBinding::Item(binding)); } if ns == TypeNS && is_known_tool(ident.name) { let binding = (Def::ToolMod, ty::Visibility::Public, ident.span, Mark::root()).to_name_binding(self.arenas); return Some(LexicalScopeBinding::Item(binding)); } if let Some(prelude) = self.prelude { if let Ok(binding) = self.resolve_ident_in_module_unadjusted( ModuleOrUniformRoot::Module(prelude), ident, ns, false, false, path_span, ) { return Some(LexicalScopeBinding::Item(binding)); } } } None } fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span) -> Option> { if !module.expansion.is_descendant_of(span.ctxt().outer()) { return Some(self.macro_def_scope(span.remove_mark())); } if let ModuleKind::Block(..) = module.kind { return Some(module.parent.unwrap()); } None } fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>, span: &mut Span, node_id: NodeId, poisoned: &mut Option) -> Option> { if let module @ Some(..) = self.hygienic_lexical_parent(module, span) { return module; } // We need to support the next case under a deprecation warning // ``` // struct MyStruct; // ---- begin: this comes from a proc macro derive // mod implementation_details { // // Note that `MyStruct` is not in scope here. // impl SomeTrait for MyStruct { ... } // } // ---- end // ``` // So we have to fall back to the module's parent during lexical resolution in this case. if let Some(parent) = module.parent { // Inner module is inside the macro, parent module is outside of the macro. if module.expansion != parent.expansion && module.expansion.is_descendant_of(parent.expansion) { // The macro is a proc macro derive if module.expansion.looks_like_proc_macro_derive() { if parent.expansion.is_descendant_of(span.ctxt().outer()) { *poisoned = Some(node_id); return module.parent; } } } } None } fn resolve_ident_in_module(&mut self, module: ModuleOrUniformRoot<'a>, mut ident: Ident, ns: Namespace, record_used: bool, span: Span) -> Result<&'a NameBinding<'a>, Determinacy> { ident.span = ident.span.modern(); let orig_current_module = self.current_module; if let ModuleOrUniformRoot::Module(module) = module { if let Some(def) = ident.span.adjust(module.expansion) { self.current_module = self.macro_def_scope(def); } } let result = self.resolve_ident_in_module_unadjusted( module, ident, ns, false, record_used, span, ); self.current_module = orig_current_module; result } fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> { let mut ctxt = ident.span.ctxt(); let mark = if ident.name == keywords::DollarCrate.name() { // When resolving `$crate` from a `macro_rules!` invoked in a `macro`, // we don't want to pretend that the `macro_rules!` definition is in the `macro` // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks. // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!` // definitions actually produced by `macro` and `macro` definitions produced by // `macro_rules!`, but at least such configurations are not stable yet. ctxt = ctxt.modern_and_legacy(); let mut iter = ctxt.marks().into_iter().rev().peekable(); let mut result = None; // Find the last modern mark from the end if it exists. while let Some(&(mark, transparency)) = iter.peek() { if transparency == Transparency::Opaque { result = Some(mark); iter.next(); } else { break; } } // Then find the last legacy mark from the end if it exists. for (mark, transparency) in iter { if transparency == Transparency::SemiTransparent { result = Some(mark); } else { break; } } result } else { ctxt = ctxt.modern(); ctxt.adjust(Mark::root()) }; let module = match mark { Some(def) => self.macro_def_scope(def), None => return self.graph_root, }; self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id }) } fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> { let mut module = self.get_module(module.normal_ancestor_id); while module.span.ctxt().modern() != *ctxt { let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark())); module = self.get_module(parent.normal_ancestor_id); } module } // AST resolution // // We maintain a list of value ribs and type ribs. // // Simultaneously, we keep track of the current position in the module // graph in the `current_module` pointer. When we go to resolve a name in // the value or type namespaces, we first look through all the ribs and // then query the module graph. When we resolve a name in the module // namespace, we can skip all the ribs (since nested modules are not // allowed within blocks in Rust) and jump straight to the current module // graph node. // // Named implementations are handled separately. When we find a method // call, we consult the module node to find all of the implementations in // scope. This information is lazily cached in the module node. We then // generate a fake "implementation scope" containing all the // implementations thus found, for compatibility with old resolve pass. pub fn with_scope(&mut self, id: NodeId, f: F) -> T where F: FnOnce(&mut Resolver) -> T { let id = self.definitions.local_def_id(id); let module = self.module_map.get(&id).cloned(); // clones a reference if let Some(module) = module { // Move down in the graph. let orig_module = replace(&mut self.current_module, module); self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module))); self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module))); self.finalize_current_module_macro_resolutions(); let ret = f(self); self.current_module = orig_module; self.ribs[ValueNS].pop(); self.ribs[TypeNS].pop(); ret } else { f(self) } } /// Searches the current set of local scopes for labels. Returns the first non-None label that /// is returned by the given predicate function /// /// Stops after meeting a closure. fn search_label(&self, mut ident: Ident, pred: P) -> Option where P: Fn(&Rib, Ident) -> Option { for rib in self.label_ribs.iter().rev() { match rib.kind { NormalRibKind => {} // If an invocation of this macro created `ident`, give up on `ident` // and switch to `ident`'s source from the macro definition. MacroDefinition(def) => { if def == self.macro_def(ident.span.ctxt()) { ident.span.remove_mark(); } } _ => { // Do not resolve labels across function boundary return None; } } let r = pred(rib, ident); if r.is_some() { return r; } } None } fn resolve_adt(&mut self, item: &Item, generics: &Generics) { self.with_current_self_item(item, |this| { this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| { let item_def_id = this.definitions.local_def_id(item.id); if this.session.features_untracked().self_in_typedefs { this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| { visit::walk_item(this, item); }); } else { visit::walk_item(this, item); } }); }); } fn resolve_item(&mut self, item: &Item) { let name = item.ident.name; debug!