| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| use self::ImportDirectiveSubclass::*; |
| |
| use {AmbiguityError, AmbiguityKind, AmbiguityErrorMisc}; |
| use {CrateLint, Module, ModuleOrUniformRoot, PerNS, ScopeSet, Weak}; |
| use Namespace::{self, TypeNS, MacroNS}; |
| use {NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError}; |
| use {Resolver, Segment}; |
| use {names_to_string, module_to_string}; |
| use {resolve_error, ResolutionError}; |
| use macros::ParentScope; |
| |
| use rustc_data_structures::ptr_key::PtrKey; |
| use rustc::ty; |
| use rustc::lint::builtin::BuiltinLintDiagnostics; |
| use rustc::lint::builtin::{DUPLICATE_MACRO_EXPORTS, PUB_USE_OF_PRIVATE_EXTERN_CRATE}; |
| use rustc::hir::def_id::{CrateNum, DefId}; |
| use rustc::hir::def::*; |
| use rustc::session::DiagnosticMessageId; |
| use rustc::util::nodemap::FxHashSet; |
| |
| use syntax::ast::{Ident, Name, NodeId, CRATE_NODE_ID}; |
| use syntax::ext::base::Determinacy::{self, Determined, Undetermined}; |
| use syntax::ext::hygiene::Mark; |
| use syntax::symbol::keywords; |
| use syntax::util::lev_distance::find_best_match_for_name; |
| use syntax_pos::{MultiSpan, Span}; |
| |
| use std::cell::{Cell, RefCell}; |
| use std::{mem, ptr}; |
| |
| /// Contains data for specific types of import directives. |
| #[derive(Clone, Debug)] |
| pub enum ImportDirectiveSubclass<'a> { |
| SingleImport { |
| target: Ident, |
| source: Ident, |
| result: PerNS<Cell<Result<&'a NameBinding<'a>, Determinacy>>>, |
| type_ns_only: bool, |
| }, |
| GlobImport { |
| is_prelude: bool, |
| max_vis: Cell<ty::Visibility>, // The visibility of the greatest re-export. |
| // n.b. `max_vis` is only used in `finalize_import` to check for re-export errors. |
| }, |
| ExternCrate { |
| source: Option<Name>, |
| target: Ident, |
| }, |
| MacroUse, |
| } |
| |
| /// One import directive. |
| #[derive(Debug,Clone)] |
| crate struct ImportDirective<'a> { |
| /// The id of the `extern crate`, `UseTree` etc that imported this `ImportDirective`. |
| /// |
| /// In the case where the `ImportDirective` was expanded from a "nested" use tree, |
| /// this id is the id of the leaf tree. For example: |
| /// |
| /// ```ignore (pacify the mercilous tidy) |
| /// use foo::bar::{a, b} |
| /// ``` |
| /// |
| /// If this is the import directive for `foo::bar::a`, we would have the id of the `UseTree` |
| /// for `a` in this field. |
| pub id: NodeId, |
| |
| /// The `id` of the "root" use-kind -- this is always the same as |
| /// `id` except in the case of "nested" use trees, in which case |
| /// it will be the `id` of the root use tree. e.g., in the example |
| /// from `id`, this would be the id of the `use foo::bar` |
| /// `UseTree` node. |
| pub root_id: NodeId, |
| |
| /// Span of this use tree. |
| pub span: Span, |
| |
| /// Span of the *root* use tree (see `root_id`). |
| pub root_span: Span, |
| |
| pub parent_scope: ParentScope<'a>, |
| pub module_path: Vec<Segment>, |
| /// The resolution of `module_path`. |
| pub imported_module: Cell<Option<ModuleOrUniformRoot<'a>>>, |
| pub subclass: ImportDirectiveSubclass<'a>, |
| pub vis: Cell<ty::Visibility>, |
| pub used: Cell<bool>, |
| } |
| |
| impl<'a> ImportDirective<'a> { |
| pub fn is_glob(&self) -> bool { |
| match self.subclass { ImportDirectiveSubclass::GlobImport { .. } => true, _ => false } |
| } |
| |
| crate fn crate_lint(&self) -> CrateLint { |
| CrateLint::UsePath { root_id: self.root_id, root_span: self.root_span } |
| } |
| } |
| |
| #[derive(Clone, Default, Debug)] |
| /// Records information about the resolution of a name in a namespace of a module. |
| pub struct NameResolution<'a> { |
| /// Single imports that may define the name in the namespace. |
| /// Import directives are arena-allocated, so it's ok to use pointers as keys. |
| single_imports: FxHashSet<PtrKey<'a, ImportDirective<'a>>>, |
| /// The least shadowable known binding for this name, or None if there are no known bindings. |
| pub binding: Option<&'a NameBinding<'a>>, |
| shadowed_glob: Option<&'a NameBinding<'a>>, |
| } |
| |
| impl<'a> NameResolution<'a> { |
| // Returns the binding for the name if it is known or None if it not known. |
| fn binding(&self) -> Option<&'a NameBinding<'a>> { |
| self.binding.and_then(|binding| { |
| if !binding.is_glob_import() || |
| self.single_imports.is_empty() { Some(binding) } else { None } |
| }) |
| } |
| } |
| |
| impl<'a, 'crateloader> Resolver<'a, 'crateloader> { |
| fn resolution(&self, module: Module<'a>, ident: Ident, ns: Namespace) |
| -> &'a RefCell<NameResolution<'a>> { |
| *module.resolutions.borrow_mut().entry((ident.modern(), ns)) |
| .or_insert_with(|| self.arenas.alloc_name_resolution()) |
| } |
| |
| crate fn resolve_ident_in_module_unadjusted( |
| &mut self, |
| module: ModuleOrUniformRoot<'a>, |
| ident: Ident, |
| ns: Namespace, |
| record_used: bool, |
| path_span: Span, |
| ) -> Result<&'a NameBinding<'a>, Determinacy> { |
| self.resolve_ident_in_module_unadjusted_ext( |
| module, ident, ns, None, false, record_used, path_span |
| ).map_err(|(determinacy, _)| determinacy) |
| } |
| |
| /// Attempts to resolve `ident` in namespaces `ns` of `module`. |
| /// Invariant: if `record_used` is `Some`, expansion and import resolution must be complete. |
| crate fn resolve_ident_in_module_unadjusted_ext( |
| &mut self, |
| module: ModuleOrUniformRoot<'a>, |
| ident: Ident, |
| ns: Namespace, |
| parent_scope: Option<&ParentScope<'a>>, |
| restricted_shadowing: bool, |
| record_used: bool, |
| path_span: Span, |
| ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> { |
| let module = match module { |
| ModuleOrUniformRoot::Module(module) => module, |
| ModuleOrUniformRoot::CrateRootAndExternPrelude => { |
| assert!(!restricted_shadowing); |
| let parent_scope = self.dummy_parent_scope(); |
