rust/src/librustc_resolve/resolve_imports.rs

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// 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::*;
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use DefModifiers;
use Module;
use Namespace::{self, TypeNS, ValueNS};
use {NameBindings, NameBinding};
use NamespaceResult::{BoundResult, UnboundResult, UnknownResult};
use NamespaceResult;
use NameSearchType;
use ResolveResult;
use Resolver;
use UseLexicalScopeFlag;
use {names_to_string, module_to_string};
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use {resolve_error, ResolutionError};
use build_reduced_graph;
use rustc::lint;
use rustc::middle::def::*;
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use rustc::middle::def_id::DefId;
use rustc::middle::privacy::*;
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use syntax::ast::{NodeId, Name};
use syntax::attr::AttrMetaMethods;
use syntax::codemap::Span;
use syntax::util::lev_distance::find_best_match_for_name;
use std::mem::replace;
/// Contains data for specific types of import directives.
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#[derive(Copy, Clone,Debug)]
pub enum ImportDirectiveSubclass {
SingleImport(Name /* target */, Name /* source */),
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GlobImport,
}
/// Whether an import can be shadowed by another import.
#[derive(Debug,PartialEq,Clone,Copy)]
pub enum Shadowable {
Always,
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Never,
}
/// One import directive.
#[derive(Debug)]
pub struct ImportDirective {
pub module_path: Vec<Name>,
pub subclass: ImportDirectiveSubclass,
pub span: Span,
pub id: NodeId,
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pub is_public: bool, // see note in ImportResolutionPerNamespace about how to use this
pub shadowable: Shadowable,
}
impl ImportDirective {
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pub fn new(module_path: Vec<Name>,
subclass: ImportDirectiveSubclass,
span: Span,
id: NodeId,
is_public: bool,
shadowable: Shadowable)
-> ImportDirective {
ImportDirective {
module_path: module_path,
subclass: subclass,
span: span,
id: id,
is_public: is_public,
shadowable: shadowable,
}
}
}
/// The item that an import resolves to.
#[derive(Clone,Debug)]
pub struct Target<'a> {
pub target_module: Module<'a>,
pub binding: NameBinding<'a>,
pub shadowable: Shadowable,
}
impl<'a> Target<'a> {
pub fn new(target_module: Module<'a>, binding: NameBinding<'a>, shadowable: Shadowable)
-> Self {
Target {
target_module: target_module,
binding: binding,
shadowable: shadowable,
}
}
}
#[derive(Debug)]
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/// An ImportResolutionPerNamespace records what we know about an imported name.
/// More specifically, it records the number of unresolved `use` directives that import the name,
/// and for each namespace, it records the `use` directive importing the name in the namespace
/// and the `Target` to which the name in the namespace resolves (if applicable).
/// Different `use` directives may import the same name in different namespaces.
pub struct ImportResolutionPerNamespace<'a> {
// When outstanding_references reaches zero, outside modules can count on the targets being
// correct. Before then, all bets are off; future `use` directives could override the name.
// Since shadowing is forbidden, the only way outstanding_references > 1 in a legal program
// is if the name is imported by exactly two `use` directives, one of which resolves to a
// value and the other of which resolves to a type.
pub outstanding_references: usize,
pub type_ns: ImportResolution<'a>,
pub value_ns: ImportResolution<'a>,
}
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/// Records what we know about an imported name in a namespace (see `ImportResolutionPerNamespace`).
