diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index be347253e7f06..20d4ba9c63231 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -38,7 +38,7 @@ use syntax::parse;
use syntax::parse::ParseSess;
use syntax::{ast, source_map};
use syntax::feature_gate::AttributeType;
-use syntax_pos::{MultiSpan, Span};
+use syntax_pos::{MultiSpan, Span, symbol::Symbol};
use util::profiling::SelfProfiler;
use rustc_target::spec::PanicStrategy;
@@ -168,6 +168,10 @@ pub struct Session {
/// Cap lint level specified by a driver specifically.
pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
+
+ /// All the crate names specified with `--extern`, and the builtin ones.
+ /// Starting with the Rust 2018 edition, absolute paths resolve in this set.
+ pub extern_prelude: FxHashSet<Symbol>,
}
pub struct PerfStats {
@@ -1126,6 +1130,18 @@ pub fn build_session_(
CguReuseTracker::new_disabled()
};
+
+ let mut extern_prelude: FxHashSet<Symbol> =
+ sopts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
+
+ // HACK(eddyb) this ignores the `no_{core,std}` attributes.
+ // FIXME(eddyb) warn (somewhere) if core/std is used with `no_{core,std}`.
+ // if !attr::contains_name(&krate.attrs, "no_core") {
+ // if !attr::contains_name(&krate.attrs, "no_std") {
+ extern_prelude.insert(Symbol::intern("core"));
+ extern_prelude.insert(Symbol::intern("std"));
+ extern_prelude.insert(Symbol::intern("meta"));
+
let sess = Session {
target: target_cfg,
host,
@@ -1201,6 +1217,7 @@ pub fn build_session_(
has_global_allocator: Once::new(),
has_panic_handler: Once::new(),
driver_lint_caps: FxHashMap(),
+ extern_prelude,
};
validate_commandline_args_with_session_available(&sess);
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 91b0e9c1dca62..7d5a6bb2a63c3 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -1350,7 +1350,6 @@ pub struct Resolver<'a, 'b: 'a> {
graph_root: Module<'a>,
prelude: Option<Module<'a>>,
- extern_prelude: FxHashSet<Name>,
/// n.b. This is used only for better diagnostics, not name resolution itself.
has_self: FxHashSet<DefId>,
@@ -1663,17 +1662,6 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
DefCollector::new(&mut definitions, Mark::root())
.collect_root(crate_name, session.local_crate_disambiguator());
- let mut extern_prelude: FxHashSet<Name> =
- session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
-
- // HACK(eddyb) this ignore the `no_{core,std}` attributes.
- // FIXME(eddyb) warn (elsewhere) if core/std is used with `no_{core,std}`.
- // if !attr::contains_name(&krate.attrs, "no_core") {
- // if !attr::contains_name(&krate.attrs, "no_std") {
- extern_prelude.insert(Symbol::intern("core"));
- extern_prelude.insert(Symbol::intern("std"));
- extern_prelude.insert(Symbol::intern("meta"));
-
let mut invocations = FxHashMap();
invocations.insert(Mark::root(),
arenas.alloc_invocation_data(InvocationData::root(graph_root)));
@@ -1692,7 +1680,6 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
// AST.