| let binding = self.early_resolve_ident_in_lexical_scope( |
| ident, ScopeSet::AbsolutePath(ns), &parent_scope, |
| record_used, record_used, path_span, |
| ); |
| return binding.map_err(|determinacy| (determinacy, Weak::No)); |
| } |
| ModuleOrUniformRoot::ExternPrelude => { |
| assert!(!restricted_shadowing); |
| return if ns != TypeNS { |
| Err((Determined, Weak::No)) |
| } else if let Some(binding) = self.extern_prelude_get(ident, !record_used) { |
| Ok(binding) |
| } else if !self.graph_root.unresolved_invocations.borrow().is_empty() { |
| // Macro-expanded `extern crate` items can add names to extern prelude. |
| Err((Undetermined, Weak::No)) |
| } else { |
| Err((Determined, Weak::No)) |
| } |
| } |
| ModuleOrUniformRoot::CurrentScope => { |
| assert!(!restricted_shadowing); |
| let parent_scope = |
| parent_scope.expect("no parent scope for a single-segment import"); |
| |
| if ns == TypeNS { |
| if ident.name == keywords::Crate.name() || |
| ident.name == keywords::DollarCrate.name() { |
| let module = self.resolve_crate_root(ident); |
| let binding = (module, ty::Visibility::Public, |
| module.span, Mark::root()) |
| .to_name_binding(self.arenas); |
| return Ok(binding); |
| } else if ident.name == keywords::Super.name() || |
| ident.name == keywords::SelfValue.name() { |
| // FIXME: Implement these with renaming requirements so that e.g. |
| // `use super;` doesn't work, but `use super as name;` does. |
| // Fall through here to get an error from `early_resolve_...`. |
| } |
| } |
| |
| let binding = self.early_resolve_ident_in_lexical_scope( |
| ident, ScopeSet::Import(ns), parent_scope, record_used, record_used, path_span |
| ); |
| return binding.map_err(|determinacy| (determinacy, Weak::No)); |
| } |
| }; |
| |
| self.populate_module_if_necessary(module); |
| |
| let resolution = self.resolution(module, ident, ns) |
| .try_borrow_mut() |
| .map_err(|_| (Determined, Weak::No))?; // This happens when there is a cycle of imports. |
| |
| if let Some(binding) = resolution.binding { |
| if !restricted_shadowing && binding.expansion != Mark::root() { |
| if let NameBindingKind::Def(_, true) = binding.kind { |
| self.macro_expanded_macro_export_errors.insert((path_span, binding.span)); |
| } |
| } |
| } |
| |
| let check_usable = |this: &mut Self, binding: &'a NameBinding<'a>| { |
| // `extern crate` are always usable for backwards compatibility, see issue #37020, |
| // remove this together with `PUB_USE_OF_PRIVATE_EXTERN_CRATE`. |
| let usable = this.is_accessible(binding.vis) || binding.is_extern_crate(); |
| if usable { Ok(binding) } else { Err((Determined, Weak::No)) } |
| }; |
| |
| if record_used { |
| return resolution.binding.ok_or((Determined, Weak::No)).and_then(|binding| { |
| if self.last_import_segment && check_usable(self, binding).is_err() { |
| Err((Determined, Weak::No)) |
| } else { |
| self.record_use(ident, ns, binding, restricted_shadowing); |
| |
| if let Some(shadowed_glob) = resolution.shadowed_glob { |
| // Forbid expanded shadowing to avoid time travel. |
| if restricted_shadowing && |
| binding.expansion != Mark::root() && |
| binding.def() != shadowed_glob.def() { |
| self.ambiguity_errors.push(AmbiguityError { |
| kind: AmbiguityKind::GlobVsExpanded, |
| ident, |
| b1: binding, |
| b2: shadowed_glob, |
| misc1: AmbiguityErrorMisc::None, |
| misc2: AmbiguityErrorMisc::None, |
| }); |
| } |
| } |
| |
| if !self.is_accessible(binding.vis) && |
| // Remove this together with `PUB_USE_OF_PRIVATE_EXTERN_CRATE` |
| !(self.last_import_segment && binding.is_extern_crate()) { |
| self.privacy_errors.push(PrivacyError(path_span, ident, binding)); |
| } |
| |
| Ok(binding) |
| } |
| }) |
| } |
| |
| // Items and single imports are not shadowable, if we have one, then it's determined. |
| if let Some(binding) = resolution.binding { |
| if !binding.is_glob_import() { |
| return check_usable(self, binding); |
| } |
| } |
| |
| // --- From now on we either have a glob resolution or no resolution. --- |
| |
| // Check if one of single imports can still define the name, |
| // if it can then our result is not determined and can be invalidated. |
| for single_import in &resolution.single_imports { |
| if !self.is_accessible(single_import.vis.get()) { |
| continue; |
| } |
| let module = unwrap_or!(single_import.imported_module.get(), |
| return Err((Undetermined, Weak::No))); |
| let ident = match single_import.subclass { |
| SingleImport { source, .. } => source, |
| _ => unreachable!(), |
| }; |
| match self.resolve_ident_in_module(module, ident, ns, Some(&single_import.parent_scope), |
| false, path_span) { |
| Err(Determined) => continue, |
| Ok(binding) if !self.is_accessible_from( |
| binding.vis, single_import.parent_scope.module |
| ) => continue, |
| Ok(_) | Err(Undetermined) => return Err((Undetermined, Weak::No)), |
| } |
| } |
| |
| // So we have a resolution that's from a glob import. This resolution is determined |
| // if it cannot be shadowed by some new item/import expanded from a macro. |
| // This happens either if there are no unexpanded macros, or expanded names cannot |
| // shadow globs (that happens in macro namespace or with restricted shadowing). |
| // |
| // Additionally, any macro in any module can plant names in the root module if it creates |
| // `macro_export` macros, so the root module effectively has unresolved invocations if any |
| // module has unresolved invocations. |
| // However, it causes resolution/expansion to stuck too often (#53144), so, to make |
| // progress, we have to ignore those potential unresolved invocations from other modules |
| // and prohibit access to macro-expanded `macro_export` macros instead (unless restricted |
| // shadowing is enabled, see `macro_expanded_macro_export_errors`). |