("(resolving item) resolving {}", name); match item.node { ItemKind::Ty(_, ref generics) | ItemKind::Fn(_, _, ref generics, _) | ItemKind::Existential(_, ref generics) => { self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| visit::walk_item(this, item)); } ItemKind::Enum(_, ref generics) | ItemKind::Struct(_, ref generics) | ItemKind::Union(_, ref generics) => { self.resolve_adt(item, generics); } ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) => self.resolve_implementation(generics, opt_trait_ref, &self_type, item.id, impl_items), ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => { // Create a new rib for the trait-wide type parameters. self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| { let local_def_id = this.definitions.local_def_id(item.id); this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| { this.visit_generics(generics); walk_list!(this, visit_param_bound, bounds); for trait_item in trait_items { let type_parameters = HasTypeParameters(&trait_item.generics, TraitOrImplItemRibKind); this.with_type_parameter_rib(type_parameters, |this| { match trait_item.node { TraitItemKind::Const(ref ty, ref default) => { this.visit_ty(ty); // Only impose the restrictions of // ConstRibKind for an actual constant // expression in a provided default. if let Some(ref expr) = *default{ this.with_constant_rib(|this| { this.visit_expr(expr); }); } } TraitItemKind::Method(_, _) => { visit::walk_trait_item(this, trait_item) } TraitItemKind::Type(..) => { visit::walk_trait_item(this, trait_item) } TraitItemKind::Macro(_) => { panic!("unexpanded macro in resolve!") } }; }); } }); }); } ItemKind::TraitAlias(ref generics, ref bounds) => { // Create a new rib for the trait-wide type parameters. self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| { let local_def_id = this.definitions.local_def_id(item.id); this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| { this.visit_generics(generics); walk_list!(this, visit_param_bound, bounds); }); }); } ItemKind::Mod(_) | ItemKind::ForeignMod(_) => { self.with_scope(item.id, |this| { visit::walk_item(this, item); }); } ItemKind::Static(ref ty, _, ref expr) | ItemKind::Const(ref ty, ref expr) => { self.with_item_rib(|this| { this.visit_ty(ty); this.with_constant_rib(|this| { this.visit_expr(expr); }); }); } ItemKind::Use(ref use_tree) => { // Imports are resolved as global by default, add starting root segment. let path = Path { segments: use_tree.prefix.make_root().into_iter().collect(), span: use_tree.span, }; self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path); } ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => { // do nothing, these are just around to be encoded } ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"), } } /// For the most part, use trees are desugared into `ImportDirective` instances /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But /// there is one special case we handle here: an empty nested import like /// `a::{b::{}}`, which desugares into...no import directives. fn resolve_use_tree( &mut self, root_id: NodeId, root_span: Span, id: NodeId, use_tree: &ast::UseTree, prefix: &Path, ) { match use_tree.kind { ast::UseTreeKind::Nested(ref items) => { let path = Path { segments: prefix.segments .iter() .chain(use_tree.prefix.segments.iter()) .cloned() .collect(), span: prefix.span.to(use_tree.prefix.span), }; if items.len() == 0 { // Resolve prefix of an import with empty braces (issue #28388). self.smart_resolve_path_with_crate_lint( id, None, &path, PathSource::ImportPrefix, CrateLint::UsePath { root_id, root_span }, ); } else { for &(ref tree, nested_id) in items { self.resolve_use_tree(root_id, root_span, nested_id, tree, &path); } } } ast::UseTreeKind::Simple(..) => {}, ast::UseTreeKind::Glob => {}, } } 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 param in &generics.params { match param.kind { GenericParamKind::Lifetime { .. } => {} GenericParamKind::Type { .. } => { let ident = param.ident.modern(); debug!("with_type_parameter_rib: {}", param.id); if seen_bindings.contains_key(&ident) { let span = seen_bindings.get(&ident).unwrap(); let err = ResolutionError::NameAlreadyUsedInTypeParameterList( ident.name, span, ); resolve_error(self, param.ident.span, err); } seen_bindings.entry(ident).or_insert(param.ident.span); // Plain insert (no renaming). let def = Def::TyParam(self.definitions.local_def_id(param.id)); function_type_rib.bindings.insert(ident, def); self.record_def(param.id, PathResolution::new(def)); } } } self.ribs[TypeNS].push(function_type_rib); } NoTypeParameters => { // Nothing to do. } } f(self); if let HasTypeParameters(..) = type_parameters { self.ribs[TypeNS].pop(); } } fn with_label_rib(&mut self, f: F) where F: FnOnce(&mut Resolver) { self.label_ribs.push(Rib::new(NormalRibKind)); f(self); self.label_ribs.pop(); } fn with_item_rib(&mut self, f: F) where F: FnOnce(&mut Resolver) { self.ribs[ValueNS].push(Rib::new(ItemRibKind)); self.ribs[TypeNS].push(Rib::new(ItemRibKind)); f(self); self.ribs[TypeNS].pop(); self.ribs[ValueNS].pop(); } fn with_constant_rib(&mut self, f: F) where F: FnOnce(&mut Resolver) { self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind)); self.label_ribs.push(Rib::new(ConstantItemRibKind)); f(self); self.label_ribs.pop(); self.ribs[ValueNS].pop(); } fn with_current_self_type(&mut self, self_type: &Ty, f: F) -> T where F: FnOnce(&mut Resolver) -> T { // Handle nested impls (inside fn bodies) let previous_value = replace(&mut self.current_self_type, Some(self_type.clone())); let result = f(self); self.current_self_type = previous_value; result } fn with_current_self_item(&mut self, self_item: &Item, f: F) -> T where F: FnOnce(&mut Resolver) -> T { let previous_value = replace(&mut self.current_self_item, Some(self_item.id)); let result = f(self); self.current_self_item = previous_value; result } /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`) fn with_optional_trait_ref(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> 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 path: Vec<_> = trait_ref.path.segments.iter() .map(|seg| seg.ident) .collect(); let def = self.smart_resolve_path_fragment( trait_ref.ref_id, None, &path, trait_ref.path.span, PathSource::Trait(AliasPossibility::No), CrateLint::SimplePath(trait_ref.ref_id), ).base_def(); if def != Def::Err { new_id = Some(def.def_id()); let span = trait_ref.path.span; if let PathResult::Module(ModuleOrUniformRoot::Module(module)) = self.resolve_path( None, &path, None, false, span, CrateLint::SimplePath(trait_ref.ref_id), ) { new_val = Some((module, trait_ref.clone())); } } } let original_trait_ref = replace(&mut self.current_trait_ref, new_val); let result = f(self, new_id); self.current_trait_ref = original_trait_ref; result } fn with_self_rib(&mut self, self_def: Def, f: F) where F: FnOnce(&mut Resolver) { let mut self_type_rib = Rib::new(NormalRibKind); // plain insert (no renaming, types are not currently hygienic....) self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def); self.ribs[TypeNS].push(self_type_rib); f(self); self.ribs[TypeNS].pop(); } fn with_self_struct_ctor_rib(&mut self, impl_id: DefId, f: F) where F: FnOnce(&mut Resolver) { let self_def = Def::SelfCtor(impl_id); let mut self_type_rib = Rib::new(NormalRibKind); self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def); self.ribs[ValueNS].push(self_type_rib); f(self); self.ribs[ValueNS].pop(); } fn