#[derive(Clone,Debug)]
pub struct ImportResolution<'a> {
/// Whether the name in the namespace was imported with a `use` or a `pub use`.
pub is_public: bool,
/// Resolution of the name in the namespace
pub target: Option<Target<'a>>,
/// The source node of the `use` directive
pub id: NodeId,
}
impl<'a> ::std::ops::Index<Namespace> for ImportResolutionPerNamespace<'a> {
type Output = ImportResolution<'a>;
fn index(&self, ns: Namespace) -> &ImportResolution<'a> {
match ns { TypeNS => &self.type_ns, ValueNS => &self.value_ns }
}
}
impl<'a> ::std::ops::IndexMut<Namespace> for ImportResolutionPerNamespace<'a> {
fn index_mut(&mut self, ns: Namespace) -> &mut ImportResolution<'a> {
match ns { TypeNS => &mut self.type_ns, ValueNS => &mut self.value_ns }
}
}
impl<'a> ImportResolutionPerNamespace<'a> {
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pub fn new(id: NodeId, is_public: bool) -> Self {
let resolution = ImportResolution { id: id, is_public: is_public, target: None };
ImportResolutionPerNamespace {
outstanding_references: 0, type_ns: resolution.clone(), value_ns: resolution,
}
}
pub fn shadowable(&self, namespace: Namespace) -> Shadowable {
match self[namespace].target {
Some(ref target) => target.shadowable,
None => Shadowable::Always,
}
}
}
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struct ImportResolvingError {
span: Span,
path: String,
help: String,
}
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struct ImportResolver<'a, 'b: 'a, 'tcx: 'b> {
resolver: &'a mut Resolver<'b, 'tcx>,
}
impl<'a, 'b:'a, 'tcx:'b> ImportResolver<'a, 'b, 'tcx> {
// 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.
fn resolve_imports(&mut self) {
let mut i = 0;
let mut prev_unresolved_imports = 0;
loop {
debug!("(resolving imports) iteration {}, {} imports left",
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i,
self.resolver.unresolved_imports);
let module_root = self.resolver.graph_root;
let errors = self.resolve_imports_for_module_subtree(module_root);
if self.resolver.unresolved_imports == 0 {
debug!("(resolving imports) success");
break;
}
if self.resolver.unresolved_imports == prev_unresolved_imports {
// resolving failed
if errors.len() > 0 {
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for e in errors {
resolve_error(self.resolver,
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e.span,
ResolutionError::UnresolvedImport(Some((&e.path, &e.help))));
}
} else {
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// Report unresolved imports only if no hard error was already reported
// to avoid generating multiple errors on the same import.
// Imports that are still indeterminate at this point are actually blocked
// by errored imports, so there is no point reporting them.
self.resolver.report_unresolved_imports(module_root);
}
break;
}
i += 1;
prev_unresolved_imports = self.resolver.unresolved_imports;
}
}
/// Attempts to resolve imports for the given module and all of its
/// submodules.
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fn resolve_imports_for_module_subtree(&mut self,
module_: Module<'b>)
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-> Vec<ImportResolvingError> {
let mut errors = Vec::new();
debug!("(resolving imports for module subtree) resolving {}",
module_to_string(&*module_));
let orig_module = replace(&mut self.resolver.current_module, module_);
errors.extend(self.resolve_imports_for_module(module_));
self.resolver.current_module = orig_module;
build_reduced_graph::populate_module_if_necessary(self.resolver, &module_);
for (_, child_node) in module_.children.borrow().iter() {
match child_node.type_ns.module() {
None => {
// Nothing to do.
}
Some(child_module) => {
errors.extend(self.resolve_imports_for_module_subtree(child_module));
}
}
}
for (_, child_module) in module_.anonymous_children.borrow().iter() {
errors.extend(self.resolve_imports_for_module_subtree(child_module));
}
errors
}
/// Attempts to resolve imports for the given module only.