| let unexpanded_macros = !module.unresolved_invocations.borrow().is_empty(); |
| if let Some(binding) = resolution.binding { |
| if !unexpanded_macros || ns == MacroNS || restricted_shadowing { |
| return check_usable(self, binding); |
| } else { |
| return Err((Undetermined, Weak::No)); |
| } |
| } |
| |
| // --- From now on we have no resolution. --- |
| |
| // Now we are in situation when new item/import can appear only from a glob or a macro |
| // expansion. With restricted shadowing names from globs and macro expansions cannot |
| // shadow names from outer scopes, so we can freely fallback from module search to search |
| // in outer scopes. For `early_resolve_ident_in_lexical_scope` to continue search in outer |
| // scopes we return `Undetermined` with `Weak::Yes`. |
| |
| // Check if one of unexpanded macros can still define the name, |
| // if it can then our "no resolution" result is not determined and can be invalidated. |
| if unexpanded_macros { |
| return Err((Undetermined, Weak::Yes)); |
| } |
| |
| // Check if one of glob imports can still define the name, |
| // if it can then our "no resolution" result is not determined and can be invalidated. |
| for glob_import in module.globs.borrow().iter() { |
| if !self.is_accessible(glob_import.vis.get()) { |
| continue |
| } |
| let module = match glob_import.imported_module.get() { |
| Some(ModuleOrUniformRoot::Module(module)) => module, |
| Some(_) => continue, |
| None => return Err((Undetermined, Weak::Yes)), |
| }; |
| let (orig_current_module, mut ident) = (self.current_module, ident.modern()); |
| match ident.span.glob_adjust(module.expansion, glob_import.span.ctxt().modern()) { |
| Some(Some(def)) => self.current_module = self.macro_def_scope(def), |
| Some(None) => {} |
| None => continue, |
| }; |
| let result = self.resolve_ident_in_module_unadjusted( |
| ModuleOrUniformRoot::Module(module), |
| ident, |
| ns, |
| false, |
| path_span, |
| ); |
| self.current_module = orig_current_module; |
| |
| match result { |
| Err(Determined) => continue, |
| Ok(binding) if !self.is_accessible_from( |
| binding.vis, glob_import.parent_scope.module |
| ) => continue, |
| Ok(_) | Err(Undetermined) => return Err((Undetermined, Weak::Yes)), |
| } |
| } |
| |
| // No resolution and no one else can define the name - determinate error. |
| Err((Determined, Weak::No)) |
| } |
| |
| // Add an import directive to the current module. |
| pub fn add_import_directive(&mut self, |
| module_path: Vec<Segment>, |
| subclass: ImportDirectiveSubclass<'a>, |
| span: Span, |
| id: NodeId, |
| root_span: Span, |
| root_id: NodeId, |
| vis: ty::Visibility, |
| parent_scope: ParentScope<'a>) { |
| let current_module = parent_scope.module; |
| let directive = self.arenas.alloc_import_directive(ImportDirective { |
| parent_scope, |
| module_path, |
| imported_module: Cell::new(None), |
| subclass, |
| span, |
| id, |
| root_span, |
| root_id, |
| vis: Cell::new(vis), |
| used: Cell::new(false), |
| }); |
| |
| debug!("add_import_directive({:?})", directive); |
| |
| self.indeterminate_imports.push(directive); |
| match directive.subclass { |
| SingleImport { target, type_ns_only, .. } => { |
| self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS { |
| let mut resolution = this.resolution(current_module, target, ns).borrow_mut(); |
| resolution.single_imports.insert(PtrKey(directive)); |
| }); |
| } |
| // We don't add prelude imports to the globs since they only affect lexical scopes, |
| // which are not relevant to import resolution. |
| GlobImport { is_prelude: true, .. } => {} |
| GlobImport { .. } => current_module.globs.borrow_mut().push(directive), |
| _ => unreachable!(), |
| } |
| } |
| |
| // Given a binding and an import directive that resolves to it, |
| // return the corresponding binding defined by the import directive. |
| crate fn import(&self, binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>) |
| -> &'a NameBinding<'a> { |
| let vis = if binding.pseudo_vis().is_at_least(directive.vis.get(), self) || |
| // c.f. `PUB_USE_OF_PRIVATE_EXTERN_CRATE` |
| !directive.is_glob() && binding.is_extern_crate() { |
| directive.vis.get() |
| } else { |
| binding.pseudo_vis() |
| }; |
| |
| if let GlobImport { ref max_vis, .. } = directive.subclass { |
| if vis == directive.vis.get() || vis.is_at_least(max_vis.get(), self) { |
| max_vis.set(vis) |
| } |
| } |
| |
| self.arenas.alloc_name_binding(NameBinding { |
| kind: NameBindingKind::Import { |
| binding, |
| directive, |
| used: Cell::new(false), |
| }, |
| span: directive.span, |
| vis, |
| expansion: directive.parent_scope.expansion, |
| }) |
| } |
| |
| crate fn check_reserved_macro_name(&self, ident: Ident, ns: Namespace) { |
| // Reserve some names that are not quite covered by the general check |
| // performed on `Resolver::builtin_attrs`. |
| if ns == MacroNS && |
| (ident.name == "cfg" || ident.name == "cfg_attr" || ident.name == "derive") { |
| self.session.span_err(ident.span, |
| &format!("name `{}` is reserved in macro namespace", ident)); |
| } |
| } |
| |
| // Define the name or return the existing binding if there is a collision. |
| pub fn try_define(&mut self, |
| module: Module<'a>, |
| ident: Ident, |
| ns: Namespace, |
| binding: &'a NameBinding<'a>) |
| -> Result<(), &'a NameBinding<'a>> { |
| self.check_reserved_macro_name(ident, ns); |
| self.set_binding_parent_module(binding, module); |
| self.update_resolution(module, ident, ns, |this, resolution| { |
| if let Some(old_binding) = resolution.binding { |
| if binding.def() == Def::Err { |
| // Do not override real bindings with `Def::Err`s from error recovery. |
| return Ok(()); |
| } |
| match (old_binding.is_glob_import(), binding.is_glob_import()) { |
| (true, true) => { |
| if binding.def() != old_binding.def() { |
