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use ImportDirectiveSubclass::*;
use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
use crate::{CrateLint, Module, ModuleOrUniformRoot, PerNS, ScopeSet, ParentScope, Weak};
use crate::Determinacy::{self, *};
use crate::Namespace::{self, TypeNS, MacroNS};
use crate::{NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError};
use crate::{Resolver, Segment};
use crate::{names_to_string, module_to_string};
use crate::{resolve_error, ResolutionError};
use crate::ModuleKind;
use crate::diagnostics::Suggestion;
use errors::Applicability;
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,
UNUSED_IMPORTS,
};
use rustc::hir::def_id::{CrateNum, DefId};
use rustc::hir::def::{self, DefKind, PartialRes, Export};
use rustc::session::DiagnosticMessageId;
use rustc::util::nodemap::FxHashSet;
use rustc::{bug, span_bug};
use syntax::ast::{self, Ident, Name, NodeId, CRATE_NODE_ID};
use syntax::ext::hygiene::ExpnId;
use syntax::symbol::kw;
use syntax::util::lev_distance::find_best_match_for_name;
use syntax::{struct_span_err, unwrap_or};
use syntax_pos::{MultiSpan, Span};
use log::*;
use std::cell::{Cell, RefCell};
use std::{mem, ptr};
type Res = def::Res<NodeId>;
/// Contains data for specific types of import directives.
#[derive(Clone, Debug)]
pub enum ImportDirectiveSubclass<'a> {
SingleImport {
/// `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,
},
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 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 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 }
}
pub fn is_nested(&self) -> bool {
match self.subclass {
ImportDirectiveSubclass::SingleImport { nested, .. } => nested,
_ => 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.
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 }
})
}
}
impl<'a> Resolver<'a> {
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 == kw::Crate ||
ident.name == kw::DollarCrate {
let module = self.resolve_crate_root(ident);
let binding = (module, ty::Visibility::Public,
module.span, ExpnId::root())
.to_name_binding(self.arenas);
return Ok(binding);
} else if ident.name == kw::Super ||
ident.name == kw::SelfLower {
// 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 != ExpnId::root() {
if let NameBindingKind::Res(_, true) = binding.kind {
self.macro_expanded_macro_export_errors.insert((path_span, binding.span));
}
}
}
let check_usable = |this: &mut Self, binding: &'a NameBinding<'a>| {
if let Some(blacklisted_binding) = this.blacklisted_binding {
if ptr::eq(binding, blacklisted_binding) {
return Err((Determined, Weak::No));
}
}
// `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.and_then(|binding| {
// If the primary binding is blacklisted, search further and return the shadowed
// glob binding if it exists. What we really want here is having two separate
// scopes in a module - one for non-globs and one for globs, but until that's done
// use this hack to avoid inconsistent resolution ICEs during import validation.
if let Some(blacklisted_binding) = self.blacklisted_binding {
if ptr::eq(binding, blacklisted_binding) {
return resolution.shadowed_glob;
}
}
Some(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 != ExpnId::root() &&
binding.res() != shadowed_glob.res() {
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) {
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,
item: &ast::Item,
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,
use_span: item.span,
use_span_with_attributes: item.span_with_attributes(),
has_attributes: !item.attrs.is_empty(),
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) ||
// cf. `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),
},
ambiguity: None,
span: directive.span,
vis,
expansion: directive.parent_scope.expansion,
})
}
// 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>> {
let res = binding.res();
self.check_reserved_macro_name(ident, res);
self.set_binding_parent_module(binding, module);
self.update_resolution(module, ident, ns, |this, resolution| {
if let Some(old_binding) = resolution.binding {
if 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) {
// 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() &&
ns == MacroNS && nonglob_binding.expansion != ExpnId::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::Res(_, true), &NameBindingKind::Res(_, 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,
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>, ident: Ident, ns: Namespace, f: F)
-> T
where F: FnOnce(&mut Resolver<'a>, &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) {
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 Res::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);
// Consider erroneous imports used to avoid duplicate diagnostics.
