stabilize extern_crate_self

Author: mehcode

Diff for: src/librustc_resolve/build_reduced_graph.rs

@@ -30,7 +30,7 @@ use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::base::Determinacy::Undetermined;
 use syntax::ext::hygiene::Mark;
 use syntax::ext::tt::macro_rules;
-use syntax::feature_gate::{is_builtin_attr, emit_feature_err, GateIssue};
+use syntax::feature_gate::is_builtin_attr;
 use syntax::parse::token::{self, Token};
 use syntax::std_inject::injected_crate_name;
 use syntax::symbol::keywords;
@@ -349,10 +349,6 @@ impl<'a> Resolver<'a> {
                         .emit();
                     return;
                 } else if orig_name == Some(keywords::SelfLower.name()) {
-                    if !self.session.features_untracked().extern_crate_self {
-                        emit_feature_err(&self.session.parse_sess, "extern_crate_self", item.span,
-                                         GateIssue::Language, "`extern crate self` is unstable");
-                    }
                     self.graph_root
                 } else {
                     let crate_id = self.crate_loader.process_extern_crate(item, &self.definitions);

Diff for: src/libsyntax/feature_gate.rs

@@ -453,9 +453,6 @@ declare_features! (
     // Adds `reason` and `expect` lint attributes.
     (active, lint_reasons, "1.31.0", Some(54503), None),
 
-    // `extern crate self as foo;` puts local crate root into extern prelude under name `foo`.
-    (active, extern_crate_self, "1.31.0", Some(56409), None),
-
     // Allows paths to enum variants on type aliases.
     (active, type_alias_enum_variants, "1.31.0", Some(49683), None),
 
@@ -685,6 +682,8 @@ declare_features! (
     (accepted, uniform_paths, "1.32.0", Some(53130), None),
     // Allows `cfg(target_vendor = "...")`.
     (accepted, cfg_target_vendor, "1.33.0", Some(29718), None),
+    // `extern crate self as foo;` puts local crate root into extern prelude under name `foo`.
+    (accepted, extern_crate_self, "1.34.0", Some(56409), None),
 );
 
 // If you change this, please modify `src/doc/unstable-book` as well. You must

Diff for: src/test/ui/feature-gates/feature-gate-extern_crate_self.rs

@@ -1,5 +1,3 @@
-#![feature(extern_crate_self)]
-
 extern crate self; //~ ERROR `extern crate self;` requires renaming
 
 #[macro_use] //~ ERROR `macro_use` is not supported on `extern crate self`

Diff for: src/test/ui/feature-gates/feature-gate-extern_crate_self.stderr

@@ -1,11 +1,11 @@
 error: `extern crate self;` requires renaming
-  --> $DIR/extern-crate-self-fail.rs:3:1
+  --> $DIR/extern-crate-self-fail.rs:1:1
    |
 LL | extern crate self; //~ ERROR `extern crate self;` requires renaming
    | ^^^^^^^^^^^^^^^^^^ help: try: `extern crate self as name;`
 
 error: `macro_use` is not supported on `extern crate self`
-  --> $DIR/extern-crate-self-fail.rs:5:1
+  --> $DIR/extern-crate-self-fail.rs:3:1
    |
 LL | #[macro_use] //~ ERROR `macro_use` is not supported on `extern crate self`
    | ^^^^^^^^^^^^

Diff for: src/test/ui/imports/extern-crate-self-fail.rs renamed to src/test/ui/imports/extern-crate-self/extern-crate-self-fail.rs

@@ -0,0 +1,16 @@
+// run-pass
+
+// Test that a macro can correctly expand the alias
+// in an `extern crate self as ALIAS` item.
+
+fn the_answer() -> usize { 42 }
+
+macro_rules! alias_self {
+    ($alias:ident) => { extern crate self as $alias; }
+}
+
+alias_self!(the_alias);
+
+fn main() {
+    assert_eq!(the_alias::the_answer(), 42);
+}

Diff for: src/test/ui/imports/extern-crate-self-fail.stderr renamed to src/test/ui/imports/extern-crate-self/extern-crate-self-fail.stderr

@@ -0,0 +1,12 @@
+// compile-pass
+
+// Test that `extern crate self;` is accepted
+// syntactically as an item for use in a macro.
+
+macro_rules! accept_item { ($x:item) => {} }
+
+accept_item! {
+    extern crate self;
+}
+
+fn main() {}

Diff for: src/test/ui/imports/extern-crate-self/extern-crate-self-macro-alias.rs

@@ -0,0 +1,16 @@
+// run-pass
+
+// Test that a macro can correctly expand `self` in
+// an `extern crate self as ALIAS` item.
+
+fn the_answer() -> usize { 42 }
+
+macro_rules! extern_something {
+    ($alias:ident) => { extern crate $alias as the_alias; }
+}
+
+extern_something!(self);
+
+fn main() {
+    assert_eq!(the_alias::the_answer(), 42);
+}

Diff for: src/test/ui/imports/extern-crate-self/extern-crate-self-macro-item.rs

@@ -1,7 +1,5 @@
 // compile-pass
 
-#![feature(extern_crate_self)]
-
 extern crate self as foo;
 
 struct S;