stabilize #[doc_alias = "..."]

src/doc/rustdoc/src/the-doc-attribute.md

@@ -214,3 +214,17 @@ the `strip-hidden` pass is removed.
 Since primitive types are defined in the compiler, there's no place to attach documentation
 attributes. This attribute is used by the standard library to provide a way to generate
 documentation for primitive types.
+
+## `#[doc(alias)]`: Add aliases for an item in documentation search
+
+This feature allows you to add alias(es) to an item when using the `rustdoc` search through the
+`doc(alias)` attribute. Example:
+
+```rust,no_run
+#[doc(alias = "x")]
+#[doc(alias = "big")]
+pub struct BigX;
+```
+
+Then, when looking for it through the `rustdoc` search, if you enter "x" or
+"big", search will show the `BigX` struct first.

src/doc/rustdoc/src/unstable-features.md

@@ -195,22 +195,6 @@ issue][issue-include].
 [unstable-include]: ../unstable-book/language-features/external-doc.html
 [issue-include]: https://github.com/rust-lang/rust/issues/44732
 
-### Add aliases for an item in documentation search
-
-This feature allows you to add alias(es) to an item when using the `rustdoc` search through the
-`doc(alias)` attribute. Example:
-
-```rust,no_run
-#![feature(doc_alias)]
-
-#[doc(alias = "x")]
-#[doc(alias = "big")]
-pub struct BigX;
-```
-
-Then, when looking for it through the `rustdoc` search, if you enter "x" or
-"big", search will show the `BigX` struct first.
-
 ### Include items only when collecting doctests
 
 Rustdoc's [documentation tests] can do some things that regular unit tests can't, so it can

src/libcore/lib.rs

@@ -106,7 +106,6 @@
 #![feature(unsized_locals)]
 #![feature(untagged_unions)]
 #![feature(unwind_attributes)]
-#![feature(doc_alias)]
 #![feature(mmx_target_feature)]
 #![feature(tbm_target_feature)]
 #![feature(sse4a_target_feature)]

src/libstd/lib.rs

@@ -252,7 +252,6 @@
 #![feature(const_raw_ptr_deref)]
 #![feature(core_intrinsics)]
 #![feature(custom_test_frameworks)]
-#![feature(doc_alias)]
 #![feature(doc_cfg)]
 #![feature(doc_keyword)]
 #![feature(doc_masked)]

src/libsyntax/feature_gate.rs

@@ -450,9 +450,6 @@ declare_features! (
     // Allows comparing raw pointers during const eval.
     (active, const_compare_raw_pointers, "1.27.0", Some(53020), None),
 
-    // Allows `#[doc(alias = "...")]`.
-    (active, doc_alias, "1.27.0", Some(50146), None),
-
     // Allows inconsistent bounds in where clauses.
     (active, trivial_bounds, "1.28.0", Some(48214), None),
 
@@ -854,6 +851,8 @@ declare_features! (
     (accepted, repr_align_enum, "1.37.0", Some(57996), None),
     // Allows `const _: TYPE = VALUE`.
     (accepted, underscore_const_names, "1.37.0", Some(54912), None),
+    // Allows `#[doc(alias = "...")]`.
+    (accepted, doc_alias, "1.27.0", Some(50146), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features
@@ -1887,10 +1886,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                     gate_feature_post!(&self, doc_spotlight, attr.span,
                         "`#[doc(spotlight)]` is experimental"
                     );
-                } else if content.iter().any(|c| c.check_name(sym::alias)) {
-                    gate_feature_post!(&self, doc_alias, attr.span,
-                        "`#[doc(alias = \"...\")]` is experimental"
-                    );
                 } else if content.iter().any(|c| c.check_name(sym::keyword)) {
                     gate_feature_post!(&self, doc_keyword, attr.span,
                         "`#[doc(keyword = \"...\")]` is experimental"