fn resolve_imports_for_module(&mut self, module: Module<'b>) -> Vec<ImportResolvingError> {
let mut errors = Vec::new();
if module.all_imports_resolved() {
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debug!("(resolving imports for module) all imports resolved for {}",
module_to_string(&*module));
return errors;
}
let mut imports = module.imports.borrow_mut();
let import_count = imports.len();
let mut indeterminate_imports = Vec::new();
while module.resolved_import_count.get() + indeterminate_imports.len() < import_count {
let import_index = module.resolved_import_count.get();
match self.resolve_import_for_module(module, &imports[import_index]) {
ResolveResult::Failed(err) => {
let import_directive = &imports[import_index];
let (span, help) = match err {
Some((span, msg)) => (span, format!(". {}", msg)),
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None => (import_directive.span, String::new()),
};
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errors.push(ImportResolvingError {
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span: span,
path: import_path_to_string(&import_directive.module_path,
import_directive.subclass),
help: help,
});
}
ResolveResult::Indeterminate => {}
ResolveResult::Success(()) => {
// count success
module.resolved_import_count
.set(module.resolved_import_count.get() + 1);
continue;
}
}
// This resolution was not successful, keep it for later
indeterminate_imports.push(imports.swap_remove(import_index));
}
imports.extend(indeterminate_imports);
errors
}
/// Attempts to resolve the given import. The return value indicates
/// failure if we're certain the name does not exist, indeterminate if we
/// don't know whether the name exists at the moment due to other
/// currently-unresolved imports, or success if we know the name exists.
/// If successful, the resolved bindings are written into the module.
fn resolve_import_for_module(&mut self,
module_: Module<'b>,
import_directive: &ImportDirective)
-> ResolveResult<()> {
let mut resolution_result = ResolveResult::Failed(None);
let module_path = &import_directive.module_path;
debug!("(resolving import for module) resolving import `{}::...` in `{}`",
names_to_string(&module_path[..]),
module_to_string(&*module_));
// First, resolve the module path for the directive, if necessary.
let container = if module_path.is_empty() {
// Use the crate root.
Some((self.resolver.graph_root, LastMod(AllPublic)))
} else {
match self.resolver.resolve_module_path(module_,
&module_path[..],
UseLexicalScopeFlag::DontUseLexicalScope,
import_directive.span,
NameSearchType::ImportSearch) {
ResolveResult::Failed(err) => {
resolution_result = ResolveResult::Failed(err);
None
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}
ResolveResult::Indeterminate => {
resolution_result = ResolveResult::Indeterminate;
None
}
ResolveResult::Success(container) => Some(container),
}
};
match container {
None => {}
Some((containing_module, lp)) => {
// We found the module that the target is contained
// within. Attempt to resolve the import within it.
match import_directive.subclass {
SingleImport(target, source) => {
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resolution_result = self.resolve_single_import(&module_,
containing_module,
target,
source,
import_directive,
lp);
}
GlobImport => {
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resolution_result = self.resolve_glob_import(&module_,
containing_module,
import_directive,
lp);
}
}
}
}
// Decrement the count of unresolved imports.
match resolution_result {
ResolveResult::Success(()) => {
assert!(self.resolver.unresolved_imports >= 1);
self.resolver.unresolved_imports -= 1;
}
_ => {
// Nothing to do here; just return the error.
}
}
// Decrement the count of unresolved globs if necessary. But only if
// the resolution result is a success -- other cases will
// be handled by the main loop.
if resolution_result.success() {
match import_directive.subclass {
GlobImport => {
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module_.dec_glob_count();
if import_directive.is_public {
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module_.dec_pub_glob_count();
}
}
SingleImport(..) => {
// Ignore.
}
}
if import_directive.is_public {
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module_.dec_pub_count();
}
}
return resolution_result;
}
fn resolve_single_import(&mut self,
module_: Module<'b>,
target_module: Module<'b>,
target: Name,
source: Name,
directive: &ImportDirective,
lp: LastPrivate)
-> ResolveResult<()> {
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debug!("(resolving single import) resolving `{}` = `{}::{}` from `{}` id {}, last \
private {:?}",
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target,
module_to_string(&*target_module),
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source,
module_to_string(module_),
directive.id,
lp);
let lp = match lp {
LastMod(lp) => lp,
LastImport {..} => {
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self.resolver
.session
.span_bug(directive.span, "not expecting Import here, must be LastMod")
}
};
// We need to resolve both namespaces for this to succeed.