| resolution.binding = Some(this.ambiguity(AmbiguityKind::GlobVsGlob, |
| old_binding, binding)); |
| } else if !old_binding.vis.is_at_least(binding.vis, &*this) { |
| // We are glob-importing the same item but with greater visibility. |
| resolution.binding = Some(binding); |
| } |
| } |
| (old_glob @ true, false) | (old_glob @ false, true) => { |
| let (glob_binding, nonglob_binding) = if old_glob { |
| (old_binding, binding) |
| } else { |
| (binding, old_binding) |
| }; |
| if glob_binding.def() != nonglob_binding.def() && |
| ns == MacroNS && nonglob_binding.expansion != Mark::root() { |
| resolution.binding = Some(this.ambiguity(AmbiguityKind::GlobVsExpanded, |
| nonglob_binding, glob_binding)); |
| } else { |
| resolution.binding = Some(nonglob_binding); |
| resolution.shadowed_glob = Some(glob_binding); |
| } |
| } |
| (false, false) => { |
| if let (&NameBindingKind::Def(_, true), &NameBindingKind::Def(_, true)) = |
| (&old_binding.kind, &binding.kind) { |
| |
| this.session.buffer_lint_with_diagnostic( |
| DUPLICATE_MACRO_EXPORTS, |
| CRATE_NODE_ID, |
| binding.span, |
| &format!("a macro named `{}` has already been exported", ident), |
| BuiltinLintDiagnostics::DuplicatedMacroExports( |
| ident, old_binding.span, binding.span)); |
| |
| resolution.binding = Some(binding); |
| } else { |
| return Err(old_binding); |
| } |
| } |
| } |
| } else { |
| resolution.binding = Some(binding); |
| } |
| |
| Ok(()) |
| }) |
| } |
| |
| fn ambiguity(&self, kind: AmbiguityKind, b1: &'a NameBinding<'a>, b2: &'a NameBinding<'a>) |
| -> &'a NameBinding<'a> { |
| self.arenas.alloc_name_binding(NameBinding { |
| kind: NameBindingKind::Ambiguity { kind, b1, b2 }, |
| vis: if b1.vis.is_at_least(b2.vis, self) { b1.vis } else { b2.vis }, |
| span: b1.span, |
| expansion: Mark::root(), |
| }) |
| } |
| |
| // Use `f` to mutate the resolution of the name in the module. |
| // If the resolution becomes a success, define it in the module's glob importers. |
| fn update_resolution<T, F>(&mut self, module: Module<'a>, ident: Ident, ns: Namespace, f: F) |
| -> T |
| where F: FnOnce(&mut Resolver<'a, 'crateloader>, &mut NameResolution<'a>) -> T |
| { |
| // Ensure that `resolution` isn't borrowed when defining in the module's glob importers, |
| // during which the resolution might end up getting re-defined via a glob cycle. |
| let (binding, t) = { |
| let resolution = &mut *self.resolution(module, ident, ns).borrow_mut(); |
| let old_binding = resolution.binding(); |
| |
| let t = f(self, resolution); |
| |
| match resolution.binding() { |
| _ if old_binding.is_some() => return t, |
| None => return t, |
| Some(binding) => match old_binding { |
| Some(old_binding) if ptr::eq(old_binding, binding) => return t, |
| _ => (binding, t), |
| } |
| } |
| }; |
| |
| // Define `binding` in `module`s glob importers. |
| for directive in module.glob_importers.borrow_mut().iter() { |
| let mut ident = ident.modern(); |
| let scope = match ident.span.reverse_glob_adjust(module.expansion, |
| directive.span.ctxt().modern()) { |
| Some(Some(def)) => self.macro_def_scope(def), |
| Some(None) => directive.parent_scope.module, |
| None => continue, |
| }; |
| if self.is_accessible_from(binding.vis, scope) { |
| let imported_binding = self.import(binding, directive); |
| let _ = self.try_define(directive.parent_scope.module, ident, ns, imported_binding); |
| } |
| } |
| |
| t |
| } |
| |
| // Define a "dummy" resolution containing a Def::Err as a placeholder for a |
| // failed resolution |
| fn import_dummy_binding(&mut self, directive: &'a ImportDirective<'a>) { |
| if let SingleImport { target, .. } = directive.subclass { |
| let dummy_binding = self.dummy_binding; |
| let dummy_binding = self.import(dummy_binding, directive); |
| self.per_ns(|this, ns| { |
| let _ = this.try_define(directive.parent_scope.module, target, ns, dummy_binding); |
| }); |
| } |
| } |
| } |
| |
| pub struct ImportResolver<'a, 'b: 'a, 'c: 'a + 'b> { |
| pub resolver: &'a mut Resolver<'b, 'c>, |
| } |
| |
| impl<'a, 'b: 'a, 'c: 'a + 'b> ::std::ops::Deref for ImportResolver<'a, 'b, 'c> { |
| type Target = Resolver<'b, 'c>; |
| fn deref(&self) -> &Resolver<'b, 'c> { |
| self.resolver |
| } |
| } |
| |
| impl<'a, 'b: 'a, 'c: 'a + 'b> ::std::ops::DerefMut for ImportResolver<'a, 'b, 'c> { |
| fn deref_mut(&mut self) -> &mut Resolver<'b, 'c> { |
| self.resolver |
| } |
| } |
| |
| impl<'a, 'b: 'a, 'c: 'a + 'b> ty::DefIdTree for &'a ImportResolver<'a, 'b, 'c> { |
| fn parent(self, id: DefId) -> Option<DefId> { |
| self.resolver.parent(id) |
| } |
| } |
| |
| impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> { |
| // Import resolution |
| // |
| // This is a fixed-point algorithm. We resolve imports until our efforts |
| // are stymied by an unresolved import; then we bail out of the current |
| // module and continue. We terminate successfully once no more imports |
| // remain or unsuccessfully when no forward progress in resolving imports |
| // is made. |
| |
| /// Resolves all imports for the crate. This method performs the fixed- |
| /// point iteration. |
| pub fn resolve_imports(&mut self) { |
| let mut prev_num_indeterminates = self.indeterminate_imports.len() + 1; |
| while self.indeterminate_imports.len() < prev_num_indeterminates { |
| prev_num_indeterminates = self.indeterminate_imports.len(); |
| for import in mem::replace(&mut self.indeterminate_imports, Vec::new()) { |
| match self.resolve_import(&import) { |
| true => self.determined_imports.push(import), |
| false => self.indeterminate_imports.push(import), |
| } |
| } |
| } |
| } |
| |
| pub fn finalize_imports(&mut self) { |
| for module in self.arenas.local_modules().iter() { |
| self.finalize_resolutions_in(module); |
| } |
| |
| let mut errors = false; |
| let mut seen_spans = FxHashSet::default(); |
