Rollup merge of rust-lang#53236 - alexreg:stabilise-raw-idents, r=cramertj

Stabilise raw_identifiers feature

* [Reference PR](rust-lang/reference#395)
* [Book PR](rust-lang/book#1480)
* [Rust by Example PR](rust-lang/rust-by-example#1095)

Closes rust-lang#48589.

r? @cramertj
CC @cuviper @Centril

Author: kennytm

src/librustc_lint/builtin.rs

@@ -1927,14 +1927,12 @@ impl Async2018 {
         );
 
         // Don't suggest about raw identifiers if the feature isn't active
-        if cx.sess.features_untracked().raw_identifiers {
-            lint.span_suggestion_with_applicability(
-                span,
-                "you can use a raw identifier to stay compatible",
-                "r#async".to_string(),
-                Applicability::MachineApplicable,
-            );
-        }
+        lint.span_suggestion_with_applicability(
+            span,
+            "you can use a raw identifier to stay compatible",
+            "r#async".to_string(),
+            Applicability::MachineApplicable,
+        );
         lint.emit()
     }
 }

src/libsyntax/diagnostic_list.rs

@@ -382,8 +382,9 @@ Erroneous code example:
 
 ```ignore (limited to a warning during 2018 edition development)
 #![feature(rust_2018_preview)]
-#![feature(raw_identifiers)] // error: the feature `raw_identifiers` is
-                             // included in the Rust 2018 edition
+#![feature(impl_header_lifetime_elision)] // error: the feature
+                                          // `impl_header_lifetime_elision` is
+                                          // included in the Rust 2018 edition
 ```
 
 "##,

src/libsyntax/feature_gate.rs

@@ -433,9 +433,6 @@ declare_features! (
     // `use path as _;` and `extern crate c as _;`
     (active, underscore_imports, "1.26.0", Some(48216), None),
 
-    // Allows keywords to be escaped for use as identifiers
-    (active, raw_identifiers, "1.26.0", Some(48589), Some(Edition::Edition2018)),
-
     // Allows macro invocations in `extern {}` blocks
     (active, macros_in_extern, "1.27.0", Some(49476), None),
 
@@ -646,6 +643,8 @@ declare_features! (
     (accepted, repr_transparent, "1.28.0", Some(43036), None),
     // Defining procedural macros in `proc-macro` crates
     (accepted, proc_macro, "1.29.0", Some(38356), None),
+    // Allows keywords to be escaped for use as identifiers
+    (accepted, raw_identifiers, "1.30.0", Some(48589), None),
 );
 
 // If you change this, please modify src/doc/unstable-book as well. You must
@@ -2021,16 +2020,6 @@ pub fn check_crate(krate: &ast::Crate,
         plugin_attributes,
     };
 
-    if !features.raw_identifiers {
-        for &span in sess.raw_identifier_spans.borrow().iter() {
-            if !span.allows_unstable() {
-                gate_feature!(&ctx, raw_identifiers, span,
-                    "raw identifiers are experimental and subject to change"
-                );
-            }
-        }
-    }
-
     let visitor = &mut PostExpansionVisitor { context: &ctx };
     visitor.whole_crate_feature_gates(krate);
     visit::walk_crate(visitor, krate);

src/test/run-pass/auxiliary/edition-kw-macro-2015.rs

@@ -10,8 +10,6 @@
 
 // edition:2015
 
-#![feature(raw_identifiers)]
-
 #[macro_export]
 macro_rules! produces_async {
     () => (pub fn async() {})

src/test/run-pass/edition-keywords-2015-2015.rs

@@ -11,8 +11,6 @@
 // edition:2015
 // aux-build:edition-kw-macro-2015.rs
 
-#![feature(raw_identifiers)]
-
 #[macro_use]
 extern crate edition_kw_macro_2015;
 

src/test/run-pass/edition-keywords-2015-2018.rs

@@ -11,8 +11,6 @@
 // edition:2015
 // aux-build:edition-kw-macro-2018.rs
 
-#![feature(raw_identifiers)]
-
 #[macro_use]
 extern crate edition_kw_macro_2018;
 

src/test/run-pass/rfc-2151-raw-identifiers/attr.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(raw_identifiers)]
-
 use std::mem;
 
 #[r#repr(r#C, r#packed)]

src/test/run-pass/rfc-2151-raw-identifiers/basic.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(raw_identifiers)]
-
 fn r#fn(r#match: u32) -> u32 {
     r#match
 }

src/test/run-pass/rfc-2151-raw-identifiers/items.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(raw_identifiers)]
-
 #[derive(Debug, PartialEq, Eq)]
 struct IntWrapper(u32);
 

src/test/run-pass/rfc-2151-raw-identifiers/macros.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![feature(decl_macro)]
-#![feature(raw_identifiers)]
 
 r#macro_rules! r#struct {
     ($r#struct:expr) => { $r#struct }