graph_root,
prelude: None,
- extern_prelude,
has_self: FxHashSet(),
field_names: FxHashMap(),
@@ -1963,7 +1950,7 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
if !module.no_implicit_prelude {
// `record_used` means that we don't try to load crates during speculative resolution
- if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
+ if record_used && ns == TypeNS && self.session.extern_prelude.contains(&ident.name) {
let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
self.populate_module_if_necessary(&crate_root);
@@ -3955,7 +3942,7 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
} else {
// Items from the prelude
if !module.no_implicit_prelude {
- names.extend(self.extern_prelude.iter().cloned());
+ names.extend(self.session.extern_prelude.iter().cloned());
if let Some(prelude) = self.prelude {
add_module_candidates(prelude, &mut names);
}
@@ -4401,8 +4388,7 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
);
if self.session.rust_2018() {
- let extern_prelude_names = self.extern_prelude.clone();
- for &name in extern_prelude_names.iter() {
+ for &name in &self.session.extern_prelude {
let ident = Ident::with_empty_ctxt(name);
match self.crate_loader.maybe_process_path_extern(name, ident.span) {
Some(crate_id) => {
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index ed79ff62f176c..7b5e3ca078ba6 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -682,7 +682,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
result
}
WhereToResolve::ExternPrelude => {
- if use_prelude && self.extern_prelude.contains(&ident.name) {
+ if use_prelude && self.session.extern_prelude.contains(&ident.name) {
let crate_id =
self.crate_loader.process_path_extern(ident.name, ident.span);
let crate_root =
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index dc4a76db69266..e689e6d70fdf4 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -199,7 +199,7 @@ impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
if !(
ns == TypeNS &&
!ident.is_path_segment_keyword() &&
- self.extern_prelude.contains(&ident.name)
+ self.session.extern_prelude.contains(&ident.name)
) {
// ... unless the crate name is not in the `extern_prelude`.
return binding;
@@ -218,7 +218,7 @@ impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
} else if
ns == TypeNS &&
!ident.is_path_segment_keyword() &&
- self.extern_prelude.contains(&ident.name)
+ self.session.extern_prelude.contains(&ident.name)
{
let crate_id =
self.crate_loader.process_path_extern(ident.name, ident.span);
@@ -735,7 +735,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
let uniform_paths_feature = self.session.features_untracked().uniform_paths;
for ((span, _, ns), results) in uniform_paths_canaries {
let name = results.name;
- let external_crate = if ns == TypeNS && self.extern_prelude.contains(&name) {
+ let external_crate = if ns == TypeNS && self.session.extern_prelude.contains(&name) {
let crate_id =
self.crate_loader.process_path_extern(name, span);
Some(Def::Mod(DefId { krate: crate_id, index: CRATE_DEF_INDEX }))
diff --git a/src/librustc_typeck/check_unused.rs b/src/librustc_typeck/check_unused.rs
index 5967bd1ba3eea..4b3f08a10ff5e 100644
--- a/src/librustc_typeck/check_unused.rs
+++ b/src/librustc_typeck/check_unused.rs
@@ -130,15 +130,13 @@ fn unused_crates_lint<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) {
});
for extern_crate in &crates_to_lint {
- assert!(extern_crate.def_id.is_local());
+ let id = tcx.hir.as_local_node_id(extern_crate.def_id).unwrap();
+ let item = tcx.hir.expect_item(id);
// If the crate is fully unused, we suggest removing it altogether.
// We do this in any edition.
if extern_crate.warn_if_unused {
if let Some(&span) = unused_extern_crates.get(&extern_crate.def_id) {
- assert_eq!(extern_crate.def_id.krate, LOCAL_CRATE);
- let hir_id = tcx.hir.definitions().def_index_to_hir_id(extern_crate.def_id.index);
- let id = tcx.hir.hir_to_node_id(hir_id);
let msg = "unused extern crate";
tcx.struct_span_lint_node(lint, id, span, msg)
.span_suggestion_short_with_applicability(
@@ -157,6 +155,13 @@ fn unused_crates_lint<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) {
continue;
}
+ // If the extern crate isn't in the extern prelude,
+ // there is no way it can be written as an `use`.
+ let orig_name = extern_crate.orig_name.unwrap_or(item.name);
+ if !tcx.sess.extern_prelude.contains(&orig_name) {
+ continue;
+ }
+
// If the extern crate has any attributes, they may have funky
// semantics we can't faithfully represent using `use` (most
// notably `#[macro_use]`). Ignore it.
@@ -165,9 +170,6 @@ fn unused_crates_lint<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) {
}
// Otherwise, we can convert it into a `use` of some kind.
