| //! A bunch of methods and structures more or less related to resolving imports. |
| |
| use crate::diagnostics::{import_candidates, DiagnosticMode, Suggestion}; |
| use crate::Determinacy::{self, *}; |
| use crate::Namespace::*; |
| use crate::{module_to_string, names_to_string, ImportSuggestion}; |
| use crate::{ |
| AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BindingKey, ModuleKind, ResolutionError, |
| Resolver, Segment, |
| }; |
| use crate::{Finalize, Module, ModuleOrUniformRoot, ParentScope, PerNS, ScopeSet}; |
| use crate::{NameBinding, NameBindingKind, PathResult}; |
| |
| use rustc_ast::NodeId; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_data_structures::intern::Interned; |
| use rustc_errors::{pluralize, struct_span_err, Applicability, MultiSpan}; |
| use rustc_hir::def::{self, DefKind, PartialRes}; |
| use rustc_middle::metadata::ModChild; |
| use rustc_middle::metadata::Reexport; |
| use rustc_middle::span_bug; |
| use rustc_middle::ty; |
| use rustc_session::lint::builtin::{ |
| AMBIGUOUS_GLOB_REEXPORTS, PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS, |
| }; |
| use rustc_session::lint::BuiltinLintDiagnostics; |
| use rustc_span::edit_distance::find_best_match_for_name; |
| use rustc_span::hygiene::LocalExpnId; |
| use rustc_span::symbol::{kw, Ident, Symbol}; |
| use rustc_span::Span; |
| use smallvec::SmallVec; |
| |
| use std::cell::Cell; |
| use std::{mem, ptr}; |
| |
| type Res = def::Res<NodeId>; |
| |
| /// Contains data for specific kinds of imports. |
| #[derive(Clone)] |
| pub(crate) enum ImportKind<'a> { |
| Single { |
| /// `source` in `use prefix::source as target`. |
| source: Ident, |
| /// `target` in `use prefix::source as target`. |
| target: Ident, |
| /// Bindings to which `source` refers to. |
| source_bindings: PerNS<Cell<Result<&'a NameBinding<'a>, Determinacy>>>, |
| /// Bindings introduced by `target`. |
| target_bindings: PerNS<Cell<Option<&'a NameBinding<'a>>>>, |
| /// `true` for `...::{self [as target]}` imports, `false` otherwise. |
| type_ns_only: bool, |
| /// Did this import result from a nested import? ie. `use foo::{bar, baz};` |
| nested: bool, |
| /// The ID of the `UseTree` that imported this `Import`. |
| /// |
| /// In the case where the `Import` was expanded from a "nested" use tree, |
| /// this id is the ID of the leaf tree. For example: |
| /// |
| /// ```ignore (pacify the merciless tidy) |
| /// use foo::bar::{a, b} |
| /// ``` |
| /// |
| /// If this is the import for `foo::bar::a`, we would have the ID of the `UseTree` |
| /// for `a` in this field. |
| id: NodeId, |
| }, |
| Glob { |
| is_prelude: bool, |
| // The visibility of the greatest re-export. |
| // n.b. `max_vis` is only used in `finalize_import` to check for re-export errors. |
| max_vis: Cell<Option<ty::Visibility>>, |
| id: NodeId, |
| }, |
| ExternCrate { |
| source: Option<Symbol>, |
| target: Ident, |
| id: NodeId, |
| }, |
| MacroUse, |
| MacroExport, |
| } |
| |
| /// Manually implement `Debug` for `ImportKind` because the `source/target_bindings` |
| /// contain `Cell`s which can introduce infinite loops while printing. |
| impl<'a> std::fmt::Debug for ImportKind<'a> { |
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| use ImportKind::*; |
| match self { |
| Single { |
| ref source, |
| ref target, |
| ref source_bindings, |
| ref target_bindings, |
| ref type_ns_only, |
| ref nested, |
| ref id, |
| } => f |
| .debug_struct("Single") |
| .field("source", source) |
| .field("target", target) |
| // Ignore the nested bindings to avoid an infinite loop while printing. |
| .field( |
| "source_bindings", |
| &source_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))), |
| ) |
| .field( |
| "target_bindings", |
| &target_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))), |
| ) |
| .field("type_ns_only", type_ns_only) |
| .field("nested", nested) |
| .field("id", id) |
| .finish(), |
| Glob { ref is_prelude, ref max_vis, ref id } => f |
| .debug_struct("Glob") |
| .field("is_prelude", is_prelude) |
| .field("max_vis", max_vis) |
| .field("id", id) |
| .finish(), |
| ExternCrate { ref source, ref target, ref id } => f |
| .debug_struct("ExternCrate") |
| .field("source", source) |
| .field("target", target) |
| .field("id", id) |
| .finish(), |
| MacroUse => f.debug_struct("MacroUse").finish(), |
| MacroExport => f.debug_struct("MacroExport").finish(), |
| } |
| } |
| } |
| |
| /// One import. |
| #[derive(Debug, Clone)] |
| pub(crate) struct Import<'a> { |
| pub kind: ImportKind<'a>, |
| |
| /// Node ID of the "root" use item -- this is always the same as `ImportKind`'s `id` |
| /// (if it exists) 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 |
| /// ```ignore (incomplete code) |
