Auto merge of #56032 - petrochenkov:stabecip, r=nikomatsakis

Stabilize `extern_crate_item_prelude` Closes #55599

Author: bors

src/librustc_resolve/lib.rs

@@ -58,7 +58,6 @@ use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
 use syntax::ext::base::SyntaxExtension;
 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
 use syntax::ext::base::MacroKind;
-use syntax::feature_gate::{emit_feature_err, GateIssue};
 use syntax::symbol::{Symbol, keywords};
 use syntax::util::lev_distance::find_best_match_for_name;
 
@@ -2115,7 +2114,7 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
 
  if !module.no_implicit_prelude {
  if ns == TypeNS {
- if let Some(binding) = self.extern_prelude_get(ident, !record_used, false) {
+ if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
  return Some(LexicalScopeBinding::Item(binding));
  }
  }
@@ -5022,21 +5021,14 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
  self.name_already_seen.insert(name, span);
  }
 
- fn extern_prelude_get(&mut self, ident: Ident, speculative: bool, skip_feature_gate: bool)
+ fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
  -> Option<&'a NameBinding<'a>> {
  if ident.is_path_segment_keyword() {
  // Make sure `self`, `super` etc produce an error when passed to here.
  return None;
  }
  self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
  if let Some(binding) = entry.extern_crate_item {
- if !speculative && !skip_feature_gate && entry.introduced_by_item &&
- !self.session.features_untracked().extern_crate_item_prelude {
- emit_feature_err(&self.session.parse_sess, "extern_crate_item_prelude",
- ident.span, GateIssue::Language,
- "use of extern prelude names introduced \
- with `extern crate` items is unstable");
- }
  Some(binding)
  } else {
  let crate_id = if !speculative {

src/librustc_resolve/macros.rs

@@ -738,8 +738,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
  }
  WhereToResolve::ExternPrelude => {
  if use_prelude {
- match self.extern_prelude_get(ident, !record_used,
- innermost_result.is_some()) {
+ match self.extern_prelude_get(ident, !record_used) {
  Some(binding) => Ok((binding, Flags::PRELUDE)),
  None => Err(Determinacy::determined(
  self.graph_root.unresolved_invocations.borrow().is_empty()
@@ -906,7 +905,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
  // but its `Def` should coincide with a crate passed with `--extern`
  // (otherwise there would be ambiguity) and we can skip feature error in this case.
  if ns != TypeNS || !use_prelude ||
- self.extern_prelude_get(ident, true, false).is_none() {
+ self.extern_prelude_get(ident, true).is_none() {
  let msg = "imports can only refer to extern crate names \
  passed with `--extern` on stable channel";
  let mut err = feature_err(&self.session.parse_sess, "uniform_paths",

src/librustc_resolve/resolve_imports.rs

@@ -166,8 +166,7 @@ impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
  assert!(!restricted_shadowing);
  match uniform_root_kind {
  UniformRootKind::ExternPrelude => {
- return if let Some(binding) =
- self.extern_prelude_get(ident, !record_used, false) {
+ return 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.

src/libsyntax/feature_gate.rs

@@ -499,9 +499,6 @@ declare_features! (
  // Allows `const _: TYPE = VALUE`
  (active, underscore_const_names, "1.31.0", Some(54912), None),
 
- // `extern crate foo as bar;` puts `bar` into extern prelude.
- (active, extern_crate_item_prelude, "1.31.0", Some(55599), None),
-
  // `reason = ` in lint attributes and `expect` lint attribute
  (active, lint_reasons, "1.31.0", Some(54503), None),
 );
@@ -691,6 +688,8 @@ declare_features! (
  // impl<I:Iterator> Iterator for &mut Iterator
  // impl Debug for Foo<'_>
  (accepted, impl_header_lifetime_elision, "1.31.0", Some(15872), None),
+ // `extern crate foo as bar;` puts `bar` into extern prelude.
+ (accepted, extern_crate_item_prelude, "1.31.0", Some(55599), None),
 );
 
 // If you change this, please modify src/doc/unstable-book as well. You must

src/test/ui-fulldeps/proc-macro/extern-prelude-extern-crate-proc-macro.rs

@@ -1,8 +1,6 @@
 // compile-pass
 // edition:2018
 
-#![feature(extern_crate_item_prelude)]
-
 extern crate proc_macro;
 use proc_macro::TokenStream; // OK
 

src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.rs

@@ -1,8 +1,6 @@
 // compile-pass
 // edition:2018
 
-#![feature(extern_crate_item_prelude)]
-
 macro_rules! define_iso { () => {
  extern crate std as iso;
 }}

src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.stderr

@@ -1,7 +1,6 @@
 // compile-pass
 // compile-flags:--cfg my_feature
 
-#![feature(extern_crate_item_prelude)]
 #![no_std]
 
 #[cfg(my_feature)]

src/test/ui/imports/extern-prelude-extern-crate-absolute-expanded.rs

@@ -1,8 +1,6 @@
 // compile-pass
 // aux-build:two_macros.rs
 
-#![feature(extern_crate_item_prelude)]
-
 extern crate two_macros;
 
 mod m {