resolve_implementation(&mut self, generics: &Generics, opt_trait_reference: &Option, self_type: &Ty, item_id: NodeId, impl_items: &[ImplItem]) { // If applicable, create a rib for the type parameters. self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| { // Dummy self type for better errors if `Self` is used in the trait path. this.with_self_rib(Def::SelfTy(None, None), |this| { // Resolve the trait reference, if necessary. this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| { let item_def_id = this.definitions.local_def_id(item_id); this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| { if let Some(trait_ref) = opt_trait_reference.as_ref() { // Resolve type arguments in the trait path. visit::walk_trait_ref(this, trait_ref); } // Resolve the self type. this.visit_ty(self_type); // Resolve the type parameters. this.visit_generics(generics); // Resolve the items within the impl. this.with_current_self_type(self_type, |this| { this.with_self_struct_ctor_rib(item_def_id, |this| { for impl_item in impl_items { this.resolve_visibility(&impl_item.vis); // We also need a new scope for the impl item type parameters. let type_parameters = HasTypeParameters(&impl_item.generics, TraitOrImplItemRibKind); this.with_type_parameter_rib(type_parameters, |this| { use self::ResolutionError::*; match impl_item.node { ImplItemKind::Const(..) => { // If this is a trait impl, ensure the const // exists in trait this.check_trait_item(impl_item.ident, ValueNS, impl_item.span, |n, s| ConstNotMemberOfTrait(n, s)); this.with_constant_rib(|this| visit::walk_impl_item(this, impl_item) ); } ImplItemKind::Method(..) => { // If this is a trait impl, ensure the method // exists in trait this.check_trait_item(impl_item.ident, ValueNS, impl_item.span, |n, s| MethodNotMemberOfTrait(n, s)); visit::walk_impl_item(this, impl_item); } ImplItemKind::Type(ref ty) => { // If this is a trait impl, ensure the type // exists in trait this.check_trait_item(impl_item.ident, TypeNS, impl_item.span, |n, s| TypeNotMemberOfTrait(n, s)); this.visit_ty(ty); } ImplItemKind::Existential(ref bounds) => { // If this is a trait impl, ensure the type // exists in trait this.check_trait_item(impl_item.ident, TypeNS, impl_item.span, |n, s| TypeNotMemberOfTrait(n, s)); for bound in bounds { this.visit_param_bound(bound); } } ImplItemKind::Macro(_) => panic!("unexpanded macro in resolve!"), } }); } }); }); }); }); }); }); } fn check_trait_item(&mut self, ident: Ident, ns: Namespace, span: Span, err: F) where F: FnOnce(Name, &str) -> ResolutionError { // If there is a TraitRef in scope for an impl, then the method must be in the // trait. if let Some((module, _)) = self.current_trait_ref { if self.resolve_ident_in_module( ModuleOrUniformRoot::Module(module), ident, ns, false, span, ).is_err() { let path = &self.current_trait_ref.as_ref().unwrap().1.path; resolve_error(self, span, err(ident.name, &path_names_to_string(path))); } } } fn resolve_local(&mut self, local: &Local) { // Resolve the type. walk_list!(self, visit_ty, &local.ty); // Resolve the initializer. walk_list!(self, visit_expr, &local.init); // Resolve the pattern. self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap()); } // build a map from pattern identifiers to binding-info's. // this is done hygienically. This could arise for a macro // that expands into an or-pattern where one 'x' was from the // user and one 'x' came from the macro. fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap { let mut binding_map = FxHashMap(); pat.walk(&mut |pat| { if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node { if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) { Some(Def::Local(..)) => true, _ => false, } { let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode }; binding_map.insert(ident, binding_info); } } true }); binding_map } // check that all of the arms in an or-pattern have exactly the // same set of bindings, with the same binding modes for each. fn check_consistent_bindings(&mut self, pats: &[P]) { if pats.is_empty() { return; } let mut missing_vars = FxHashMap(); let mut inconsistent_vars = FxHashMap(); for (i, p) in pats.iter().enumerate() { let map_i = self.binding_mode_map(&p); for (j, q) in pats.iter().enumerate() { if i == j { continue; } let map_j = self.binding_mode_map(&q); for (&key, &binding_i) in &map_i { if map_j.len() == 0 { // Account for missing bindings when let binding_error = missing_vars // map_j has none. .entry(key.name) .or_insert(BindingError { name: key.name, origin: BTreeSet::new(), target: BTreeSet::new(), }); binding_error.origin.insert(binding_i.span); binding_error.target.insert(q.span); } for (&key_j, &binding_j) in &map_j { match map_i.get(&key_j) { None => { // missing binding let binding_error = missing_vars .entry(key_j.name) .or_insert(BindingError { name: key_j.name, origin: BTreeSet::new(), target: BTreeSet::new(), }); binding_error.origin.insert(binding_j.span); binding_error.target.insert(p.span); } Some(binding_i) => { // check consistent binding if binding_i.binding_mode != binding_j.binding_mode { inconsistent_vars .entry(key.name) .or_insert((binding_j.span, binding_i.span)); } } } } } } } let mut missing_vars = missing_vars.iter().collect::>(); missing_vars.sort(); for (_, v) in missing_vars { resolve_error(self, *v.origin.iter().next().unwrap(), ResolutionError::VariableNotBoundInPattern(v)); } let mut inconsistent_vars = inconsistent_vars.iter().collect::>(); inconsistent_vars.sort(); for (name, v) in inconsistent_vars { resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1)); } } fn resolve_arm(&mut self, arm: &Arm) { self.ribs[ValueNS].push(Rib::new(NormalRibKind)); let mut bindings_list = FxHashMap(); for pattern in &arm.pats { self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list); } // This has to happen *after* we determine which pat_idents are variants self.check_consistent_bindings(&arm.pats); match arm.guard { Some(ast::Guard::If(ref expr)) => self.visit_expr(expr), _ => {} } self.visit_expr(&arm.body); self.ribs[ValueNS].pop(); } fn resolve_block(&mut self, block: &Block) { debug!("(resolving block) entering block"); // Move down in the graph, if there's an anonymous module rooted here. let orig_module = self.current_module; let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference let mut num_macro_definition_ribs = 0; if let Some(anonymous_module) = anonymous_module { debug!("(resolving block) found anonymous module, moving down"); self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module))); self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module))); self.current_module = anonymous_module; self.finalize_current_module_macro_resolutions(); } else { self.ribs[ValueNS].push(Rib::new(NormalRibKind)); } // Descend into the block. for stmt in &block.stmts { if let ast::StmtKind::Item(ref item) = stmt.node { if let ast::ItemKind::MacroDef(..) = item.node { num_macro_definition_ribs += 1; let def = self.definitions.local_def_id(item.id); self.ribs[ValueNS].push(Rib::new(MacroDefinition(def))); self.label_ribs.push(Rib::new(MacroDefinition(def))); } } self.visit_stmt(stmt); } // Move back up. self.current_module = orig_module; for _ in 0 .. num_macro_definition_ribs { self.ribs[ValueNS].pop(); self.label_ribs.pop(); } self.ribs[ValueNS].pop(); if anonymous_module.is_some() { self.ribs[TypeNS].pop(); } debug!