| /// use foo::bar::{a, b} |
| /// ``` |
| /// this would be the ID of the `use foo::bar` `UseTree` node. |
| /// In case of imports without their own node ID it's the closest node that can be used, |
| /// for example, for reporting lints. |
| pub root_id: NodeId, |
| |
| /// Span of the entire use statement. |
| pub use_span: Span, |
| |
| /// Span of the entire use statement with attributes. |
| pub use_span_with_attributes: Span, |
| |
| /// Did the use statement have any attributes? |
| pub has_attributes: bool, |
| |
| /// 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 vis: Cell<Option<ty::Visibility>>, |
| pub used: Cell<bool>, |
| } |
| |
| impl<'a> Import<'a> { |
| pub(crate) fn is_glob(&self) -> bool { |
| matches!(self.kind, ImportKind::Glob { .. }) |
| } |
| |
| pub(crate) fn is_nested(&self) -> bool { |
| match self.kind { |
| ImportKind::Single { nested, .. } => nested, |
| _ => false, |
| } |
| } |
| |
| pub(crate) fn expect_vis(&self) -> ty::Visibility { |
| self.vis.get().expect("encountered cleared import visibility") |
| } |
| |
| pub(crate) fn id(&self) -> Option<NodeId> { |
| match self.kind { |
| ImportKind::Single { id, .. } |
| | ImportKind::Glob { id, .. } |
| | ImportKind::ExternCrate { id, .. } => Some(id), |
| ImportKind::MacroUse | ImportKind::MacroExport => None, |
| } |
| } |
| |
| fn simplify(&self, r: &Resolver<'_, '_>) -> Reexport { |
| let to_def_id = |id| r.local_def_id(id).to_def_id(); |
| match self.kind { |
| ImportKind::Single { id, .. } => Reexport::Single(to_def_id(id)), |
| ImportKind::Glob { id, .. } => Reexport::Glob(to_def_id(id)), |
| ImportKind::ExternCrate { id, .. } => Reexport::ExternCrate(to_def_id(id)), |
| ImportKind::MacroUse => Reexport::MacroUse, |
| ImportKind::MacroExport => Reexport::MacroExport, |
| } |
| } |
| } |
| |
| /// Records information about the resolution of a name in a namespace of a module. |
| #[derive(Clone, Default, Debug)] |
| pub(crate) struct NameResolution<'a> { |
| /// Single imports that may define the name in the namespace. |
| /// Imports are arena-allocated, so it's ok to use pointers as keys. |
| pub single_imports: FxHashSet<Interned<'a, Import<'a>>>, |
| /// The least shadowable known binding for this name, or None if there are no known bindings. |
| pub binding: Option<&'a NameBinding<'a>>, |
| pub 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. |
| pub(crate) 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 |
| } |
| }) |
| } |
| |
| pub(crate) fn add_single_import(&mut self, import: &'a Import<'a>) { |
| self.single_imports.insert(Interned::new_unchecked(import)); |
| } |
| } |
| |
| /// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved |
| /// import errors within the same use tree into a single diagnostic. |
| #[derive(Debug, Clone)] |
| struct UnresolvedImportError { |
| span: Span, |
| label: Option<String>, |
| note: Option<String>, |
| suggestion: Option<Suggestion>, |
| candidates: Option<Vec<ImportSuggestion>>, |
| } |
| |
| // Reexports of the form `pub use foo as bar;` where `foo` is `extern crate foo;` |
| // are permitted for backward-compatibility under a deprecation lint. |
| fn pub_use_of_private_extern_crate_hack(import: &Import<'_>, binding: &NameBinding<'_>) -> bool { |
| match (&import.kind, &binding.kind) { |
| ( |
| ImportKind::Single { .. }, |
| NameBindingKind::Import { |
| import: Import { kind: ImportKind::ExternCrate { .. }, .. }, |
| .. |
| }, |
| ) => import.expect_vis().is_public(), |
| _ => false, |
| } |
| } |
| |
| impl<'a, 'tcx> Resolver<'a, 'tcx> { |
| /// Given a binding and an import that resolves to it, |
| /// return the corresponding binding defined by the import. |
| pub(crate) fn import( |
| &self, |
| binding: &'a NameBinding<'a>, |
| import: &'a Import<'a>, |
| ) -> &'a NameBinding<'a> { |
| let import_vis = import.expect_vis().to_def_id(); |
| let vis = if binding.vis.is_at_least(import_vis, self.tcx) |
| || pub_use_of_private_extern_crate_hack(import, binding) |
| { |
| import_vis |
| } else { |
| binding.vis |
| }; |
| |
| if let ImportKind::Glob { ref max_vis, .. } = import.kind { |
| if vis == import_vis |
| || max_vis.get().map_or(true, |max_vis| vis.is_at_least(max_vis, self.tcx)) |
| { |
| max_vis.set(Some(vis.expect_local())) |
| } |
| } |
| |
| self.arenas.alloc_name_binding(NameBinding { |
| kind: NameBindingKind::Import { binding, import, used: Cell::new(false) }, |
| ambiguity: None, |
| span: import.span, |
| vis, |
| expansion: import.parent_scope.expansion, |
| }) |
| } |
| |
| /// Define the name or return the existing binding if there is a collision. |
| pub(crate) fn try_define( |
| &mut self, |
| module: Module<'a>, |
| key: BindingKey, |
| binding: &'a NameBinding<'a>, |