| let mut error_vec = Vec::new(); |
| let mut prev_root_id: NodeId = NodeId::from_u32(0); |
| for i in 0 .. self.determined_imports.len() { |
| let import = self.determined_imports[i]; |
| if let Some((span, err, note)) = self.finalize_import(import) { |
| errors = true; |
| |
| if let SingleImport { source, ref result, .. } = import.subclass { |
| if source.name == "self" { |
| // Silence `unresolved import` error if E0429 is already emitted |
| if let Err(Determined) = result.value_ns.get() { |
| continue; |
| } |
| } |
| } |
| |
| // If the error is a single failed import then create a "fake" import |
| // resolution for it so that later resolve stages won't complain. |
| self.import_dummy_binding(import); |
| if prev_root_id.as_u32() != 0 && |
| prev_root_id.as_u32() != import.root_id.as_u32() && |
| !error_vec.is_empty(){ |
| // in case of new import line, throw diagnostic message |
| // for previous line. |
| let mut empty_vec = vec![]; |
| mem::swap(&mut empty_vec, &mut error_vec); |
| self.throw_unresolved_import_error(empty_vec, None); |
| } |
| if !seen_spans.contains(&span) { |
| let path = import_path_to_string( |
| &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(), |
| &import.subclass, |
| span, |
| ); |
| error_vec.push((span, path, err, note)); |
| seen_spans.insert(span); |
| prev_root_id = import.root_id; |
| } |
| } |
| } |
| |
| if !error_vec.is_empty() { |
| self.throw_unresolved_import_error(error_vec.clone(), None); |
| } |
| |
| // Report unresolved imports only if no hard error was already reported |
| // to avoid generating multiple errors on the same import. |
| if !errors { |
| for import in &self.indeterminate_imports { |
| self.throw_unresolved_import_error(error_vec, Some(MultiSpan::from(import.span))); |
| break; |
| } |
| } |
| } |
| |
| fn throw_unresolved_import_error( |
| &self, |
| error_vec: Vec<(Span, String, String, Option<String>)>, |
| span: Option<MultiSpan>, |
| ) { |
| let max_span_label_msg_count = 10; // upper limit on number of span_label message. |
| let (span, msg, note) = if error_vec.is_empty() { |
| (span.unwrap(), "unresolved import".to_string(), None) |
| } else { |
| let span = MultiSpan::from_spans( |
| error_vec.clone().into_iter() |
| .map(|elem: (Span, String, String, Option<String>)| elem.0) |
| .collect() |
| ); |
| |
| let note: Option<String> = error_vec.clone().into_iter() |
| .filter_map(|elem: (Span, String, String, Option<String>)| elem.3) |
| .last(); |
| |
| let path_vec: Vec<String> = error_vec.clone().into_iter() |
| .map(|elem: (Span, String, String, Option<String>)| format!("`{}`", elem.1)) |
| .collect(); |
| let path = path_vec.join(", "); |
| let msg = format!( |
| "unresolved import{} {}", |
| if path_vec.len() > 1 { "s" } else { "" }, |
| path |
| ); |
| |
| (span, msg, note) |
| }; |
| |
| let mut err = struct_span_err!(self.resolver.session, span, E0432, "{}", &msg); |
| for span_error in error_vec.into_iter().take(max_span_label_msg_count) { |
| err.span_label(span_error.0, span_error.2); |
| } |
| if let Some(note) = note { |
| err.note(¬e); |
| } |
| err.emit(); |
| } |
| |
| /// Attempts to resolve the given import, returning true if its resolution is determined. |
| /// If successful, the resolved bindings are written into the module. |
| fn resolve_import(&mut self, directive: &'b ImportDirective<'b>) -> bool { |
| debug!("(resolving import for module) resolving import `{}::...` in `{}`", |
| Segment::names_to_string(&directive.module_path), |
| module_to_string(self.current_module).unwrap_or_else(|| "???".to_string())); |
| |
| self.current_module = directive.parent_scope.module; |
| |
| let module = if let Some(module) = directive.imported_module.get() { |
| module |
| } else { |
| // For better failure detection, pretend that the import will |
| // not define any names while resolving its module path. |
| let orig_vis = directive.vis.replace(ty::Visibility::Invisible); |
| let path_res = self.resolve_path( |
| &directive.module_path, |
| None, |
| &directive.parent_scope, |
| false, |
| directive.span, |
| directive.crate_lint(), |
| ); |
| directive.vis.set(orig_vis); |
| |
| match path_res { |
| PathResult::Module(module) => module, |
| PathResult::Indeterminate => return false, |
| PathResult::NonModule(..) | PathResult::Failed(..) => return true, |
| } |
| }; |
| |
| directive.imported_module.set(Some(module)); |
| let (source, target, result, type_ns_only) = match directive.subclass { |
| SingleImport { source, target, ref result, type_ns_only } => |
| (source, target, result, type_ns_only), |
| GlobImport { .. } => { |
| self.resolve_glob_import(directive); |
| return true; |
| } |
| _ => unreachable!(), |
| }; |
| |
| let mut indeterminate = false; |
| self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS { |
| if let Err(Undetermined) = result[ns].get() { |
| // For better failure detection, pretend that the import will |
| // not define any names while resolving its module path. |
| let orig_vis = directive.vis.replace(ty::Visibility::Invisible); |
| let binding = this.resolve_ident_in_module( |
| module, source, ns, Some(&directive.parent_scope), false, directive.span |
| ); |
| directive.vis.set(orig_vis); |
| |
| result[ns].set(binding); |
| } else { |
| return |
| }; |
| |
| let parent = directive.parent_scope.module; |
| match result[ns].get() { |
| Err(Undetermined) => indeterminate = true, |
| Err(Determined) => { |
| this.update_resolution(parent, target, ns, |_, resolution| { |
| resolution.single_imports.remove(&PtrKey(directive)); |
| }); |
| } |
| Ok(binding) if !binding.is_importable() => { |
| let msg = format!("`{}` is not directly importable", target); |
| struct_span_err!(this.session, directive.span, E0253, "{}", &msg) |
| .span_label(directive.span, "cannot be imported directly") |
| .emit(); |