("(resolving block) leaving block"); } fn fresh_binding(&mut self, ident: Ident, pat_id: NodeId, outer_pat_id: NodeId, pat_src: PatternSource, bindings: &mut FxHashMap) -> PathResolution { // Add the binding to the local ribs, if it // doesn't already exist in the bindings map. (We // must not add it if it's in the bindings map // because that breaks the assumptions later // passes make about or-patterns.) let ident = ident.modern_and_legacy(); let mut def = Def::Local(pat_id); match bindings.get(&ident).cloned() { Some(id) if id == outer_pat_id => { // `Variant(a, a)`, error resolve_error( self, ident.span, ResolutionError::IdentifierBoundMoreThanOnceInSamePattern( &ident.as_str()) ); } Some(..) if pat_src == PatternSource::FnParam => { // `fn f(a: u8, a: u8)`, error resolve_error( self, ident.span, ResolutionError::IdentifierBoundMoreThanOnceInParameterList( &ident.as_str()) ); } Some(..) if pat_src == PatternSource::Match || pat_src == PatternSource::IfLet || pat_src == PatternSource::WhileLet => { // `Variant1(a) | Variant2(a)`, ok // Reuse definition from the first `a`. def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident]; } Some(..) => { span_bug!(ident.span, "two bindings with the same name from \ unexpected pattern source {:?}", pat_src); } None => { // A completely fresh binding, add to the lists if it's valid. if ident.name != keywords::Invalid.name() { bindings.insert(ident, outer_pat_id); self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def); } } } PathResolution::new(def) } fn resolve_pattern(&mut self, pat: &Pat, pat_src: PatternSource, // Maps idents to the node ID for the // outermost pattern that binds them. bindings: &mut FxHashMap) { // Visit all direct subpatterns of this pattern. let outer_pat_id = pat.id; pat.walk(&mut |pat| { match pat.node { PatKind::Ident(bmode, ident, ref opt_pat) => { // First try to resolve the identifier as some existing // entity, then fall back to a fresh binding. let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, pat.span) .and_then(LexicalScopeBinding::item); let resolution = binding.map(NameBinding::def).and_then(|def| { let is_syntactic_ambiguity = opt_pat.is_none() && bmode == BindingMode::ByValue(Mutability::Immutable); match def { Def::StructCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Const) | Def::Const(..) if is_syntactic_ambiguity => { // Disambiguate in favor of a unit struct/variant // or constant pattern. self.record_use(ident, ValueNS, binding.unwrap()); Some(PathResolution::new(def)) } Def::StructCtor(..) | Def::VariantCtor(..) | Def::Const(..) | Def::Static(..) => { // This is unambiguously a fresh binding, either syntactically // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves // to something unusable as a pattern (e.g. constructor function), // but we still conservatively report an error, see // issues/33118#issuecomment-233962221 for one reason why. resolve_error( self, ident.span, ResolutionError::BindingShadowsSomethingUnacceptable( pat_src.descr(), ident.name, binding.unwrap()) ); None } Def::Fn(..) | Def::Err => { // These entities are explicitly allowed // to be shadowed by fresh bindings. None } def => { span_bug!(ident.span, "unexpected definition for an \ identifier in pattern: {:?}", def); } } }).unwrap_or_else(|| { self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings) }); self.record_def(pat.id, resolution); } PatKind::TupleStruct(ref path, ..) => { self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct); } PatKind::Path(ref qself, ref path) => { self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat); } PatKind::Struct(ref path, ..) => { self.smart_resolve_path(pat.id, None, path, PathSource::Struct); } _ => {} } true }); visit::walk_pat(self, pat); } // High-level and context dependent path resolution routine. // Resolves the path and records the resolution into definition map. // If resolution fails tries several techniques to find likely // resolution candidates, suggest imports or other help, and report // errors in user friendly way. fn smart_resolve_path(&mut self, id: NodeId, qself: Option<&QSelf>, path: &Path, source: PathSource) -> PathResolution { self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id)) } /// A variant of `smart_resolve_path` where you also specify extra /// information about where the path came from; this extra info is /// sometimes needed for the lint that recommends rewriting /// absolute paths to `crate`, so that it knows how to frame the /// suggestion. If you are just resolving a path like `foo::bar` /// that appears...somewhere, though, then you just want /// `CrateLint::SimplePath`, which is what `smart_resolve_path` /// already provides. fn smart_resolve_path_with_crate_lint( &mut self, id: NodeId, qself: Option<&QSelf>, path: &Path, source: PathSource, crate_lint: CrateLint ) -> PathResolution { let segments = &path.segments.iter() .map(|seg| seg.ident) .collect::>(); self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint) } fn smart_resolve_path_fragment(&mut self, id: NodeId, qself: Option<&QSelf>, path: &[Ident], span: Span, source: PathSource, crate_lint: CrateLint) -> PathResolution { let ident_span = path.last().map_or(span, |ident| ident.span); let ns = source.namespace(); let is_expected = &|def| source.is_expected(def); let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false }; // Base error is amended with one short label and possibly some longer helps/notes. let report_errors = |this: &mut Self, def: Option| { // Make the base error. let expected = source.descr_expected(); let path_str = names_to_string(path); let item_str = path[path.len() - 1]; let code = source.error_code(def.is_some()); let (base_msg, fallback_label, base_span) = if let Some(def) = def { (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str), format!("not a {}", expected), span) } else { let item_span = path[path.len() - 1].span; let (mod_prefix, mod_str) = if path.len() == 1 { (String::new(), "this scope".to_string()) } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() { (String::new(), "the crate root".to_string()) } else { let mod_path = &path[..path.len() - 1]; let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS), false, span, CrateLint::No) { PathResult::Module(ModuleOrUniformRoot::Module(module)) => module.def(), _ => None, }.map_or(String::new(), |def| format!("{} ", def.kind_name())); (mod_prefix, format!("`{}`", names_to_string(mod_path))) }; (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str), format!