| ) -> Result<(), &'a NameBinding<'a>> { |
| let res = binding.res(); |
| self.check_reserved_macro_name(key.ident, res); |
| self.set_binding_parent_module(binding, module); |
| self.update_resolution(module, key, |this, resolution| { |
| if let Some(old_binding) = resolution.binding { |
| if res == Res::Err && old_binding.res() != Res::Err { |
| // Do not override real bindings with `Res::Err`s from error recovery. |
| return Ok(()); |
| } |
| match (old_binding.is_glob_import(), binding.is_glob_import()) { |
| (true, true) => { |
| if res != old_binding.res() { |
| resolution.binding = Some(this.ambiguity( |
| AmbiguityKind::GlobVsGlob, |
| old_binding, |
| binding, |
| )); |
| } else if !old_binding.vis.is_at_least(binding.vis, this.tcx) { |
| // 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.res() != nonglob_binding.res() |
| && key.ns == MacroNS |
| && nonglob_binding.expansion != LocalExpnId::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) => { |
| return Err(old_binding); |
| } |
| } |
| } else { |
| resolution.binding = Some(binding); |
| } |
| |
| Ok(()) |
| }) |
| } |
| |
| fn ambiguity( |
| &self, |
| kind: AmbiguityKind, |
| primary_binding: &'a NameBinding<'a>, |
| secondary_binding: &'a NameBinding<'a>, |
| ) -> &'a NameBinding<'a> { |
| self.arenas.alloc_name_binding(NameBinding { |
| ambiguity: Some((secondary_binding, kind)), |
| ..primary_binding.clone() |
| }) |
| } |
| |
| // 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>, key: BindingKey, f: F) -> T |
| where |
| F: FnOnce(&mut Resolver<'a, 'tcx>, &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, key).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 import in module.glob_importers.borrow_mut().iter() { |
| let mut ident = key.ident; |
| let scope = match ident.span.reverse_glob_adjust(module.expansion, import.span) { |
| Some(Some(def)) => self.expn_def_scope(def), |
| Some(None) => import.parent_scope.module, |
| None => continue, |
| }; |
| if self.is_accessible_from(binding.vis, scope) { |
| let imported_binding = self.import(binding, import); |
| let key = BindingKey { ident, ..key }; |
| let _ = self.try_define(import.parent_scope.module, key, imported_binding); |
| } |
| } |
| |
| t |
| } |
| |
| // Define a dummy resolution containing a `Res::Err` as a placeholder for a failed |
| // or indeterminate resolution, also mark such failed imports as used to avoid duplicate diagnostics. |
| fn import_dummy_binding(&mut self, import: &'a Import<'a>, is_indeterminate: bool) { |
| if let ImportKind::Single { target, ref target_bindings, .. } = import.kind { |
| if !(is_indeterminate || target_bindings.iter().all(|binding| binding.get().is_none())) |
| { |
| return; // Has resolution, do not create the dummy binding |
| } |
| let dummy_binding = self.dummy_binding; |
| let dummy_binding = self.import(dummy_binding, import); |
| self.per_ns(|this, ns| { |
| let key = BindingKey::new(target, ns); |
| let _ = this.try_define(import.parent_scope.module, key, dummy_binding); |
| }); |
| self.record_use(target, dummy_binding, false); |
| } else if import.imported_module.get().is_none() { |
| import.used.set(true); |
| if let Some(id) = import.id() { |
| self.used_imports.insert(id); |
| } |
| } |
| } |
| |
| // 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(crate) fn resolve_imports(&mut self) { |
| let mut prev_indeterminate_count = usize::MAX; |
| let mut indeterminate_count = self.indeterminate_imports.len() * 3; |
| while indeterminate_count < prev_indeterminate_count { |
| prev_indeterminate_count = indeterminate_count; |
| indeterminate_count = 0; |
| for import in mem::take(&mut self.indeterminate_imports) { |
| let import_indeterminate_count = self.resolve_import(&import); |
| indeterminate_count += import_indeterminate_count; |
| match import_indeterminate_count { |
| 0 => self.determined_imports.push(import), |
| _ => self.indeterminate_imports.push(import), |
| } |
| } |
| } |
| } |
| |
| pub(crate) fn finalize_imports(&mut self) { |
| for module in self.arenas.local_modules().iter() { |
| self.finalize_resolutions_in(module); |
| } |
| |
| let mut seen_spans = FxHashSet::default(); |
| let mut errors = vec![]; |
| let mut prev_root_id: NodeId = NodeId::from_u32(0); |
| let determined_imports = mem::take(&mut self.determined_imports); |
| let indeterminate_imports = mem::take(&mut self.indeterminate_imports); |
| |
| for (is_indeterminate, import) in determined_imports |
| .into_iter() |
| .map(|i| (false, i)) |
| .chain(indeterminate_imports.into_iter().map(|i| (true, i))) |
| { |
| let unresolved_import_error = self.finalize_import(import); |
| |
| // If this import is unresolved then create a dummy import |
| // resolution for it so that later resolve stages won't complain. |