let mut value_result = UnknownResult;
let mut type_result = UnknownResult;
let mut lev_suggestion = "".to_owned();
// Search for direct children of the containing module.
build_reduced_graph::populate_module_if_necessary(self.resolver, &target_module);
match target_module.children.borrow().get(&source) {
None => {
let names = target_module.children.borrow();
if let Some(name) = find_best_match_for_name(names.keys(),
&source.as_str(),
None) {
lev_suggestion = format!(". Did you mean to use `{}`?", name);
}
}
Some(ref child_name_bindings) => {
// pub_err makes sure we don't give the same error twice.
let mut pub_err = false;
if child_name_bindings.value_ns.defined() {
debug!("(resolving single import) found value binding");
value_result = BoundResult(target_module,
child_name_bindings.value_ns.clone());
if directive.is_public && !child_name_bindings.value_ns.is_public() {
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let msg = format!("`{}` is private, and cannot be reexported", source);
let note_msg = format!("Consider marking `{}` as `pub` in the imported \
module",
source);
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struct_span_err!(self.resolver.session, directive.span, E0364, "{}", &msg)
.span_note(directive.span, &note_msg)
.emit();
pub_err = true;
}
if directive.is_public && child_name_bindings.value_ns.
defined_with(DefModifiers::PRIVATE_VARIANT) {
let msg = format!("variant `{}` is private, and cannot be reexported ( \
error E0364), consider declaring its enum as `pub`",
source);
self.resolver.session.add_lint(lint::builtin::PRIVATE_IN_PUBLIC,
directive.id,
directive.span,
msg);
pub_err = true;
}
}
if child_name_bindings.type_ns.defined() {
debug!("(resolving single import) found type binding");
type_result = BoundResult(target_module,
child_name_bindings.type_ns.clone());
if !pub_err && directive.is_public &&
!child_name_bindings.type_ns.is_public() {
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let msg = format!("`{}` is private, and cannot be reexported", source);
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let note_msg = format!("Consider declaring module `{}` as a `pub mod`",
source);
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struct_span_err!(self.resolver.session, directive.span, E0365, "{}", &msg)
.span_note(directive.span, &note_msg)
.emit();
}
if !pub_err && directive.is_public && child_name_bindings.type_ns.
defined_with(DefModifiers::PRIVATE_VARIANT) {
let msg = format!("variant `{}` is private, and cannot be reexported ( \
error E0365), consider declaring its enum as `pub`",
source);
self.resolver.session.add_lint(lint::builtin::PRIVATE_IN_PUBLIC,
directive.id,
directive.span,
msg);
}
}
}
}
// Unless we managed to find a result in both namespaces (unlikely),
// search imports as well.
let mut value_used_reexport = false;
let mut type_used_reexport = false;
match (value_result.clone(), type_result.clone()) {
(BoundResult(..), BoundResult(..)) => {} // Continue.
_ => {
// If there is an unresolved glob at this point in the
// containing module, bail out. We don't know enough to be
// able to resolve this import.
if target_module.pub_glob_count.get() > 0 {
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debug!("(resolving single import) unresolved pub glob; bailing out");
return ResolveResult::Indeterminate;
}
// Now search the exported imports within the containing module.
match target_module.import_resolutions.borrow().get(&source) {
None => {
debug!("(resolving single import) no import");
// The containing module definitely doesn't have an
// exported import with the name in question. We can
// therefore accurately report that the names are
// unbound.
if lev_suggestion.is_empty() { // skip if we already have a suggestion
let names = target_module.import_resolutions.borrow();
if let Some(name) = find_best_match_for_name(names.keys(),
&source.as_str(),
None) {
lev_suggestion =
format!(". Did you mean to use the re-exported import `{}`?",
name);
}
}
if value_result.is_unknown() {
value_result = UnboundResult;
}
if type_result.is_unknown() {
type_result = UnboundResult;
}
}
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Some(import_resolution) if import_resolution.outstanding_references == 0 => {
fn get_binding<'a>(this: &mut Resolver,
import_resolution: &ImportResolutionPerNamespace<'a>,
namespace: Namespace,
source: Name)
-> NamespaceResult<'a> {
// Import resolutions must be declared with "pub"
// in order to be exported.