- let hir_id = tcx.hir.definitions().def_index_to_hir_id(extern_crate.def_id.index);
- let id = tcx.hir.hir_to_node_id(hir_id);
- let item = tcx.hir.expect_item(id);
let msg = "`extern crate` is not idiomatic in the new edition";
let help = format!(
"convert it to a `{}`",
diff --git a/src/test/ui-fulldeps/unnecessary-extern-crate.rs b/src/test/ui-fulldeps/unnecessary-extern-crate.rs
index df723ddf590c4..1cdc9229d078c 100644
--- a/src/test/ui-fulldeps/unnecessary-extern-crate.rs
+++ b/src/test/ui-fulldeps/unnecessary-extern-crate.rs
@@ -20,33 +20,23 @@ extern crate alloc as x;
//~^ ERROR unused extern crate
//~| HELP remove
+extern crate proc_macro;
+
#[macro_use]
extern crate test;
pub extern crate test as y;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `pub use`
pub extern crate libc;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `pub use`
pub(crate) extern crate libc as a;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `pub(crate) use`
crate extern crate libc as b;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `crate use`
mod foo {
pub(in crate::foo) extern crate libc as c;
- //~^ ERROR `extern crate` is not idiomatic in the new edition
- //~| HELP convert it to a `pub(in crate::foo) use`
pub(super) extern crate libc as d;
- //~^ ERROR `extern crate` is not idiomatic in the new edition
- //~| HELP convert it to a `pub(super) use`
extern crate alloc;
//~^ ERROR unused extern crate
@@ -57,12 +47,8 @@ mod foo {
//~| HELP remove
pub extern crate test;
- //~^ ERROR `extern crate` is not idiomatic in the new edition
- //~| HELP convert it
pub extern crate test as y;
- //~^ ERROR `extern crate` is not idiomatic in the new edition
- //~| HELP convert it
mod bar {
extern crate alloc;
@@ -74,8 +60,6 @@ mod foo {
//~| HELP remove
pub(in crate::foo::bar) extern crate libc as e;
- //~^ ERROR `extern crate` is not idiomatic in the new edition
- //~| HELP convert it to a `pub(in crate::foo::bar) use`
fn dummy() {
unsafe {
@@ -96,4 +80,6 @@ mod foo {
fn main() {
unsafe { a::getpid(); }
unsafe { b::getpid(); }
+
+ proc_macro::TokenStream::new();
}
diff --git a/src/test/ui-fulldeps/unnecessary-extern-crate.stderr b/src/test/ui-fulldeps/unnecessary-extern-crate.stderr
index a4307112157b0..58ec5901585d4 100644
--- a/src/test/ui-fulldeps/unnecessary-extern-crate.stderr
+++ b/src/test/ui-fulldeps/unnecessary-extern-crate.stderr
@@ -16,83 +16,29 @@ error: unused extern crate
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:26:1
- |
-LL | pub extern crate test as y;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:30:1
- |
-LL | pub extern crate libc;
- | ^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:34:1
- |
-LL | pub(crate) extern crate libc as a;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(crate) use`
-
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:38:1
- |
-LL | crate extern crate libc as b;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `crate use`
-
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:43:5
- |
-LL | pub(in crate::foo) extern crate libc as c;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(in crate::foo) use`
-
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:47:5
- |
-LL | pub(super) extern crate libc as d;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(super) use`
-
error: unused extern crate
- --> $DIR/unnecessary-extern-crate.rs:51:5
+ --> $DIR/unnecessary-extern-crate.rs:41:5
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
- --> $DIR/unnecessary-extern-crate.rs:55:5
+ --> $DIR/unnecessary-extern-crate.rs:45:5
|