| self.import_dummy_binding(import, is_indeterminate); |
| |
| if let Some(err) = unresolved_import_error { |
| if let ImportKind::Single { source, ref source_bindings, .. } = import.kind { |
| if source.name == kw::SelfLower { |
| // Silence `unresolved import` error if E0429 is already emitted |
| if let Err(Determined) = source_bindings.value_ns.get() { |
| continue; |
| } |
| } |
| } |
| |
| if prev_root_id.as_u32() != 0 |
| && prev_root_id.as_u32() != import.root_id.as_u32() |
| && !errors.is_empty() |
| { |
| // In the case of a new import line, throw a diagnostic message |
| // for the previous line. |
| self.throw_unresolved_import_error(errors); |
| errors = vec![]; |
| } |
| if seen_spans.insert(err.span) { |
| errors.push((import, err)); |
| prev_root_id = import.root_id; |
| } |
| } else if is_indeterminate { |
| let path = import_path_to_string( |
| &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(), |
| &import.kind, |
| import.span, |
| ); |
| let err = UnresolvedImportError { |
| span: import.span, |
| label: None, |
| note: None, |
| suggestion: None, |
| candidates: None, |
| }; |
| // FIXME: there should be a better way of doing this than |
| // formatting this as a string then checking for `::` |
| if path.contains("::") { |
| errors.push((import, err)) |
| } |
| } |
| } |
| |
| if !errors.is_empty() { |
| self.throw_unresolved_import_error(errors); |
| } |
| } |
| |
| pub(crate) fn check_reexport_ambiguities( |
| &mut self, |
| exported_ambiguities: FxHashSet<Interned<'a, NameBinding<'a>>>, |
| ) { |
| for module in self.arenas.local_modules().iter() { |
| module.for_each_child(self, |this, ident, ns, binding| { |
| if let NameBindingKind::Import { import, .. } = binding.kind |
| && let Some((amb_binding, _)) = binding.ambiguity |
| && binding.res() != Res::Err |
| && exported_ambiguities.contains(&Interned::new_unchecked(binding)) |
| { |
| this.lint_buffer.buffer_lint_with_diagnostic( |
| AMBIGUOUS_GLOB_REEXPORTS, |
| import.root_id, |
| import.root_span, |
| "ambiguous glob re-exports", |
| BuiltinLintDiagnostics::AmbiguousGlobReexports { |
| name: ident.to_string(), |
| namespace: ns.descr().to_string(), |
| first_reexport_span: import.root_span, |
| duplicate_reexport_span: amb_binding.span, |
| }, |
| ); |
| } |
| }); |
| } |
| } |
| |
| fn throw_unresolved_import_error(&self, errors: Vec<(&Import<'_>, UnresolvedImportError)>) { |
| if errors.is_empty() { |
| return; |
| } |
| |
| /// Upper limit on the number of `span_label` messages. |
| const MAX_LABEL_COUNT: usize = 10; |
| |
| let span = MultiSpan::from_spans(errors.iter().map(|(_, err)| err.span).collect()); |
| let paths = errors |
| .iter() |
| .map(|(import, err)| { |
| let path = import_path_to_string( |
| &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(), |
| &import.kind, |
| err.span, |
| ); |
| format!("`{path}`") |
| }) |
| .collect::<Vec<_>>(); |
| let msg = format!("unresolved import{} {}", pluralize!(paths.len()), paths.join(", "),); |
| |
| let mut diag = struct_span_err!(self.tcx.sess, span, E0432, "{}", &msg); |
| |
| if let Some((_, UnresolvedImportError { note: Some(note), .. })) = errors.iter().last() { |
| diag.note(note.clone()); |
| } |
| |
| for (import, err) in errors.into_iter().take(MAX_LABEL_COUNT) { |
| if let Some(label) = err.label { |
| diag.span_label(err.span, label); |
| } |
| |
| if let Some((suggestions, msg, applicability)) = err.suggestion { |
| if suggestions.is_empty() { |
| diag.help(msg); |
| continue; |
| } |
| diag.multipart_suggestion(msg, suggestions, applicability); |
| } |
| |
| if let Some(candidates) = &err.candidates { |
| match &import.kind { |
| ImportKind::Single { nested: false, source, target, .. } => import_candidates( |
| self.tcx, |
| &mut diag, |
| Some(err.span), |
| &candidates, |
| DiagnosticMode::Import, |
| (source != target) |
| .then(|| format!(" as {target}")) |
| .as_deref() |
| .unwrap_or(""), |
| ), |
| ImportKind::Single { nested: true, source, target, .. } => { |
| import_candidates( |
| self.tcx, |
| &mut diag, |
| None, |
| &candidates, |
| DiagnosticMode::Normal, |
| (source != target) |
| .then(|| format!(" as {target}")) |
| .as_deref() |
| .unwrap_or(""), |
| ); |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| diag.emit(); |
| } |
| |
| /// Attempts to resolve the given import, returning: |
| /// - `0` means its resolution is determined. |
| /// - Other values mean that indeterminate exists under certain namespaces. |
| /// |
| /// Meanwhile, if resolve successful, the resolved bindings are written |
| /// into the module. |
| fn resolve_import(&mut self, import: &'a Import<'a>) -> usize { |
| debug!( |
| "(resolving import for module) resolving import `{}::...` in `{}`", |