("not found in {}", mod_str), item_span) }; let code = DiagnosticId::Error(code.into()); let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code); // Emit help message for fake-self from other languages like `this`(javascript) let fake_self: Vec = ["this", "my"].iter().map( |s| Ident::from_str(*s) ).collect(); if fake_self.contains(&item_str) && this.self_value_is_available(path[0].span, span) { err.span_suggestion_with_applicability( span, "did you mean", "self".to_string(), Applicability::MaybeIncorrect, ); } // Emit special messages for unresolved `Self` and `self`. if is_self_type(path, ns) { __diagnostic_used!(E0411); err.code(DiagnosticId::Error("E0411".into())); let available_in = if this.session.features_untracked().self_in_typedefs { "impls, traits, and type definitions" } else { "traits and impls" }; err.span_label(span, format!("`Self` is only available in {}", available_in)); if this.current_self_item.is_some() && nightly_options::is_nightly_build() { err.help("add #![feature(self_in_typedefs)] to the crate attributes \ to enable"); } return (err, Vec::new()); } if is_self_value(path, ns) { __diagnostic_used!(E0424); err.code(DiagnosticId::Error("E0424".into())); err.span_label(span, format!("`self` value is a keyword \ only available in \ methods with `self` parameter")); return (err, Vec::new()); } // Try to lookup the name in more relaxed fashion for better error reporting. let ident = *path.last().unwrap(); let candidates = this.lookup_import_candidates(ident.name, ns, is_expected); if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) { let enum_candidates = this.lookup_import_candidates(ident.name, ns, is_enum_variant); let mut enum_candidates = enum_candidates.iter() .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::>(); enum_candidates.sort(); for (sp, variant_path, enum_path) in enum_candidates { if sp.is_dummy() { let msg = format!("there is an enum variant `{}`, \ try using `{}`?", variant_path, enum_path); err.help(&msg); } else { err.span_suggestion_with_applicability( span, "you can try using the variant's enum", enum_path, Applicability::MachineApplicable, ); } } } if path.len() == 1 && this.self_type_is_available(span) { if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) { let self_is_available = this.self_value_is_available(path[0].span, span); match candidate { AssocSuggestion::Field => { err.span_suggestion_with_applicability( span, "try", format!("self.{}", path_str), Applicability::MachineApplicable, ); if !self_is_available { err.span_label(span, format!("`self` value is a keyword \ only available in \ methods with `self` parameter")); } } AssocSuggestion::MethodWithSelf if self_is_available => { err.span_suggestion_with_applicability( span, "try", format!("self.{}", path_str), Applicability::MachineApplicable, ); } AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => { err.span_suggestion_with_applicability( span, "try", format!("Self::{}", path_str), Applicability::MachineApplicable, ); } } return (err, candidates); } } let mut levenshtein_worked = false; // Try Levenshtein. if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) { err.span_label(ident_span, format!("did you mean `{}`?", candidate)); levenshtein_worked = true; } // Try context dependent help if relaxed lookup didn't work. if let Some(def) = def { match (def, source) { (Def::Macro(..), _) => { err.span_label(span, format!("did you mean `{}!(...)`?", path_str)); return (err, candidates); } (Def::TyAlias(..), PathSource::Trait(_)) => { err.span_label(span, "type aliases cannot be used for traits"); return (err, candidates); } (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node { ExprKind::Field(_, ident) => { err.span_label(parent.span, format!("did you mean `{}::{}`?", path_str, ident)); return (err, candidates); } ExprKind::MethodCall(ref segment, ..) => { err.span_label(parent.span, format!("did you mean `{}::{}(...)`?", path_str, segment.ident)); return (err, candidates); } _ => {} }, (Def::Enum(..), PathSource::TupleStruct) | (Def::Enum(..), PathSource::Expr(..)) => { if let Some(variants) = this.collect_enum_variants(def) { err.note(&format!("did you mean to use one \ of the following variants?\n{}", variants.iter() .map(|suggestion| path_names_to_string(suggestion)) .map(|suggestion| format!("- `{}`", suggestion)) .collect::>() .join("\n"))); } else { err.note("did you mean to use one of the enum's variants?"); } return (err, candidates); }, (Def::Struct(def_id), _) if ns == ValueNS => { if let Some((ctor_def, ctor_vis)) = this.struct_constructors.get(&def_id).cloned() { let accessible_ctor = this.is_accessible(ctor_vis); if is_expected(ctor_def) && !accessible_ctor { err.span_label(span, format!("constructor is not visible \ here due to private fields")); } } else { // HACK(estebank): find a better way to figure out that this was a // parser issue where a struct literal is being used on an expression // where a brace being opened means a block is being started. Look // ahead for the next text to see if `span` is followed by a `{`. let sm = this.session.source_map(); let mut sp = span; loop { sp = sm.next_point(sp); match sm.span_to_snippet(sp) { Ok(ref snippet) => { if snippet.chars().any(|c| { !c.is_whitespace() }) { break; } } _ => break, } } let followed_by_brace = match sm.span_to_snippet(sp) { Ok(ref snippet) if snippet == "{" => true, _ => false, }; match source { PathSource::Expr(Some(parent)) => { match parent.node { ExprKind::MethodCall(ref path_assignment, _) => { err.span_suggestion_with_applicability( sm.start_point(parent.span) .to(path_assignment.ident.span), "use `::` to access an associated function", format!("{}::{}", path_str, path_assignment.ident), Applicability::MaybeIncorrect ); return (err, candidates); }, _ => { err.span_label( span, format!("did you mean `{} {{ /* fields */ }}`?", path_str), ); return (err, candidates); }, } }, PathSource::Expr(None) if followed_by_brace == true => { err.span_label( span, format!("did you mean `({} {{ /* fields */ }})`?", path_str), ); return (err, candidates); }, _ => { err.span_label( span, format!("did you mean `{} {{ /* fields */ }}`?", path_str), ); return (err, candidates); }, } } return (err, candidates); } (Def::Union(..), _) | (Def::Variant(..), _) | (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => { err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?", path_str)); return (err, candidates); } (Def::SelfTy(..), _) if ns == ValueNS => { err.span_label(span, fallback_label); err.note("can't use `Self` as a constructor, you must use the \ implemented struct"); return (err, candidates); } (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => { err.note("can't use a type alias as a constructor"); return (err, candidates); } _ => {} } } // Fallback label. if !levenshtein_worked { err.span_label(base_span, fallback_label); this.type_ascription_suggestion(&mut err, base_span); } (err, candidates) }; let report_errors = |this: &mut Self, def: Option| { let (err, candidates) = report_errors(this, def); let def_id = this.current_module.normal_ancestor_id; let node_id = this.definitions.as_local_node_id(def_id).unwrap(); let better = def.is_some(); this.use_injections.push(UseError { err, candidates, node_id, better }); err_path_resolution() }; let