if !import_resolution[namespace].is_public {
return UnboundResult;
}
match import_resolution[namespace].target.clone() {
None => {
return UnboundResult;
}
Some(Target {
target_module,
binding,
shadowable: _
}) => {
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debug!("(resolving single import) found import in ns {:?}",
namespace);
let id = import_resolution[namespace].id;
// track used imports and extern crates as well
this.used_imports.insert((id, namespace));
this.record_import_use(id, source);
match target_module.def_id() {
Some(DefId{krate: kid, ..}) => {
this.used_crates.insert(kid);
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}
_ => {}
}
return BoundResult(target_module, binding);
}
}
}
// The name is an import which has been fully
// resolved. We can, therefore, just follow it.
if value_result.is_unknown() {
value_result = get_binding(self.resolver,
import_resolution,
ValueNS,
source);
value_used_reexport = import_resolution.value_ns.is_public;
}
if type_result.is_unknown() {
type_result = get_binding(self.resolver,
import_resolution,
TypeNS,
source);
type_used_reexport = import_resolution.type_ns.is_public;
}
}
Some(_) => {
// If target_module is the same module whose import we are resolving
// and there it has an unresolved import with the same name as `source`,
// then the user is actually trying to import an item that is declared
// in the same scope
//
// e.g
// use self::submodule;
// pub mod submodule;
//
// In this case we continue as if we resolved the import and let the
// check_for_conflicts_between_imports_and_items call below handle
// the conflict
match (module_.def_id(), target_module.def_id()) {
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(Some(id1), Some(id2)) if id1 == id2 => {
if value_result.is_unknown() {
value_result = UnboundResult;
}
if type_result.is_unknown() {
type_result = UnboundResult;
}
}
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_ => {
// The import is unresolved. Bail out.
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debug!("(resolving single import) unresolved import; bailing out");
return ResolveResult::Indeterminate;
}
}
}
}
}
}
let mut value_used_public = false;
let mut type_used_public = false;
// If we didn't find a result in the type namespace, search the
// external modules.
match type_result {
BoundResult(..) => {}
_ => {
match target_module.external_module_children.borrow_mut().get(&source) {
None => {} // Continue.
Some(module) => {
debug!("(resolving single import) found external module");
// track the module as used.
match module.def_id() {
Some(DefId{krate: kid, ..}) => {
self.resolver.used_crates.insert(kid);
}
_ => {}
}
let name_binding = NameBinding::create_from_module(module);
type_result = BoundResult(target_module, name_binding);
type_used_public = true;
}
}
}
}
// We've successfully resolved the import. Write the results in.
let mut import_resolutions = module_.import_resolutions.borrow_mut();
let import_resolution = import_resolutions.get_mut(&target).unwrap();
{
let mut check_and_write_import = |namespace, result: &_, used_public: &mut bool| {
let namespace_name = match namespace {
TypeNS => "type",
ValueNS => "value",
};
match *result {
BoundResult(ref target_module, ref name_binding) => {
debug!("(resolving single import) found {:?} target: {:?}",
namespace_name,
name_binding.def());
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self.check_for_conflicting_import(&import_resolution,
directive.span,
target,
namespace);
self.check_that_import_is_importable(&name_binding,
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directive.span,
target);
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import_resolution[namespace] = ImportResolution {
target: Some(Target::new(target_module,
name_binding.clone(),
directive.shadowable)),
id: directive.id,
is_public: directive.is_public
};
self.add_export(module_, target, &import_resolution[namespace]);
*used_public = name_binding.is_public();
}
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UnboundResult => {
// Continue.