| // Do not import this illegal binding. Import a dummy binding and pretend |
| // everything is fine |
| this.import_dummy_binding(directive); |
| } |
| Ok(binding) => { |
| let imported_binding = this.import(binding, directive); |
| let conflict = this.try_define(parent, target, ns, imported_binding); |
| if let Err(old_binding) = conflict { |
| this.report_conflict(parent, target, ns, imported_binding, old_binding); |
| } |
| } |
| } |
| }); |
| |
| !indeterminate |
| } |
| |
| // If appropriate, returns an error to report. |
| fn finalize_import( |
| &mut self, |
| directive: &'b ImportDirective<'b> |
| ) -> Option<(Span, String, Option<String>)> { |
| self.current_module = directive.parent_scope.module; |
| |
| let orig_vis = directive.vis.replace(ty::Visibility::Invisible); |
| let path_res = self.resolve_path(&directive.module_path, None, &directive.parent_scope, |
| true, directive.span, directive.crate_lint()); |
| directive.vis.set(orig_vis); |
| let module = match path_res { |
| PathResult::Module(module) => { |
| // Consistency checks, analogous to `finalize_current_module_macro_resolutions`. |
| if let Some(initial_module) = directive.imported_module.get() { |
| if !ModuleOrUniformRoot::same_def(module, initial_module) |
| && self.ambiguity_errors.is_empty() |
| { |
| span_bug!(directive.span, "inconsistent resolution for an import"); |
| } |
| } else { |
| if self.privacy_errors.is_empty() { |
| let msg = "cannot determine resolution for the import"; |
| let msg_note = "import resolution is stuck, try simplifying other imports"; |
| self.session.struct_span_err(directive.span, msg).note(msg_note).emit(); |
| } |
| } |
| |
| module |
| } |
| PathResult::Failed(span, msg, false) => { |
| assert!(!self.ambiguity_errors.is_empty() || |
| directive.imported_module.get().is_none()); |
| resolve_error(self, span, ResolutionError::FailedToResolve(&msg)); |
| return None; |
| } |
| PathResult::Failed(span, msg, true) => { |
| assert!(!self.ambiguity_errors.is_empty() || |
| directive.imported_module.get().is_none()); |
| return if let Some((suggested_path, note)) = self.make_path_suggestion( |
| span, directive.module_path.clone(), &directive.parent_scope |
| ) { |
| Some(( |
| span, |
| format!("did you mean `{}`?", Segment::names_to_string(&suggested_path)), |
| note, |
| )) |
| } else { |
| Some((span, msg, None)) |
| }; |
| } |
| PathResult::NonModule(path_res) if path_res.base_def() == Def::Err => { |
| // The error was already reported earlier. |
| assert!(!self.ambiguity_errors.is_empty() || |
| directive.imported_module.get().is_none()); |
| return None; |
| } |
| PathResult::Indeterminate | PathResult::NonModule(..) => unreachable!(), |
| }; |
| |
| let (ident, result, type_ns_only) = match directive.subclass { |
| SingleImport { source, ref result, type_ns_only, .. } => (source, result, type_ns_only), |
| GlobImport { is_prelude, ref max_vis } => { |
| if directive.module_path.len() <= 1 { |
| // HACK(eddyb) `lint_if_path_starts_with_module` needs at least |
| // 2 segments, so the `resolve_path` above won't trigger it. |
| let mut full_path = directive.module_path.clone(); |
| full_path.push(Segment::from_ident(keywords::Invalid.ident())); |
| self.lint_if_path_starts_with_module( |
| directive.crate_lint(), |
| &full_path, |
| directive.span, |
| None, |
| ); |
| } |
| |
| if let ModuleOrUniformRoot::Module(module) = module { |
| if module.def_id() == directive.parent_scope.module.def_id() { |
| // Importing a module into itself is not allowed. |
| return Some(( |
| directive.span, |
| "Cannot glob-import a module into itself.".to_string(), |
| None, |
| )); |
| } |
| } |
| if !is_prelude && |
| max_vis.get() != ty::Visibility::Invisible && // Allow empty globs. |
| !max_vis.get().is_at_least(directive.vis.get(), &*self) { |
| let msg = "A non-empty glob must import something with the glob's visibility"; |
| self.session.span_err(directive.span, msg); |
| } |
| return None; |
| } |
| _ => unreachable!(), |
| }; |
| |
| let mut all_ns_err = true; |
| self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS { |
| let orig_vis = directive.vis.replace(ty::Visibility::Invisible); |
| let orig_last_import_segment = mem::replace(&mut this.last_import_segment, true); |
| let binding = this.resolve_ident_in_module( |
| module, ident, ns, Some(&directive.parent_scope), true, directive.span |
| ); |
| this.last_import_segment = orig_last_import_segment; |
| directive.vis.set(orig_vis); |
| |
| match binding { |
| Ok(binding) => { |
| // Consistency checks, analogous to `finalize_current_module_macro_resolutions`. |
| let initial_def = result[ns].get().map(|initial_binding| { |
| all_ns_err = false; |
| this.record_use(ident, ns, initial_binding, |
| directive.module_path.is_empty()); |
| initial_binding.def_ignoring_ambiguity() |
| }); |
| let def = binding.def_ignoring_ambiguity(); |
| if let Ok(initial_def) = initial_def { |
| if def != initial_def && this.ambiguity_errors.is_empty() { |
| span_bug!(directive.span, "inconsistent resolution for an import"); |
| } |
| } else { |
| if def != Def::Err && |
| this.ambiguity_errors.is_empty() && this.privacy_errors.is_empty() { |
| let msg = "cannot determine resolution for the import"; |
| let msg_note = |
| "import resolution is stuck, try simplifying other imports"; |
| this.session.struct_span_err(directive.span, msg).note(msg_note).emit(); |
| } |
| } |
| } |
| Err(..) => { |
| // FIXME: This assert may fire if public glob is later shadowed by a private |
| // single import (see test `issue-55884-2.rs`). In theory single imports should |
| // always block globs, even if they are not yet resolved, so that this kind of |
| // self-inconsistent resolution never happens. |
| // Reenable the assert when the issue is fixed. |
| // assert!(result[ns].get().is_err()); |