| Segment::names_to_string(&import.module_path), |
| module_to_string(import.parent_scope.module).unwrap_or_else(|| "???".to_string()), |
| ); |
| |
| let module = if let Some(module) = import.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 = import.vis.take(); |
| let path_res = self.maybe_resolve_path(&import.module_path, None, &import.parent_scope); |
| import.vis.set(orig_vis); |
| |
| match path_res { |
| PathResult::Module(module) => module, |
| PathResult::Indeterminate => return 3, |
| PathResult::NonModule(..) | PathResult::Failed { .. } => return 0, |
| } |
| }; |
| |
| import.imported_module.set(Some(module)); |
| let (source, target, source_bindings, target_bindings, type_ns_only) = match import.kind { |
| ImportKind::Single { |
| source, |
| target, |
| ref source_bindings, |
| ref target_bindings, |
| type_ns_only, |
| .. |
| } => (source, target, source_bindings, target_bindings, type_ns_only), |
| ImportKind::Glob { .. } => { |
| self.resolve_glob_import(import); |
| return 0; |
| } |
| _ => unreachable!(), |
| }; |
| |
| let mut indeterminate_count = 0; |
| self.per_ns(|this, ns| { |
| if !type_ns_only || ns == TypeNS { |
| if let Err(Undetermined) = source_bindings[ns].get() { |
| // For better failure detection, pretend that the import will |
| // not define any names while resolving its module path. |
| let orig_vis = import.vis.take(); |
| let binding = this.resolve_ident_in_module( |
| module, |
| source, |
| ns, |
| &import.parent_scope, |
| None, |
| None, |
| ); |
| import.vis.set(orig_vis); |
| source_bindings[ns].set(binding); |
| } else { |
| return; |
| }; |
| |
| let parent = import.parent_scope.module; |
| match source_bindings[ns].get() { |
| Err(Undetermined) => indeterminate_count += 1, |
| // Don't update the resolution, because it was never added. |
| Err(Determined) if target.name == kw::Underscore => {} |
| Ok(binding) if binding.is_importable() => { |
| let imported_binding = this.import(binding, import); |
| target_bindings[ns].set(Some(imported_binding)); |
| this.define(parent, target, ns, imported_binding); |
| } |
| source_binding @ (Ok(..) | Err(Determined)) => { |
| if source_binding.is_ok() { |
| let msg = format!("`{}` is not directly importable", target); |
| struct_span_err!(this.tcx.sess, import.span, E0253, "{}", &msg) |
| .span_label(import.span, "cannot be imported directly") |
| .emit(); |
| } |
| let key = BindingKey::new(target, ns); |
| this.update_resolution(parent, key, |_, resolution| { |
| resolution.single_imports.remove(&Interned::new_unchecked(import)); |
| }); |
| } |
| } |
| } |
| }); |
| |
| indeterminate_count |
| } |
| |
| /// Performs final import resolution, consistency checks and error reporting. |
| /// |
| /// Optionally returns an unresolved import error. This error is buffered and used to |
| /// consolidate multiple unresolved import errors into a single diagnostic. |
| fn finalize_import(&mut self, import: &'a Import<'a>) -> Option<UnresolvedImportError> { |
| let orig_vis = import.vis.take(); |
| let ignore_binding = match &import.kind { |
| ImportKind::Single { target_bindings, .. } => target_bindings[TypeNS].get(), |
| _ => None, |
| }; |
| let prev_ambiguity_errors_len = self.ambiguity_errors.len(); |
| let finalize = Finalize::with_root_span(import.root_id, import.span, import.root_span); |
| let path_res = self.resolve_path( |
| &import.module_path, |
| None, |
| &import.parent_scope, |
| Some(finalize), |
| ignore_binding, |
| ); |
| |
| let no_ambiguity = self.ambiguity_errors.len() == prev_ambiguity_errors_len; |
| import.vis.set(orig_vis); |
| let module = match path_res { |
| PathResult::Module(module) => { |
| // Consistency checks, analogous to `finalize_macro_resolutions`. |
| if let Some(initial_module) = import.imported_module.get() { |
| if !ModuleOrUniformRoot::same_def(module, initial_module) && no_ambiguity { |
| span_bug!(import.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.tcx.sess.struct_span_err(import.span, msg).note(msg_note).emit(); |
| } |
| |
| module |
| } |
| PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => { |
| if no_ambiguity { |
| assert!(import.imported_module.get().is_none()); |
| self.report_error(span, ResolutionError::FailedToResolve { label, suggestion }); |
| } |
| return None; |
| } |
| PathResult::Failed { is_error_from_last_segment: true, span, label, suggestion } => { |
| if no_ambiguity { |
| assert!(import.imported_module.get().is_none()); |
| let err = match self.make_path_suggestion( |
| span, |
| import.module_path.clone(), |
| &import.parent_scope, |
| ) { |
| Some((suggestion, note)) => UnresolvedImportError { |
| span, |
| label: None, |
| note, |
| suggestion: Some(( |