}
UnknownResult => {
panic!("{:?} result should be known at this point", namespace_name);
}
}
};
check_and_write_import(ValueNS, &value_result, &mut value_used_public);
check_and_write_import(TypeNS, &type_result, &mut type_used_public);
}
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self.check_for_conflicts_between_imports_and_items(module_,
import_resolution,
directive.span,
target);
if value_result.is_unbound() && type_result.is_unbound() {
let msg = format!("There is no `{}` in `{}`{}",
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source,
module_to_string(&target_module), lev_suggestion);
return ResolveResult::Failed(Some((directive.span, msg)));
}
let value_used_public = value_used_reexport || value_used_public;
let type_used_public = type_used_reexport || type_used_public;
assert!(import_resolution.outstanding_references >= 1);
import_resolution.outstanding_references -= 1;
// 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.
let value_def_and_priv = import_resolution.value_ns.target.as_ref().map(|target| {
let def = target.binding.def().unwrap();
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(def,
if value_used_public {
lp
} else {
DependsOn(def.def_id())
})
});
let type_def_and_priv = import_resolution.type_ns.target.as_ref().map(|target| {
let def = target.binding.def().unwrap();
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(def,
if type_used_public {
lp
} else {
DependsOn(def.def_id())
})
});
let import_lp = LastImport {
value_priv: value_def_and_priv.map(|(_, p)| p),
value_used: Used,
type_priv: type_def_and_priv.map(|(_, p)| p),
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type_used: Used,
};
if let Some((def, _)) = value_def_and_priv {
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self.resolver.def_map.borrow_mut().insert(directive.id,
PathResolution {
base_def: def,
last_private: import_lp,
depth: 0,
});
}
if let Some((def, _)) = type_def_and_priv {
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self.resolver.def_map.borrow_mut().insert(directive.id,
PathResolution {
base_def: def,
last_private: import_lp,
depth: 0,
});
}
debug!("(resolving single import) successfully resolved import");
return ResolveResult::Success(());
}
// Resolves a glob import. Note that this function cannot fail; it either
// succeeds or bails out (as importing * from an empty module or a module
// that exports nothing is valid). target_module is the module we are
// actually importing, i.e., `foo` in `use foo::*`.
fn resolve_glob_import(&mut self,
module_: Module<'b>,
target_module: Module<'b>,
import_directive: &ImportDirective,
lp: LastPrivate)
-> ResolveResult<()> {
let id = import_directive.id;
let is_public = import_directive.is_public;
// This function works in a highly imperative manner; it eagerly adds
// everything it can to the list of import resolutions of the module
// node.
debug!("(resolving glob import) resolving glob import {}", id);
// We must bail out if the node has unresolved imports of any kind
// (including globs).
if (*target_module).pub_count.get() > 0 {
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debug!("(resolving glob import) target module has unresolved pub imports; bailing out");
return ResolveResult::Indeterminate;
}
// Add all resolved imports from the containing module.
let import_resolutions = target_module.import_resolutions.borrow();
if module_.import_resolutions.borrow_state() != ::std::cell::BorrowState::Unused {
// In this case, target_module == module_
// This means we are trying to glob import a module into itself,
// and it is a no-go
debug!("(resolving glob imports) target module is current module; giving up");
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return ResolveResult::Failed(Some((import_directive.span,
"Cannot glob-import a module into itself.".into())));
}
for (name, target_import_resolution) in import_resolutions.iter() {
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debug!("(resolving glob import) writing module resolution {} into `{}`",
*name,
module_to_string(module_));
// Here we merge two import resolutions.
let mut import_resolutions = module_.import_resolutions.borrow_mut();
let mut dest_import_resolution = import_resolutions.entry(*name).or_insert_with(|| {
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ImportResolutionPerNamespace::new(id, is_public)
});
for &ns in [TypeNS, ValueNS].iter() {
match target_import_resolution[ns].target {
Some(ref target) if target_import_resolution[ns].is_public => {
self.check_for_conflicting_import(&dest_import_resolution,
import_directive.span,
*name,
ns);
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dest_import_resolution[ns] = ImportResolution {
id: id, is_public: is_public, target: Some(target.clone())
};
self.add_export(module_, *name, &dest_import_resolution[ns]);
}
_ => {}
}
}
}
// Add all children from the containing module.
