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

Stabilize `extern_crate_item_prelude`

Closes https://github.com/rust-lang/rust/issues/55599

9 files changed, 33 insertions, 133 deletions

diff --git a/src/test/ui-fulldeps/proc-macro/extern-prelude-extern-crate-proc-macro.rs b/src/test/ui-fulldeps/proc-macro/extern-prelude-extern-crate-proc-macro.rs
index e320ad97135..25a2a376147 100644
--- a/src/test/ui-fulldeps/proc-macro/extern-prelude-extern-crate-proc-macro.rs
+++ b/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
 
diff --git a/src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.rs b/src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.rs
deleted file mode 100644
index 27b9a34ff4e..00000000000
--- a/src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.rs
+++ /dev/null
@@ -1,46 +0,0 @@
-// edition:2018
-
-#![feature(alloc, underscore_imports)]
-
-extern crate alloc;
-
-mod in_scope {
-    fn check() {
-        let v = alloc::vec![0];
-        //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-        type A = alloc::boxed::Box<u8>;
-        //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-    }
-}
-
-mod absolute {
-    fn check() {
-        let v = ::alloc::vec![0];
-        //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-        type A = ::alloc::boxed::Box<u8>;
-        //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-    }
-}
-
-mod import_in_scope {
-    use alloc as _;
-    //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-    use alloc::boxed;
-    //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-}
-
-mod import_absolute {
-    use ::alloc;
-    //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-    use ::alloc::boxed;
-    //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-}
-
-extern crate alloc as core;
-
-mod unrelated_crate_renamed {
-    type A = core::boxed::Box<u8>;
-    //~^ ERROR use of extern prelude names introduced with `extern crate` items is unstable
-}
-
-fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.stderr b/src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.stderr
deleted file mode 100644
index 103ab79ef84..00000000000
--- a/src/test/ui/feature-gates/feature-gate-extern_crate_item_prelude.stderr
+++ /dev/null
@@ -1,75 +0,0 @@
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:26:9
-   |
-LL |     use alloc as _;
-   |         ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:28:9
-   |
-LL |     use alloc::boxed;
-   |         ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:33:11
-   |
-LL |     use ::alloc;
-   |           ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:35:11
-   |
-LL |     use ::alloc::boxed;
-   |           ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:9:17
-   |
-LL |         let v = alloc::vec![0];
-   |                 ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:11:18
-   |
-LL |         type A = alloc::boxed::Box<u8>;
-   |                  ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:18:19
-   |
-LL |         let v = ::alloc::vec![0];
-   |                   ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:20:20
-   |
-LL |         type A = ::alloc::boxed::Box<u8>;
-   |                    ^^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error[E0658]: use of extern prelude names introduced with `extern crate` items is unstable (see issue #55599)
-  --> $DIR/feature-gate-extern_crate_item_prelude.rs:42:14
-   |
-LL |     type A = core::boxed::Box<u8>;
-   |              ^^^^
-   |
-   = help: add #![feature(extern_crate_item_prelude)] to the crate attributes to enable
-
-error: aborting due to 9 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/imports/extern-prelude-extern-crate-absolute-expanded.rs b/src/test/ui/imports/extern-prelude-extern-crate-absolute-expanded.rs
index b1154f2076b..cf91a9714ad 100644
--- a/src/test/ui/imports/extern-prelude-extern-crate-absolute-expanded.rs
+++ b/src/test/ui/imports/extern-prelude-extern-crate-absolute-expanded.rs
@@ -1,8 +1,6 @@
 // compile-pass
 // edition:2018
 
-#![feature(extern_crate_item_prelude)]
-
 macro_rules! define_iso { () => {
     extern crate std as iso;
 }}
diff --git a/src/test/ui/imports/extern-prelude-extern-crate-cfg.rs b/src/test/ui/imports/extern-prelude-extern-crate-cfg.rs
index c48a65798b6..6117e5f6f3c 100644
--- a/src/test/ui/imports/extern-prelude-extern-crate-cfg.rs
+++ b/src/test/ui/imports/extern-prelude-extern-crate-cfg.rs
@@ -1,7 +1,6 @@
 // compile-pass
 // compile-flags:--cfg my_feature
 
-#![feature(extern_crate_item_prelude)]
 #![no_std]
 
 #[cfg(my_feature)]
diff --git a/src/test/ui/imports/extern-prelude-extern-crate-pass.rs b/src/test/ui/imports/extern-prelude-extern-crate-pass.rs
index 8c147dfd04a..bb4cf6ca99c 100644
--- a/src/test/ui/imports/extern-prelude-extern-crate-pass.rs
+++ b/src/test/ui/imports/extern-prelude-extern-crate-pass.rs
@@ -1,8 +1,6 @@
 // compile-pass
 // aux-build:two_macros.rs
 
-#![feature(extern_crate_item_prelude)]
-
 extern crate two_macros;
 
 mod m {
diff --git a/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.rs b/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.rs
index 732f1c4de2f..6ff3ab73639 100644
--- a/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.rs
+++ b/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.rs
@@ -1,7 +1,5 @@
 // aux-build:two_macros.rs
 
-#![feature(extern_crate_item_prelude)]
-
 macro_rules! define_vec {
     () => {
         extern crate std as Vec;
@@ -16,4 +14,13 @@ mod m {
     }
 }
 
+macro_rules! define_other_core {
+    () => {
+        extern crate std as core;
+        //~^ ERROR macro-expanded `extern crate` items cannot shadow names passed with `--extern`
+    }
+}
+
+define_other_core!();
+
 fn main() {}
diff --git a/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.stderr b/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.stderr
index 218dfb796f7..795e1761ccd 100644
--- a/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.stderr
+++ b/src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.stderr
@@ -1,12 +1,21 @@
+error: macro-expanded `extern crate` items cannot shadow names passed with `--extern`
+  --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:19:9
+   |
+LL |         extern crate std as core;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | define_other_core!();
+   | --------------------- in this macro invocation
+
 error[E0659]: `Vec` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
-  --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:15:9
+  --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:13:9
    |
 LL |         Vec::panic!(); //~ ERROR `Vec` is ambiguous
    |         ^^^ ambiguous name
    |
    = note: `Vec` could refer to a struct from prelude
 note: `Vec` could also refer to the extern crate imported here
-  --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:7:9
+  --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:5:9
    |
 LL |         extern crate std as Vec;
    |         ^^^^^^^^^^^^^^^^^^^^^^^^
@@ -14,6 +23,6 @@ LL |         extern crate std as Vec;
 LL | define_vec!();
    | -------------- in this macro invocation
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0659`.
diff --git a/src/test/ui/imports/extern-prelude-extern-crate-shadowing.rs b/src/test/ui/imports/extern-prelude-extern-crate-shadowing.rs
new file mode 100644
index 00000000000..c5adeaf17fa
--- /dev/null
+++ b/src/test/ui/imports/extern-prelude-extern-crate-shadowing.rs
@@ -0,0 +1,12 @@
+// compile-pass
+// aux-build:two_macros.rs
+
+extern crate two_macros as core;
+
+mod m {
+    fn check() {
+        core::m!(); // OK
+    }
+}
+
+fn main() {}