resolution = match self.resolve_qpath_anywhere( id, qself, path, ns, span, source.defer_to_typeck(), source.global_by_default(), crate_lint, ) { Some(resolution) if resolution.unresolved_segments() == 0 => { if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err { resolution } else { // Add a temporary hack to smooth the transition to new struct ctor // visibility rules. See #38932 for more details. let mut res = None; if let Def::Struct(def_id) = resolution.base_def() { if let Some((ctor_def, ctor_vis)) = self.struct_constructors.get(&def_id).cloned() { if is_expected(ctor_def) && self.is_accessible(ctor_vis) { let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY; self.session.buffer_lint(lint, id, span, "private struct constructors are not usable through \ re-exports in outer modules", ); res = Some(PathResolution::new(ctor_def)); } } } res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def()))) } } Some(resolution) if source.defer_to_typeck() => { // Not fully resolved associated item `T::A::B` or `::A::B` // or `::A::B`. If `B` should be resolved in value namespace then // it needs to be added to the trait map. if ns == ValueNS { let item_name = *path.last().unwrap(); let traits = self.get_traits_containing_item(item_name, ns); self.trait_map.insert(id, traits); } resolution } _ => report_errors(self, None) }; if let PathSource::TraitItem(..) = source {} else { // Avoid recording definition of `A::B` in `::B::C`. self.record_def(id, resolution); } resolution } fn type_ascription_suggestion(&self, err: &mut DiagnosticBuilder, base_span: Span) { debug!("type_ascription_suggetion {:?}", base_span); let cm = self.session.source_map(); debug!("self.current_type_ascription {:?}", self.current_type_ascription); if let Some(sp) = self.current_type_ascription.last() { let mut sp = *sp; loop { // try to find the `:`, bail on first non-':'/non-whitespace sp = cm.next_point(sp); if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) { debug!("snippet {:?}", snippet); let line_sp = cm.lookup_char_pos(sp.hi()).line; let line_base_sp = cm.lookup_char_pos(base_span.lo()).line; debug!("{:?} {:?}", line_sp, line_base_sp); if snippet == ":" { err.span_label(base_span, "expecting a type here because of type ascription"); if line_sp != line_base_sp { err.span_suggestion_short_with_applicability( sp, "did you mean to use `;` here instead?", ";".to_string(), Applicability::MaybeIncorrect, ); } break; } else if snippet.trim().len() != 0 { debug!("tried to find type ascription `:` token, couldn't find it"); break; } } else { break; } } } } fn self_type_is_available(&mut self, span: Span) -> bool { let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(), TypeNS, None, span); if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false } } fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool { let ident = Ident::new(keywords::SelfValue.name(), self_span); let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span); if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false } } // Resolve in alternative namespaces if resolution in the primary namespace fails. fn resolve_qpath_anywhere(&mut self, id: NodeId, qself: Option<&QSelf>, path: &[Ident], primary_ns: Namespace, span: Span, defer_to_typeck: bool, global_by_default: bool, crate_lint: CrateLint) -> Option { let mut fin_res = None; // FIXME: can't resolve paths in macro namespace yet, macros are // processed by the little special hack below. for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() { if i == 0 || ns != primary_ns { match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) { // If defer_to_typeck, then resolution > no resolution, // otherwise full resolution > partial resolution > no resolution. Some(res) if res.unresolved_segments() == 0 || defer_to_typeck => return Some(res), res => if fin_res.is_none() { fin_res = res }, }; } } if primary_ns != MacroNS && (self.macro_names.contains(&path[0].modern()) || self.builtin_macros.get(&path[0].name).cloned() .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) || self.macro_use_prelude.get(&path[0].name).cloned() .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) { // Return some dummy definition, it's enough for error reporting. return Some( PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang)) ); } fin_res } /// Handles paths that may refer to associated items. fn resolve_qpath(&mut self, id: NodeId, qself: Option<&QSelf>, path: &[Ident], ns: Namespace, span: Span, global_by_default: bool, crate_lint: CrateLint) -> Option { debug!( "resolve_qpath(id={:?}, qself={:?}, path={:?}, \ ns={:?}, span={:?}, global_by_default={:?})", id, qself, path, ns, span, global_by_default, ); if let Some(qself) = qself { if qself.position == 0 { // This is a case like `::B`, where there is no // trait to resolve. In that case, we leave the `B` // segment to be resolved by type-check. return Some(PathResolution::with_unresolved_segments( Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len() )); } // Make sure `A::B` in `::C` is a trait item. // // Currently, `path` names the full item (`A::B::C`, in // our example). so we extract the prefix of that that is // the trait (the slice upto and including // `qself.position`). And then we recursively resolve that, // but with `qself` set to `None`. // // However, setting `qself` to none (but not changing the // span) loses the information about where this path // *actually* appears, so for the purposes of the crate // lint we pass along information that this is the trait // name from a fully qualified path, and this also // contains the full span (the `CrateLint::QPathTrait`). let ns = if qself.position + 1 == path.len() { ns } else { TypeNS }; let res = self.smart_resolve_path_fragment( id, None, &path[..qself.position + 1], span, PathSource::TraitItem(ns), CrateLint::QPathTrait { qpath_id: id, qpath_span: qself.path_span, }, ); // The remaining segments (the `C` in our example) will // have to be resolved by type-check, since that requires doing // trait resolution. return Some(PathResolution::with_unresolved_segments( res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1 )); } let result = match self.resolve_path( None, &path, Some(ns), true, span, crate_lint, ) { PathResult::NonModule(path_res) => path_res, PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => { PathResolution::new(module.def().unwrap()) } // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we // don't report an error right away, but try to fallback to a primitive type. // So, we are still able to successfully resolve something like // // use std::u8; // bring module u8 in scope // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8 // u8::max_value() // OK, resolves to associated function ::max_value, // // not to non-existent std::u8::max_value // } // // Such behavior is required for backward compatibility. // The same fallback is used when `a` resolves to nothing. PathResult::Module(ModuleOrUniformRoot::Module(_)) | PathResult::Failed(..) if (ns == TypeNS || path.len() > 