build_reduced_graph::populate_module_if_necessary(self.resolver, &target_module);
for (&name, name_bindings) in target_module.children.borrow().iter() {
self.merge_import_resolution(module_,
target_module,
import_directive,
name,
name_bindings.clone());
}
// Record the destination of this import
if let Some(did) = target_module.def_id() {
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self.resolver.def_map.borrow_mut().insert(id,
PathResolution {
base_def: Def::Mod(did),
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last_private: lp,
depth: 0,
});
}
debug!("(resolving glob import) successfully resolved import");
return ResolveResult::Success(());
}
fn merge_import_resolution(&mut self,
module_: Module<'b>,
containing_module: Module<'b>,
import_directive: &ImportDirective,
name: Name,
name_bindings: NameBindings<'b>) {
let id = import_directive.id;
let is_public = import_directive.is_public;
let mut import_resolutions = module_.import_resolutions.borrow_mut();
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let dest_import_resolution = import_resolutions.entry(name).or_insert_with(|| {
ImportResolutionPerNamespace::new(id, is_public)
});
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debug!("(resolving glob import) writing resolution `{}` in `{}` to `{}`",
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name,
module_to_string(&*containing_module),
module_to_string(module_));
// Merge the child item into the import resolution.
// pub_err makes sure we don't give the same error twice.
let mut pub_err = false;
{
let mut merge_child_item = |namespace| {
if !pub_err && is_public &&
name_bindings[namespace].defined_with(DefModifiers::PRIVATE_VARIANT) {
let msg = format!("variant `{}` is private, and cannot be reexported (error \
E0364), consider declaring its enum as `pub`", name);
self.resolver.session.add_lint(lint::builtin::PRIVATE_IN_PUBLIC,
import_directive.id,
import_directive.span,
msg);
pub_err = true;
}
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let modifier = DefModifiers::IMPORTABLE | DefModifiers::PUBLIC;
if name_bindings[namespace].defined_with(modifier) {
let namespace_name = match namespace {
TypeNS => "type",
ValueNS => "value",
};
debug!("(resolving glob import) ... for {} target", namespace_name);
if dest_import_resolution.shadowable(namespace) == Shadowable::Never {
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let msg = format!("a {} named `{}` has already been imported in this \
module",
namespace_name,
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name);
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span_err!(self.resolver.session,
import_directive.span,
E0251,
"{}",
msg);
} else {
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dest_import_resolution[namespace] = ImportResolution {
target: Some(Target::new(containing_module,
name_bindings[namespace].clone(),
import_directive.shadowable)),
id: id,
is_public: is_public
};
self.add_export(module_, name, &dest_import_resolution[namespace]);
}
} else {
// FIXME #30159: This is required for backwards compatability.
dest_import_resolution[namespace].is_public |= is_public;
}
};
merge_child_item(ValueNS);
merge_child_item(TypeNS);
}
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self.check_for_conflicts_between_imports_and_items(module_,
dest_import_resolution,
import_directive.span,
name);
}
fn add_export(&mut self, module: Module<'b>, name: Name, resolution: &ImportResolution<'b>) {
if !resolution.is_public { return }
let node_id = match module.def_id() {
Some(def_id) => self.resolver.ast_map.as_local_node_id(def_id).unwrap(),
None => return,
};
let export = match resolution.target.as_ref().unwrap().binding.def() {
Some(def) => Export { name: name, def_id: def.def_id() },
None => return,
};
self.resolver.export_map.entry(node_id).or_insert(Vec::new()).push(export);
}
/// Checks that imported names and items don't have the same name.