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:59:5
- |
-LL | pub extern crate test;
- | ^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:63:5
- |
-LL | pub extern crate test as y;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
error: unused extern crate
- --> $DIR/unnecessary-extern-crate.rs:68:9
+ --> $DIR/unnecessary-extern-crate.rs:54:9
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
- --> $DIR/unnecessary-extern-crate.rs:72:9
+ --> $DIR/unnecessary-extern-crate.rs:58:9
|
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
-error: `extern crate` is not idiomatic in the new edition
- --> $DIR/unnecessary-extern-crate.rs:76:9
- |
-LL | pub(in crate::foo::bar) extern crate libc as e;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(in crate::foo::bar) use`
-
-error: aborting due to 15 previous errors
+error: aborting due to 6 previous errors
diff --git a/src/test/ui/rust-2018/remove-extern-crate.fixed b/src/test/ui/rust-2018/remove-extern-crate.fixed
index cdae815b200d5..34c7266b637cb 100644
--- a/src/test/ui/rust-2018/remove-extern-crate.fixed
+++ b/src/test/ui/rust-2018/remove-extern-crate.fixed
@@ -14,6 +14,7 @@
// aux-build:remove-extern-crate.rs
// compile-flags:--extern remove_extern_crate
+#![feature(alloc)]
#![warn(rust_2018_idioms)]
@@ -22,11 +23,16 @@ use remove_extern_crate;
#[macro_use]
extern crate remove_extern_crate as something_else;
+// Shouldn't suggest changing to `use`, as the `alloc`
+// crate is not in the extern prelude - see #54381.
+extern crate alloc;
+
fn main() {
another_name::mem::drop(3);
another::foo();
remove_extern_crate::foo!();
bar!();
+ alloc::vec![5];
}
mod another {
diff --git a/src/test/ui/rust-2018/remove-extern-crate.rs b/src/test/ui/rust-2018/remove-extern-crate.rs
index 4984da802c05b..570bbb02f7218 100644
--- a/src/test/ui/rust-2018/remove-extern-crate.rs
+++ b/src/test/ui/rust-2018/remove-extern-crate.rs
@@ -14,6 +14,7 @@
// aux-build:remove-extern-crate.rs
// compile-flags:--extern remove_extern_crate
+#![feature(alloc)]
#![warn(rust_2018_idioms)]
extern crate core;
@@ -22,11 +23,16 @@ use remove_extern_crate;
#[macro_use]
extern crate remove_extern_crate as something_else;
+// Shouldn't suggest changing to `use`, as the `alloc`
+// crate is not in the extern prelude - see #54381.
+extern crate alloc;
+
fn main() {
another_name::mem::drop(3);
another::foo();
remove_extern_crate::foo!();
bar!();
+ alloc::vec![5];
}
mod another {
diff --git a/src/test/ui/rust-2018/remove-extern-crate.stderr b/src/test/ui/rust-2018/remove-extern-crate.stderr
index 064a853625f74..847ba5f3544b2 100644
--- a/src/test/ui/rust-2018/remove-extern-crate.stderr
+++ b/src/test/ui/rust-2018/remove-extern-crate.stderr
@@ -1,24 +1,24 @@
warning: unused extern crate
- --> $DIR/remove-extern-crate.rs:19:1
+ --> $DIR/remove-extern-crate.rs:20:1
|
LL | extern crate core;
| ^^^^^^^^^^^^^^^^^^ help: remove it
|
note: lint level defined here
- --> $DIR/remove-extern-crate.rs:17:9
+ --> $DIR/remove-extern-crate.rs:18:9
|
LL | #![warn(rust_2018_idioms)]
| ^^^^^^^^^^^^^^^^
= note: #[warn(unused_extern_crates)] implied by #[warn(rust_2018_idioms)]
warning: `extern crate` is not idiomatic in the new edition
- --> $DIR/remove-extern-crate.rs:20:1
+ --> $DIR/remove-extern-crate.rs:21:1
|
LL | extern crate core as another_name;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `use`
warning: `extern crate` is not idiomatic in the new edition
- --> $DIR/remove-extern-crate.rs:33:5
+ --> $DIR/remove-extern-crate.rs:39:5
|
LL | extern crate core;
| ^^^^^^^^^^^^^^^^^^ help: convert it to a `use`