| vec![(span, Segment::names_to_string(&suggestion))], |
| String::from("a similar path exists"), |
| Applicability::MaybeIncorrect, |
| )), |
| candidates: None, |
| }, |
| None => UnresolvedImportError { |
| span, |
| label: Some(label), |
| note: None, |
| suggestion, |
| candidates: None, |
| }, |
| }; |
| return Some(err); |
| } |
| return None; |
| } |
| PathResult::NonModule(_) => { |
| if no_ambiguity { |
| assert!(import.imported_module.get().is_none()); |
| } |
| // The error was already reported earlier. |
| return None; |
| } |
| PathResult::Indeterminate => unreachable!(), |
| }; |
| |
| let (ident, target, source_bindings, target_bindings, type_ns_only, import_id) = |
| match import.kind { |
| ImportKind::Single { |
| source, |
| target, |
| ref source_bindings, |
| ref target_bindings, |
| type_ns_only, |
| id, |
| .. |
| } => (source, target, source_bindings, target_bindings, type_ns_only, id), |
| ImportKind::Glob { is_prelude, ref max_vis, id } => { |
| if import.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 = import.module_path.clone(); |
| full_path.push(Segment::from_ident(Ident::empty())); |
| self.lint_if_path_starts_with_module(Some(finalize), &full_path, None); |
| } |
| |
| if let ModuleOrUniformRoot::Module(module) = module { |
| if ptr::eq(module, import.parent_scope.module) { |
| // Importing a module into itself is not allowed. |
| return Some(UnresolvedImportError { |
| span: import.span, |
| label: Some(String::from( |
| "cannot glob-import a module into itself", |
| )), |
| note: None, |
| suggestion: None, |
| candidates: None, |
| }); |
| } |
| } |
| if !is_prelude |
| && let Some(max_vis) = max_vis.get() |
| && !max_vis.is_at_least(import.expect_vis(), self.tcx) |
| { |
| let msg = "glob import doesn't reexport anything because no candidate is public enough"; |
| self.lint_buffer.buffer_lint(UNUSED_IMPORTS, id, import.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 = import.vis.take(); |
| let binding = this.resolve_ident_in_module( |
| module, |
| ident, |
| ns, |
| &import.parent_scope, |
| Some(Finalize { report_private: false, ..finalize }), |
| target_bindings[ns].get(), |
| ); |
| import.vis.set(orig_vis); |
| |
| match binding { |
| Ok(binding) => { |
| // Consistency checks, analogous to `finalize_macro_resolutions`. |
| let initial_binding = source_bindings[ns].get().map(|initial_binding| { |
| all_ns_err = false; |
| if let Some(target_binding) = target_bindings[ns].get() { |
| if target.name == kw::Underscore |
| && initial_binding.is_extern_crate() |
| && !initial_binding.is_import() |
| { |
| this.record_use( |
| ident, |
| target_binding, |
| import.module_path.is_empty(), |
| ); |
| } |
| } |
| initial_binding |
| }); |
| let res = binding.res(); |
| if let Ok(initial_binding) = initial_binding { |
| let initial_res = initial_binding.res(); |
| if res != initial_res && this.ambiguity_errors.is_empty() { |
| this.ambiguity_errors.push(AmbiguityError { |
| kind: AmbiguityKind::Import, |
| ident, |
| b1: initial_binding, |
| b2: binding, |
| misc1: AmbiguityErrorMisc::None, |
| misc2: AmbiguityErrorMisc::None, |
| }); |
| } |
| } else if res != Res::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.tcx.sess.struct_span_err(import.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. |
| // Re-enable 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, |
| &import.parent_scope, |
| Some(finalize), |
| None, |
| ); |
| if binding.is_ok() { |
| all_ns_failed = false; |
| } |
| } |
| }); |
| |
| return if all_ns_failed { |
| let resolutions = match module { |
| ModuleOrUniformRoot::Module(module) => Some(self.resolutions(module).borrow()), |
| _ => None, |
| }; |
| let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter()); |
| let names = resolutions |
| .filter_map(|(BindingKey { ident: i, .. }, resolution)| { |
| if i.name == ident.name { |
| 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::Res(Res::Err) => None, |
| _ => Some(i.name), |
| } |
| } |
| _ => Some(i.name), |
| } |
| } |
| NameResolution { ref single_imports, .. } |
| if single_imports.is_empty() => |
| { |
| None |
| } |
| _ => Some(i.name), |
| } |
| }) |
| .collect::<Vec<Symbol>>(); |
| |
| let lev_suggestion = |
| find_best_match_for_name(&names, ident.name, None).map(|suggestion| { |
| ( |
| vec![(ident.span, suggestion.to_string())], |
| String::from("a similar name exists in the module"), |
| Applicability::MaybeIncorrect, |
| ) |
| }); |
| |
| let (suggestion, note) = |
| match self.check_for_module_export_macro(import, module, ident) { |
| Some((suggestion, note)) => (suggestion.or(lev_suggestion), note), |
| _ => (lev_suggestion, None), |
| }; |
| |
| let label = 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) |