this.record_use(target, ns, dummy_binding, false);
});
}
}
}
/// 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: Vec<String>,
suggestion: Option<Suggestion>,
}
pub struct ImportResolver<'a, 'b> {
pub resolver: &'a mut Resolver<'b>,
}
impl<'a, 'b> std::ops::Deref for ImportResolver<'a, 'b> {
type Target = Resolver<'b>;
fn deref(&self) -> &Resolver<'b> {
self.resolver
}
}
impl<'a, 'b> std::ops::DerefMut for ImportResolver<'a, 'b> {
fn deref_mut(&mut self) -> &mut Resolver<'b> {
self.resolver
}
}
impl<'a, 'b> ty::DefIdTree for &'a ImportResolver<'a, 'b> {
fn parent(self, id: DefId) -> Option<DefId> {
self.resolver.parent(id)
}
}
impl<'a, 'b> ImportResolver<'a, 'b> {
// 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::take(&mut self.indeterminate_imports) {
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 has_errors = false;
let mut seen_spans = FxHashSet::default();
let mut errors = vec![];
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(err) = self.finalize_import(import) {
has_errors = true;
if let SingleImport { source, ref source_bindings, .. } = import.subclass {
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 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()
&& !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, None);
errors = vec![];
}
if !seen_spans.contains(&err.span) {
let path = import_path_to_string(
&import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
&import.subclass,
err.span,
);
seen_spans.insert(err.span);
errors.push((path, err));
prev_root_id = import.root_id;
}
}
}
if !errors.is_empty() {
self.throw_unresolved_import_error(errors.clone(), None);
}
// Report unresolved imports only if no hard error was already reported
// to avoid generating multiple errors on the same import.
if !has_errors {
for import in &self.indeterminate_imports {
self.throw_unresolved_import_error(errors, Some(MultiSpan::from(import.span)));
break;
}
}
}
fn throw_unresolved_import_error(
&self,
errors: Vec<(String, UnresolvedImportError)>,
span: Option<MultiSpan>,
) {
/// Upper limit on the number of `span_label` messages.
const MAX_LABEL_COUNT: usize = 10;
let (span, msg) = if errors.is_empty() {
(span.unwrap(), "unresolved import".to_string())
} else {
let span = MultiSpan::from_spans(
errors
.iter()
.map(|(_, err)| err.span)
.collect(),
);
let paths = errors
.iter()
.map(|(path, _)| format!("`{}`", path))
.collect::<Vec<_>>();
let msg = format!(
"unresolved import{} {}",
if paths.len() > 1 { "s" } else { "" },
paths.join(", "),
);
(span, msg)
};
let mut diag = struct_span_err!(self.resolver.session, span, E0432, "{}", &msg);
if let Some((_, UnresolvedImportError { note, .. })) = errors.iter().last() {
for message in note {
diag.note(&message);
}
}
for (_, 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 {
diag.multipart_suggestion(&msg, suggestions, applicability);
}
}
diag.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, source_bindings, target_bindings, type_ns_only) =
match directive.subclass {
SingleImport { source, target, ref source_bindings,
ref target_bindings, type_ns_only, .. } =>
(source, target, source_bindings, target_bindings, 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) = 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 = 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);
source_bindings[ns].set(binding);
} else {
return
};
let parent = directive.parent_scope.module;
match source_bindings[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);
target_bindings[ns].set(Some(imported_binding));
this.define(parent, target, ns, imported_binding);
}
}
});
!indeterminate
}
/// 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,
directive: &'b ImportDirective<'b>
) -> Option<UnresolvedImportError> {
self.current_module = directive.parent_scope.module;
let orig_vis = directive.vis.replace(ty::Visibility::Invisible);
let prev_ambiguity_errors_len = self.ambiguity_errors.len();
let path_res = self.resolve_path(&directive.module_path, None, &directive.parent_scope,
true, directive.span, directive.crate_lint());
let no_ambiguity = self.ambiguity_errors.len() == prev_ambiguity_errors_len;
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) && no_ambiguity {
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 { is_error_from_last_segment: false, span, label, suggestion } => {
if no_ambiguity {
assert!(directive.imported_module.get().is_none());
resolve_error(self, span, ResolutionError::FailedToResolve {
label,
suggestion,
});
}
return None;
}
PathResult::Failed { is_error_from_last_segment: true, span, label, suggestion } => {
if no_ambiguity {
assert!(directive.imported_module.get().is_none());
let err = match self.make_path_suggestion(
span,
directive.module_path.clone(),
&directive.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,
)),
}
}
None => {
UnresolvedImportError {
span,
label: Some(label),
note: Vec::new(),
suggestion,
}
}
};
return Some(err);
}
return None;
}
PathResult::NonModule(path_res) if path_res.base_res() == Res::Err => {
if no_ambiguity {
assert!(directive.imported_module.get().is_none());
}
// The error was already reported earlier.