| } |
| } |
| }); |
| |
| if all_ns_err { |
| let mut all_ns_failed = true; |
| self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS { |
| let binding = this.resolve_ident_in_module( |
| module, ident, ns, Some(&directive.parent_scope), true, directive.span |
| ); |
| if binding.is_ok() { |
| all_ns_failed = false; |
| } |
| }); |
| |
| return if all_ns_failed { |
| let resolutions = match module { |
| ModuleOrUniformRoot::Module(module) => Some(module.resolutions.borrow()), |
| _ => None, |
| }; |
| let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter()); |
| let names = resolutions.filter_map(|(&(ref i, _), resolution)| { |
| if *i == ident { return None; } // Never suggest the same name |
| match *resolution.borrow() { |
| NameResolution { binding: Some(name_binding), .. } => { |
| match name_binding.kind { |
| NameBindingKind::Import { binding, .. } => { |
| match binding.kind { |
| // Never suggest the name that has binding error |
| // i.e. the name that cannot be previously resolved |
| NameBindingKind::Def(Def::Err, _) => return None, |
| _ => Some(&i.name), |
| } |
| }, |
| _ => Some(&i.name), |
| } |
| }, |
| NameResolution { ref single_imports, .. } |
| if single_imports.is_empty() => None, |
| _ => Some(&i.name), |
| } |
| }); |
| let lev_suggestion = |
| match find_best_match_for_name(names, &ident.as_str(), None) { |
| Some(name) => format!(". Did you mean to use `{}`?", name), |
| None => String::new(), |
| }; |
| let msg = match module { |
| ModuleOrUniformRoot::Module(module) => { |
| let module_str = module_to_string(module); |
| if let Some(module_str) = module_str { |
| format!("no `{}` in `{}`{}", ident, module_str, lev_suggestion) |
| } else { |
| format!("no `{}` in the root{}", ident, lev_suggestion) |
| } |
| } |
| _ => { |
| if !ident.is_path_segment_keyword() { |
| format!("no `{}` external crate{}", ident, lev_suggestion) |
| } else { |
| // HACK(eddyb) this shows up for `self` & `super`, which |
| // should work instead - for now keep the same error message. |
| format!("no `{}` in the root{}", ident, lev_suggestion) |
| } |
| } |
| }; |
| Some((directive.span, msg, None)) |
| } else { |
| // `resolve_ident_in_module` reported a privacy error. |
| self.import_dummy_binding(directive); |
| None |
| } |
| } |
| |
| let mut reexport_error = None; |
| let mut any_successful_reexport = false; |
| self.per_ns(|this, ns| { |
| if let Ok(binding) = result[ns].get() { |
| let vis = directive.vis.get(); |
| if !binding.pseudo_vis().is_at_least(vis, &*this) { |
| reexport_error = Some((ns, binding)); |
| } else { |
| any_successful_reexport = true; |
| } |
| } |
| }); |
| |
| // All namespaces must be re-exported with extra visibility for an error to occur. |
| if !any_successful_reexport { |
| let (ns, binding) = reexport_error.unwrap(); |
| if ns == TypeNS && binding.is_extern_crate() { |
| let msg = format!("extern crate `{}` is private, and cannot be \ |
| re-exported (error E0365), consider declaring with \ |
| `pub`", |
| ident); |
| self.session.buffer_lint(PUB_USE_OF_PRIVATE_EXTERN_CRATE, |
| directive.id, |
| directive.span, |
| &msg); |
| } else if ns == TypeNS { |
| struct_span_err!(self.session, directive.span, E0365, |
| "`{}` is private, and cannot be re-exported", ident) |
| .span_label(directive.span, format!("re-export of private `{}`", ident)) |
| .note(&format!("consider declaring type or module `{}` with `pub`", ident)) |
| .emit(); |
| } else { |
| let msg = format!("`{}` is private, and cannot be re-exported", ident); |
| let note_msg = |
| format!("consider marking `{}` as `pub` in the imported module", ident); |
| struct_span_err!(self.session, directive.span, E0364, "{}", &msg) |
| .span_note(directive.span, ¬e_msg) |
| .emit(); |
| } |
| } |
| |
| if directive.module_path.len() <= 1 { |
| // HACK(eddyb) `lint_if_path_starts_with_module` needs at least |
| // 2 segments, so the `resolve_path` above won't trigger it. |
| let mut full_path = directive.module_path.clone(); |
| full_path.push(Segment::from_ident(ident)); |
| self.per_ns(|this, ns| { |
| if let Ok(binding) = result[ns].get() { |
| this.lint_if_path_starts_with_module( |
| directive.crate_lint(), |
| &full_path, |
| directive.span, |
| Some(binding), |
| ); |
| } |
| }); |
| } |
| |
| // Record what this import resolves to for later uses in documentation, |
| // this may resolve to either a value or a type, but for documentation |
| // purposes it's good enough to just favor one over the other. |
| self.per_ns(|this, ns| if let Some(binding) = result[ns].get().ok() { |
| let mut def = binding.def(); |
| if let Def::Macro(def_id, _) = def { |
| // `DefId`s from the "built-in macro crate" should not leak from resolve because |
| // later stages are not ready to deal with them and produce lots of ICEs. Replace |
| // them with `Def::Err` until some saner scheme is implemented for built-in macros. |
| if def_id.krate == CrateNum::BuiltinMacros { |
| this.session.span_err(directive.span, "cannot import a built-in macro"); |
| def = Def::Err; |
| } |
| } |
| let import = this.import_map.entry(directive.id).or_default(); |
| import[ns] = Some(PathResolution::new(def)); |
| }); |
| |
| debug!("(resolving single import) successfully resolved import"); |
| None |
| } |
| |
| fn resolve_glob_import(&mut self, directive: &'b ImportDirective<'b>) { |
| let module = match directive.imported_module.get().unwrap() { |
| ModuleOrUniformRoot::Module(module) => module, |
| _ => { |
| self.session.span_err(directive.span, "cannot glob-import all possible crates"); |
| return; |
| } |
| }; |
| |
| self.populate_module_if_necessary(module); |
| |
| if let Some(Def::Trait(_)) = module.def() { |
| self.session.span_err(directive.span, "items in traits are not importable."); |
| return; |