| } else { |
| format!("no `{}` in the root", ident) |
| } |
| } |
| _ => { |
| if !ident.is_path_segment_keyword() { |
| format!("no external crate `{}`", ident) |
| } 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) |
| } |
| } |
| }; |
| |
| let parent_suggestion = |
| self.lookup_import_candidates(ident, TypeNS, &import.parent_scope, |_| true); |
| |
| Some(UnresolvedImportError { |
| span: import.span, |
| label: Some(label), |
| note, |
| suggestion, |
| candidates: if !parent_suggestion.is_empty() { |
| Some(parent_suggestion) |
| } else { |
| None |
| }, |
| }) |
| } else { |
| // `resolve_ident_in_module` reported a privacy error. |
| None |
| }; |
| } |
| |
| let mut reexport_error = None; |
| let mut any_successful_reexport = false; |
| let mut crate_private_reexport = false; |
| self.per_ns(|this, ns| { |
| if let Ok(binding) = source_bindings[ns].get() { |
| if !binding.vis.is_at_least(import.expect_vis(), this.tcx) { |
| reexport_error = Some((ns, binding)); |
| if let ty::Visibility::Restricted(binding_def_id) = binding.vis { |
| if binding_def_id.is_top_level_module() { |
| crate_private_reexport = true; |
| } |
| } |
| } 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 pub_use_of_private_extern_crate_hack(import, binding) { |
| let msg = format!( |
| "extern crate `{}` is private, and cannot be \ |
| re-exported (error E0365), consider declaring with \ |
| `pub`", |
| ident |
| ); |
| self.lint_buffer.buffer_lint( |
| PUB_USE_OF_PRIVATE_EXTERN_CRATE, |
| import_id, |
| import.span, |
| msg, |
| ); |
| } else { |
| let error_msg = if crate_private_reexport { |
| format!( |
| "`{}` is only public within the crate, and cannot be re-exported outside", |
| ident |
| ) |
| } else { |
| format!("`{}` is private, and cannot be re-exported", ident) |
| }; |
| |
| if ns == TypeNS { |
| let label_msg = if crate_private_reexport { |
| format!("re-export of crate public `{}`", ident) |
| } else { |
| format!("re-export of private `{}`", ident) |
| }; |
| |
| struct_span_err!(self.tcx.sess, import.span, E0365, "{}", error_msg) |
| .span_label(import.span, label_msg) |
| .note(format!("consider declaring type or module `{}` with `pub`", ident)) |
| .emit(); |
| } else { |
| let mut err = |
| struct_span_err!(self.tcx.sess, import.span, E0364, "{error_msg}"); |
| match binding.kind { |
| NameBindingKind::Res(Res::Def(DefKind::Macro(_), def_id)) |
| // exclude decl_macro |
| if self.get_macro_by_def_id(def_id).macro_rules => |
| { |
| err.span_help( |
| binding.span, |
| "consider adding a `#[macro_export]` to the macro in the imported module", |
| ); |
| } |
| _ => { |
| err.span_note( |
| import.span, |
| format!( |
| "consider marking `{ident}` as `pub` in the imported module" |
| ), |
| ); |
| } |
| } |
| err.emit(); |
| } |
| } |
| } |
| |
| if import.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 = import.module_path.clone(); |
| full_path.push(Segment::from_ident(ident)); |
| self.per_ns(|this, ns| { |
| if let Ok(binding) = source_bindings[ns].get() { |
| this.lint_if_path_starts_with_module(Some(finalize), &full_path, 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 Ok(binding) = source_bindings[ns].get() { |
| this.import_res_map.entry(import_id).or_default()[ns] = Some(binding.res()); |
| } |
| }); |
| |
| self.check_for_redundant_imports(ident, import, source_bindings, target_bindings, target); |
| |
| debug!("(resolving single import) successfully resolved import"); |
| None |
| } |
| |
| fn check_for_redundant_imports( |
| &mut self, |
| ident: Ident, |
| import: &'a Import<'a>, |
| source_bindings: &PerNS<Cell<Result<&'a NameBinding<'a>, Determinacy>>>, |
| target_bindings: &PerNS<Cell<Option<&'a NameBinding<'a>>>>, |
| target: Ident, |
| ) { |
| // This function is only called for single imports. |
| let ImportKind::Single { id, .. } = import.kind else { unreachable!() }; |
| |
| // Skip if the import was produced by a macro. |
| if import.parent_scope.expansion != LocalExpnId::ROOT { |
| return; |
| } |
| |
| // Skip if we are inside a named module (in contrast to an anonymous |
| // module defined by a block). |
| if let ModuleKind::Def(..) = import.parent_scope.module.kind { |
| return; |
| } |
| |
| let mut is_redundant = PerNS { value_ns: None, type_ns: None, macro_ns: None }; |
| |
| let mut redundant_span = PerNS { value_ns: None, type_ns: None, macro_ns: None }; |
| |
| self.per_ns(|this, ns| { |
| if let Ok(binding) = source_bindings[ns].get() { |
| if binding.res() == Res::Err { |
| return; |
| } |
| |
| match this.early_resolve_ident_in_lexical_scope( |
| target, |
| ScopeSet::All(ns, false), |
| &import.parent_scope, |
| None, |
| false, |
| target_bindings[ns].get(), |
| ) { |
| Ok(other_binding) => { |