fn check_for_conflicting_import(&mut self,
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import_resolution: &ImportResolutionPerNamespace,
import_span: Span,
name: Name,
namespace: Namespace) {
let target = &import_resolution[namespace].target;
debug!("check_for_conflicting_import: {}; target exists: {}",
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name,
target.is_some());
match *target {
Some(ref target) if target.shadowable != Shadowable::Always => {
let ns_word = match namespace {
TypeNS => {
match target.binding.module() {
Some(ref module) if module.is_normal() => "module",
Some(ref module) if module.is_trait() => "trait",
_ => "type",
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}
}
ValueNS => "value",
};
let use_id = import_resolution[namespace].id;
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let item = self.resolver.ast_map.expect_item(use_id);
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let mut err = struct_span_err!(self.resolver.session,
import_span,
E0252,
"a {} named `{}` has already been imported \
in this module",
ns_word,
name);
span_note!(&mut err,
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item.span,
"previous import of `{}` here",
name);
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err.emit();
}
Some(_) | None => {}
}
}
/// Checks that an import is actually importable
fn check_that_import_is_importable(&mut self,
name_binding: &NameBinding,
import_span: Span,
name: Name) {
if !name_binding.defined_with(DefModifiers::IMPORTABLE) {
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let msg = format!("`{}` is not directly importable", name);
span_err!(self.resolver.session, import_span, E0253, "{}", &msg[..]);
}
}
/// Checks that imported names and items don't have the same name.
fn check_for_conflicts_between_imports_and_items(&mut self,
module: Module<'b>,
import: &ImportResolutionPerNamespace<'b>,
import_span: Span,
name: Name) {
// First, check for conflicts between imports and `extern crate`s.
if module.external_module_children
.borrow()
.contains_key(&name) {
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match import.type_ns.target {
Some(ref target) if target.shadowable != Shadowable::Always => {
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let msg = format!("import `{0}` conflicts with imported crate in this module \
(maybe you meant `use {0}::*`?)",
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name);
span_err!(self.resolver.session, import_span, E0254, "{}", &msg[..]);
}
Some(_) | None => {}
}
}
// Check for item conflicts.
let name_bindings = match module.children.borrow().get(&name) {
None => {
// There can't be any conflicts.
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return;
}
Some(ref name_bindings) => (*name_bindings).clone(),
};
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match import.value_ns.target {
Some(ref target) if target.shadowable != Shadowable::Always => {
if let Some(ref value) = *name_bindings.value_ns.borrow() {
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let mut err = struct_span_err!(self.resolver.session,
import_span,
E0255,
"import `{}` conflicts with \
value in this module",
name);
if let Some(span) = value.span {
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err.span_note(span, "conflicting value here");
}
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err.emit();
}
}
Some(_) | None => {}
}
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match import.type_ns.target {
Some(ref target) if target.shadowable != Shadowable::Always => {
if let Some(ref ty) = *name_bindings.type_ns.borrow() {
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let (what, note) = match ty.module() {
Some(ref module) if module.is_normal() =>
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("existing submodule", "note conflicting module here"),
Some(ref module) if module.is_trait() =>
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("trait in this module", "note conflicting trait here"),
_ => ("type in this module", "note conflicting type here"),
};
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let mut err = struct_span_err!(self.resolver.session,
import_span,
E0256,
"import `{}` conflicts with {}",
name,
what);
if let Some(span) = ty.span {
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err.span_note(span, note);
}
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err.emit();
}
}
Some(_) | None => {}
}
}
}
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fn import_path_to_string(names: &[Name], subclass: ImportDirectiveSubclass) -> String {
if names.is_empty() {
import_directive_subclass_to_string(subclass)
} else {
(format!("{}::{}",
names_to_string(names),
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import_directive_subclass_to_string(subclass)))
.to_string()
}
}
fn import_directive_subclass_to_string(subclass: ImportDirectiveSubclass) -> String {
match subclass {
SingleImport(_, source) => source.to_string(),
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GlobImport => "*".to_string(),
}
}
pub fn resolve_imports(resolver: &mut Resolver) {
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let mut import_resolver = ImportResolver { resolver: resolver };
import_resolver.resolve_imports();
}