| } else if module.def_id() == directive.parent_scope.module.def_id() { |
| return; |
| } else if let GlobImport { is_prelude: true, .. } = directive.subclass { |
| self.prelude = Some(module); |
| return; |
| } |
| |
| // Add to module's glob_importers |
| module.glob_importers.borrow_mut().push(directive); |
| |
| // Ensure that `resolutions` isn't borrowed during `try_define`, |
| // since it might get updated via a glob cycle. |
| let bindings = module.resolutions.borrow().iter().filter_map(|(&ident, resolution)| { |
| resolution.borrow().binding().map(|binding| (ident, binding)) |
| }).collect::<Vec<_>>(); |
| for ((mut ident, ns), binding) in bindings { |
| let scope = match ident.span.reverse_glob_adjust(module.expansion, |
| directive.span.ctxt().modern()) { |
| Some(Some(def)) => self.macro_def_scope(def), |
| Some(None) => self.current_module, |
| None => continue, |
| }; |
| if self.is_accessible_from(binding.pseudo_vis(), scope) { |
| let imported_binding = self.import(binding, directive); |
| let _ = self.try_define(directive.parent_scope.module, ident, ns, imported_binding); |
| } |
| } |
| |
| // Record the destination of this import |
| self.record_def(directive.id, PathResolution::new(module.def().unwrap())); |
| } |
| |
| // Miscellaneous post-processing, including recording re-exports, |
| // reporting conflicts, and reporting unresolved imports. |
| fn finalize_resolutions_in(&mut self, module: Module<'b>) { |
| // Since import resolution is finished, globs will not define any more names. |
| *module.globs.borrow_mut() = Vec::new(); |
| |
| let mut reexports = Vec::new(); |
| |
| for (&(ident, ns), resolution) in module.resolutions.borrow().iter() { |
| let resolution = &mut *resolution.borrow_mut(); |
| let binding = match resolution.binding { |
| Some(binding) => binding, |
| None => continue, |
| }; |
| |
| // Filter away "empty import canaries". |
| let is_non_canary_import = |
| binding.is_import() && binding.vis != ty::Visibility::Invisible; |
| if is_non_canary_import || binding.is_macro_def() { |
| let def = binding.def(); |
| if def != Def::Err { |
| if let Some(def_id) = def.opt_def_id() { |
| if !def_id.is_local() && def_id.krate != CrateNum::BuiltinMacros { |
| self.cstore.export_macros_untracked(def_id.krate); |
| } |
| } |
| reexports.push(Export { |
| ident: ident.modern(), |
| def: def, |
| span: binding.span, |
| vis: binding.vis, |
| }); |
| } |
| } |
| |
| if let NameBindingKind::Import { binding: orig_binding, directive, .. } = binding.kind { |
| if ns == TypeNS && orig_binding.is_variant() && |
| !orig_binding.vis.is_at_least(binding.vis, &*self) { |
| let msg = match directive.subclass { |
| ImportDirectiveSubclass::SingleImport { .. } => { |
| format!("variant `{}` is private and cannot be re-exported", |
| ident) |
| }, |
| ImportDirectiveSubclass::GlobImport { .. } => { |
| let msg = "enum is private and its variants \ |
| cannot be re-exported".to_owned(); |
| let error_id = (DiagnosticMessageId::ErrorId(0), // no code?! |
| Some(binding.span), |
| msg.clone()); |
| let fresh = self.session.one_time_diagnostics |
| .borrow_mut().insert(error_id); |
| if !fresh { |
| continue; |
| } |
| msg |
| }, |
| ref s @ _ => bug!("unexpected import subclass {:?}", s) |
| }; |
| let mut err = self.session.struct_span_err(binding.span, &msg); |
| |
| let imported_module = match directive.imported_module.get() { |
| Some(ModuleOrUniformRoot::Module(module)) => module, |
| _ => bug!("module should exist"), |
| }; |
| let resolutions = imported_module.parent.expect("parent should exist") |
| .resolutions.borrow(); |
| let enum_path_segment_index = directive.module_path.len() - 1; |
| let enum_ident = directive.module_path[enum_path_segment_index].ident; |
| |
| let enum_resolution = resolutions.get(&(enum_ident, TypeNS)) |
| .expect("resolution should exist"); |
| let enum_span = enum_resolution.borrow() |
| .binding.expect("binding should exist") |
| .span; |
| let enum_def_span = self.session.source_map().def_span(enum_span); |
| let enum_def_snippet = self.session.source_map() |
| .span_to_snippet(enum_def_span).expect("snippet should exist"); |
| // potentially need to strip extant `crate`/`pub(path)` for suggestion |
| let after_vis_index = enum_def_snippet.find("enum") |
| .expect("`enum` keyword should exist in snippet"); |
| let suggestion = format!("pub {}", |
| &enum_def_snippet[after_vis_index..]); |
| |
| self.session |
| .diag_span_suggestion_once(&mut err, |
| DiagnosticMessageId::ErrorId(0), |
| enum_def_span, |
| "consider making the enum public", |
| suggestion); |
| err.emit(); |
| } |
| } |
| } |
| |
| if reexports.len() > 0 { |
| if let Some(def_id) = module.def_id() { |
| self.export_map.insert(def_id, reexports); |
| } |
| } |
| } |
| } |
| |
| fn import_path_to_string(names: &[Ident], |
| subclass: &ImportDirectiveSubclass, |
| span: Span) -> String { |
| let pos = names.iter() |
| .position(|p| span == p.span && p.name != keywords::CrateRoot.name()); |
| let global = !names.is_empty() && names[0].name == keywords::CrateRoot.name(); |
| if let Some(pos) = pos { |
| let names = if global { &names[1..pos + 1] } else { &names[..pos + 1] }; |
| names_to_string(names) |
| } else { |
| let names = if global { &names[1..] } else { names }; |
| if names.is_empty() { |
| import_directive_subclass_to_string(subclass) |
| } else { |
| format!("{}::{}", |
| names_to_string(names), |
| import_directive_subclass_to_string(subclass)) |
| } |
| } |
| } |
| |
| fn import_directive_subclass_to_string(subclass: &ImportDirectiveSubclass) -> String { |
| match *subclass { |
| SingleImport { source, .. } => source.to_string(), |
| GlobImport { .. } => "*".to_string(), |
| ExternCrate { .. } => "<extern crate>".to_string(), |
| MacroUse => "#[macro_use]".to_string(), |
| } |
| } |