return None;
}
PathResult::Indeterminate | PathResult::NonModule(..) => unreachable!(),
};
let (ident, target, source_bindings, target_bindings, type_ns_only) =
match directive.subclass {
SingleImport { source, target, ref source_bindings,
ref target_bindings, type_ns_only, .. } =>
(source, target, source_bindings, target_bindings, 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(Ident::invalid()));
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(UnresolvedImportError {
span: directive.span,
label: Some(String::from("cannot glob-import a module into itself")),
note: Vec::new(),
suggestion: 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_blacklisted_binding =
mem::replace(&mut this.blacklisted_binding, target_bindings[ns].get());
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;
this.blacklisted_binding = orig_blacklisted_binding;
directive.vis.set(orig_vis);
match binding {
Ok(binding) => {
// Consistency checks, analogous to `finalize_current_module_macro_resolutions`.
let initial_res = source_bindings[ns].get().map(|initial_binding| {
all_ns_err = false;
if let Some(target_binding) = target_bindings[ns].get() {
// Note that as_str() de-gensyms the Symbol
if target.name.as_str() == "_" &&
initial_binding.is_extern_crate() && !initial_binding.is_import() {
this.record_use(ident, ns, target_binding,
directive.module_path.is_empty());
}
}
initial_binding.res()
});
let res = binding.res();
if let Ok(initial_res) = initial_res {
if res != initial_res && this.ambiguity_errors.is_empty() {
span_bug!(directive.span, "inconsistent resolution for an import");
}
} 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.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::Res(Res::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 = find_best_match_for_name(names, &ident.as_str(), 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(
directive, module, ident,
) {
Some((suggestion, note)) => (suggestion.or(lev_suggestion), note),
_ => (lev_suggestion, Vec::new()),
};
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)
}
}
};
Some(UnresolvedImportError {
span: directive.span,
label: Some(label),
note,
suggestion,
})
} 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) = source_bindings[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, &note_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) = source_bindings[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) = source_bindings[ns].get().ok() {
let mut res = binding.res();
if let Res::Def(DefKind::Macro(_), def_id) = res {
// `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 `Res::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");
res = Res::Err;
}
}
this.import_res_map.entry(directive.id).or_default()[ns] = Some(res);
});
self.check_for_redundant_imports(
ident,
directive,
source_bindings,
target_bindings,
target,
);
debug!("(resolving single import) successfully resolved import");
None
}
fn check_for_redundant_imports(
&mut self,
ident: Ident,
directive: &'b ImportDirective<'b>,
source_bindings: &PerNS<Cell<Result<&'b NameBinding<'b>, Determinacy>>>,
target_bindings: &PerNS<Cell<Option<&'b NameBinding<'b>>>>,
target: Ident,
) {
// Skip if the import was produced by a macro.
if directive.parent_scope.expansion != ExpnId::root() {
return;
}
// Skip if we are inside a named module (in contrast to an anonymous
// module defined by a block).
if let ModuleKind::Def(..) = directive.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 Some(binding) = source_bindings[ns].get().ok() {
if binding.res() == Res::Err {
return;
}
let orig_blacklisted_binding = mem::replace(
&mut this.blacklisted_binding,
target_bindings[ns].get()
);
match this.early_resolve_ident_in_lexical_scope(
target,
ScopeSet::Import(ns),
&directive.parent_scope,
false,
false,
directive.span,
) {
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)
}
this.blacklisted_binding = orig_blacklisted_binding;
});
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.session.buffer_lint_with_diagnostic(
UNUSED_IMPORTS,
directive.id,
directive.span,
&format!("the item `{}` is imported redundantly", ident),
BuiltinLintDiagnostics::RedundantImport(redundant_spans, ident),
);
}
}
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 module.is_trait() {
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) {
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_partial_res(directive.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<'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 ambiguous and gensymed imports. Gensymed imports
// (e.g. implicitly injected `std`) cannot be properly encoded in metadata,
// so they can cause name conflict errors downstream.
let is_good_import = binding.is_import() && !binding.is_ambiguity() &&
// Note that as_str() de-gensyms the Symbol
!(ident.is_gensymed() && ident.name.as_str() != "_");
if is_good_import || binding.is_macro_def() {
let res = binding.res();
if res != Res::Err {
if let Some(def_id) = res.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(),
res: res,
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 != 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)
} 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(),
}
}
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