1) && self.primitive_type_table.primitive_types .contains_key(&path[0].name) => { let prim = self.primitive_type_table.primitive_types[&path[0].name]; PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1) } PathResult::Module(ModuleOrUniformRoot::Module(module)) => PathResolution::new(module.def().unwrap()), PathResult::Failed(span, msg, false) => { resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); err_path_resolution() } PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) | PathResult::Failed(..) => return None, PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"), }; if path.len() > 1 && !global_by_default && result.base_def() != Def::Err && path[0].name != keywords::CrateRoot.name() && path[0].name != keywords::DollarCrate.name() { let unqualified_result = { match self.resolve_path( None, &[*path.last().unwrap()], Some(ns), false, span, CrateLint::No, ) { PathResult::NonModule(path_res) => path_res.base_def(), PathResult::Module(ModuleOrUniformRoot::Module(module)) => module.def().unwrap(), _ => return Some(result), } }; if result.base_def() == unqualified_result { let lint = lint::builtin::UNUSED_QUALIFICATIONS; self.session.buffer_lint(lint, id, span, "unnecessary qualification") } } Some(result) } fn resolve_path( &mut self, base_module: Option>, path: &[Ident], opt_ns: Option, // `None` indicates a module path record_used: bool, path_span: Span, crate_lint: CrateLint, ) -> PathResult<'a> { let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() }; self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope, record_used, path_span, crate_lint) } fn resolve_path_with_parent_scope( &mut self, base_module: Option>, path: &[Ident], opt_ns: Option, // `None` indicates a module path parent_scope: &ParentScope<'a>, record_used: bool, path_span: Span, crate_lint: CrateLint, ) -> PathResult<'a> { let mut module = base_module; let mut allow_super = true; let mut second_binding = None; self.current_module = parent_scope.module; debug!( "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \ path_span={:?}, crate_lint={:?})", path, opt_ns, record_used, path_span, crate_lint, ); for (i, &ident) in path.iter().enumerate() { debug!("resolve_path ident {} {:?}", i, ident); let is_last = i == path.len() - 1; let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS }; let name = ident.name; allow_super &= ns == TypeNS && (name == keywords::SelfValue.name() || name == keywords::Super.name()); if ns == TypeNS { if allow_super && name == keywords::Super.name() { let mut ctxt = ident.span.ctxt().modern(); let self_module = match i { 0 => Some(self.resolve_self(&mut ctxt, self.current_module)), _ => match module { Some(ModuleOrUniformRoot::Module(module)) => Some(module), _ => None, }, }; if let Some(self_module) = self_module { if let Some(parent) = self_module.parent { module = Some(ModuleOrUniformRoot::Module( self.resolve_self(&mut ctxt, parent))); continue; } } let msg = "There are too many initial `super`s.".to_string(); return PathResult::Failed(ident.span, msg, false); } if i == 0 { if name == keywords::SelfValue.name() { let mut ctxt = ident.span.ctxt().modern(); module = Some(ModuleOrUniformRoot::Module( self.resolve_self(&mut ctxt, self.current_module))); continue; } if name == keywords::Extern.name() || name == keywords::CrateRoot.name() && self.session.rust_2018() { module = Some(ModuleOrUniformRoot::UniformRoot(name)); continue; } if name == keywords::CrateRoot.name() || name == keywords::Crate.name() || name == keywords::DollarCrate.name() { // `::a::b`, `crate::a::b` or `$crate::a::b` module = Some(ModuleOrUniformRoot::Module( self.resolve_crate_root(ident))); continue; } } } // Report special messages for path segment keywords in wrong positions. if ident.is_path_segment_keyword() && i != 0 { let name_str = if name == keywords::CrateRoot.name() { "crate root".to_string() } else { format!("`{}`", name) }; let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() { format!("global paths cannot start with {}", name_str) } else { format!("{} in paths can only be used in start position", name_str) }; return PathResult::Failed(ident.span, msg, false); } let binding = if let Some(module) = module { self.resolve_ident_in_module(module, ident, ns, record_used, path_span) } else if opt_ns == Some(MacroNS) { assert!(ns == TypeNS); self.resolve_lexical_macro_path_segment(ident, ns, None, parent_scope, record_used, record_used, path_span).map(|(b, _)| b) } else { let record_used_id = if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None }; match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) { // we found a locally-imported or available item/module Some(LexicalScopeBinding::Item(binding)) => Ok(binding), // we found a local variable or type param Some(LexicalScopeBinding::Def(def)) if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => { return PathResult::NonModule(PathResolution::with_unresolved_segments( def, path.len() - 1 )); } _ => Err(if record_used { Determined } else { Undetermined }), } }; match binding { Ok(binding) => { if i == 1 { second_binding = Some(binding); } let def = binding.def(); let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def); if let Some(next_module) = binding.module() { module = Some(ModuleOrUniformRoot::Module(next_module)); } else if def == Def::ToolMod && i + 1 != path.len() { let def = Def::NonMacroAttr(NonMacroAttrKind::Tool); return PathResult::NonModule(PathResolution::new(def)); } else if def == Def::Err { return PathResult::NonModule(err_path_resolution()); } else if opt_ns.is_some() && (is_last || maybe_assoc) { self.lint_if_path_starts_with_module( crate_lint, path, path_span, second_binding, ); return PathResult::NonModule(PathResolution::with_unresolved_segments( def, path.len() - i - 1 )); } else { return PathResult::Failed(ident.span, format!("Not a module `{}`", ident), is_last); } } Err(Undetermined) => return PathResult::Indeterminate, Err(Determined) => { if let Some(ModuleOrUniformRoot::Module(module)) = module { if opt_ns.is_some() && !module.is_normal() { return PathResult::NonModule(PathResolution::with_unresolved_segments( module.def().unwrap(), path.len() - i )); } } let module_def = match module { Some(ModuleOrUniformRoot::Module(module)) => module.def(), _ => None, }; let msg = if module_def == self.graph_root.def() { let is_mod = |def| match def { Def::Mod(..) => true, _ => false }; let mut candidates = self.lookup_import_candidates(name, TypeNS, is_mod); candidates.sort_by_cached_key(|c| { (c.path.segments.len(), c.path.to_string()) }); if let Some(candidate) = candidates.get(0) { format!("Did you mean `{}`?", candidate.path) } else { format!("Maybe a missing `extern crate {};`?", ident) } } else if i == 0 { format!("Use of undeclared type or module `{}`", ident) } else { format!