| is_redundant[ns] = Some( |
| binding.res() == other_binding.res() && !other_binding.is_ambiguity(), |
| ); |
| redundant_span[ns] = Some((other_binding.span, other_binding.is_import())); |
| } |
| Err(_) => is_redundant[ns] = Some(false), |
| } |
| } |
| }); |
| |
| if !is_redundant.is_empty() && is_redundant.present_items().all(|is_redundant| is_redundant) |
| { |
| let mut redundant_spans: Vec<_> = redundant_span.present_items().collect(); |
| redundant_spans.sort(); |
| redundant_spans.dedup(); |
| self.lint_buffer.buffer_lint_with_diagnostic( |
| UNUSED_IMPORTS, |
| id, |
| import.span, |
| format!("the item `{}` is imported redundantly", ident), |
| BuiltinLintDiagnostics::RedundantImport(redundant_spans, ident), |
| ); |
| } |
| } |
| |
| fn resolve_glob_import(&mut self, import: &'a Import<'a>) { |
| // This function is only called for glob imports. |
| let ImportKind::Glob { id, is_prelude, .. } = import.kind else { unreachable!() }; |
| |
| let ModuleOrUniformRoot::Module(module) = import.imported_module.get().unwrap() else { |
| self.tcx.sess.span_err(import.span, "cannot glob-import all possible crates"); |
| return; |
| }; |
| |
| if module.is_trait() { |
| self.tcx.sess.span_err(import.span, "items in traits are not importable"); |
| return; |
| } else if ptr::eq(module, import.parent_scope.module) { |
| return; |
| } else if is_prelude { |
| self.prelude = Some(module); |
| return; |
| } |
| |
| // Add to module's glob_importers |
| module.glob_importers.borrow_mut().push(import); |
| |
| // Ensure that `resolutions` isn't borrowed during `try_define`, |
| // since it might get updated via a glob cycle. |
| let bindings = self |
| .resolutions(module) |
| .borrow() |
| .iter() |
| .filter_map(|(key, resolution)| { |
| resolution.borrow().binding().map(|binding| (*key, binding)) |
| }) |
| .collect::<Vec<_>>(); |
| for (mut key, binding) in bindings { |
| let scope = match key.ident.span.reverse_glob_adjust(module.expansion, import.span) { |
| Some(Some(def)) => self.expn_def_scope(def), |
| Some(None) => import.parent_scope.module, |
| None => continue, |
| }; |
| if self.is_accessible_from(binding.vis, scope) { |
| let imported_binding = self.import(binding, import); |
| let _ = self.try_define(import.parent_scope.module, key, imported_binding); |
| } |
| } |
| |
| // Record the destination of this import |
| self.record_partial_res(id, PartialRes::new(module.res().unwrap())); |
| } |
| |
| // Miscellaneous post-processing, including recording re-exports, |
| // reporting conflicts, and reporting unresolved imports. |
| fn finalize_resolutions_in(&mut self, module: Module<'a>) { |
| // Since import resolution is finished, globs will not define any more names. |
| *module.globs.borrow_mut() = Vec::new(); |
| |
| if let Some(def_id) = module.opt_def_id() { |
| let mut children = Vec::new(); |
| |
| module.for_each_child(self, |this, ident, _, binding| { |
| let res = binding.res().expect_non_local(); |
| if res != def::Res::Err && !binding.is_ambiguity() { |
| let mut reexport_chain = SmallVec::new(); |
| let mut next_binding = binding; |
| while let NameBindingKind::Import { binding, import, .. } = next_binding.kind { |
| reexport_chain.push(import.simplify(this)); |
| next_binding = binding; |
| } |
| |
| children.push(ModChild { ident, res, vis: binding.vis, reexport_chain }); |
| } |
| }); |
| |
| if !children.is_empty() { |
| // Should be fine because this code is only called for local modules. |
| self.module_children.insert(def_id.expect_local(), children); |
| } |
| } |
| } |
| } |
| |
| fn import_path_to_string(names: &[Ident], import_kind: &ImportKind<'_>, span: Span) -> String { |
| let pos = names.iter().position(|p| span == p.span && p.name != kw::PathRoot); |
| let global = !names.is_empty() && names[0].name == kw::PathRoot; |
| if let Some(pos) = pos { |
| let names = if global { &names[1..pos + 1] } else { &names[..pos + 1] }; |
| names_to_string(&names.iter().map(|ident| ident.name).collect::<Vec<_>>()) |
| } else { |
| let names = if global { &names[1..] } else { names }; |
| if names.is_empty() { |
| import_kind_to_string(import_kind) |
| } else { |
| format!( |
| "{}::{}", |
| names_to_string(&names.iter().map(|ident| ident.name).collect::<Vec<_>>()), |
| import_kind_to_string(import_kind), |
| ) |
| } |
| } |
| } |
| |
| fn import_kind_to_string(import_kind: &ImportKind<'_>) -> String { |
| match import_kind { |
| ImportKind::Single { source, .. } => source.to_string(), |
| ImportKind::Glob { .. } => "*".to_string(), |
| ImportKind::ExternCrate { .. } => "<extern crate>".to_string(), |
| ImportKind::MacroUse => "#[macro_use]".to_string(), |
| ImportKind::MacroExport => "#[macro_export]".to_string(), |
| } |
| } |