("Could not find `{}` in `{}`", ident, path[i - 1]) }; return PathResult::Failed(ident.span, msg, is_last); } } } self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding); PathResult::Module(module.unwrap_or_else(|| { span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path); })) } fn lint_if_path_starts_with_module( &self, crate_lint: CrateLint, path: &[Ident], path_span: Span, second_binding: Option<&NameBinding>, ) { // In the 2018 edition this lint is a hard error, so nothing to do if self.session.rust_2018() { return } let (diag_id, diag_span) = match crate_lint { CrateLint::No => return, CrateLint::SimplePath(id) => (id, path_span), CrateLint::UsePath { root_id, root_span } => (root_id, root_span), CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span), }; let first_name = match path.get(0) { Some(ident) => ident.name, None => return, }; // We're only interested in `use` paths which should start with // `{{root}}` or `extern` currently. if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() { return } match path.get(1) { // If this import looks like `crate::...` it's already good Some(ident) if ident.name == keywords::Crate.name() => return, // Otherwise go below to see if it's an extern crate Some(_) => {} // If the path has length one (and it's `CrateRoot` most likely) // then we don't know whether we're gonna be importing a crate or an // item in our crate. Defer this lint to elsewhere None => return, } // If the first element of our path was actually resolved to an // `ExternCrate` (also used for `crate::...`) then no need to issue a // warning, this looks all good! if let Some(binding) = second_binding { if let NameBindingKind::Import { directive: d, .. } = binding.kind { // Careful: we still want to rewrite paths from // renamed extern crates. if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass { return } } } let diag = lint::builtin::BuiltinLintDiagnostics ::AbsPathWithModule(diag_span); self.session.buffer_lint_with_diagnostic( lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, diag_id, diag_span, "absolute paths must start with `self`, `super`, \ `crate`, or an external crate name in the 2018 edition", diag); } // Resolve a local definition, potentially adjusting for closures. fn adjust_local_def(&mut self, ns: Namespace, rib_index: usize, mut def: Def, record_used: bool, span: Span) -> Def { let ribs = &self.ribs[ns][rib_index + 1..]; // An invalid forward use of a type parameter from a previous default. if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind { if record_used { resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam); } assert_eq!(def, Def::Err); return Def::Err; } match def { Def::Upvar(..) => { span_bug!(span, "unexpected {:?} in bindings", def) } Def::Local(node_id) => { for rib in ribs { match rib.kind { NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind => { // Nothing to do. Continue. } ClosureRibKind(function_id) => { let prev_def = def; let seen = self.freevars_seen .entry(function_id) .or_default(); if let Some(&index) = seen.get(&node_id) { def = Def::Upvar(node_id, index, function_id); continue; } let vec = self.freevars .entry(function_id) .or_default(); let depth = vec.len(); def = Def::Upvar(node_id, depth, function_id); if record_used { vec.push(Freevar { def: prev_def, span, }); seen.insert(node_id, depth); } } ItemRibKind | TraitOrImplItemRibKind => { // This was an attempt to access an upvar inside a // named function item. This is not allowed, so we // report an error. if record_used { resolve_error(self, span, ResolutionError::CannotCaptureDynamicEnvironmentInFnItem); } return Def::Err; } ConstantItemRibKind => { // Still doesn't deal with upvars if record_used { resolve_error(self, span, ResolutionError::AttemptToUseNonConstantValueInConstant); } return Def::Err; } } } } Def::TyParam(..) | Def::SelfTy(..) => { for rib in ribs { match rib.kind { NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) | ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind | ConstantItemRibKind => { // Nothing to do. Continue. } ItemRibKind => { // This was an attempt to use a type parameter outside // its scope. if record_used { resolve_error(self, span, ResolutionError::TypeParametersFromOuterFunction(def)); } return Def::Err; } } } } _ => {} } return def; } fn lookup_assoc_candidate(&mut self, ident: Ident, ns: Namespace, filter_fn: FilterFn) -> Option where FilterFn: Fn(Def) -> bool { 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, } } // Fields are generally expected in the same contexts as locals. if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) { if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) { // Look for a field with the same name in the current self_type. if let Some(resolution) = self.def_map.get(&node_id) { match resolution.base_def() { Def::Struct(did) | Def::Union(did) if resolution.unresolved_segments() == 0 => { if let Some(field_names) = self.field_names.get(&did) { if field_names.iter().any(|&field_name| ident.name == field_name) { return Some(AssocSuggestion::Field); } } } _ => {} } } } } // Look for associated items in the current trait. if let Some((module, _)) = self.current_trait_ref { if let Ok(binding) = self.resolve_ident_in_module( ModuleOrUniformRoot::Module(module), ident, ns, false, module.span, ) { let def = binding.def(); if filter_fn(def) { return Some(if self.has_self.contains(&def.def_id()) { AssocSuggestion::MethodWithSelf } else { AssocSuggestion::AssocItem }); } } } None } fn lookup_typo_candidate(&mut self, path: &[Ident], ns: Namespace, filter_fn: FilterFn, span: Span) -> Option where FilterFn: Fn(Def) -> bool { let add_module_candidates = |module: Module, names: &mut Vec| { for (&(ident, _), resolution) in module.resolutions.borrow().iter() { if let Some(binding) = resolution.borrow().binding { if filter_fn(binding.def()) { names.push(ident.name); } } } }; let mut names = Vec::new(); if path.len() == 1 { // Search in lexical scope. // Walk backwards up the ribs in scope and collect candidates. for rib in self.ribs[ns].iter().rev() { // Locals and type parameters for (ident, def) in &rib.bindings { if filter_fn(*def) { names.push(ident.name); } } // Items in scope if let ModuleRibKind(module) = rib.kind { // Items from this module add_module_candidates(module, &mut names); if let ModuleKind::Block(..) = module.kind { // We can see through blocks } else { // Items from the prelude if !module.no_implicit_prelude { names.extend(self.session.extern_prelude.iter().cloned()); if let Some(prelude) = self.prelude { add_module_candidates(prelude, &mut names); } } break; } } } // Add primitive types to the mix if filter_fn(Def::PrimTy(Bool)) { names.extend( self.primitive_type_table.primitive_types.iter().map(|(name, _)| name) ) } } else { // Search in module. let mod_path = &path[..path.len() - 1]; if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS), false, span, CrateLint::No) { if let ModuleOrUniformRoot::Module(module) = module { add_module_candidates(module, &mut names); } } } let name = path[path.len() - 1].name; // Make sure error reporting is deterministic. names.sort_by_cached_key(|name| name.as_str()); match find_best_match_for_name(names.iter(), &name.as_str(), None) { Some(found) if found != name => Some(found), _ => None, } } fn with_resolved_label(&mut self, label: Option