rustc: Obsolete the `@` syntax entirely

This removes all remnants of `@` pointers from rustc. Additionally, this removes
the `GC` structure from the prelude as it seems odd exporting an experimental
type in the prelude by default.

Closes #14193
[breaking-change]

1 files changed, 4 insertions, 2 deletions

diff --git a/src/test/debuginfo/managed-pointer-within-unique.rs b/src/test/debuginfo/managed-pointer-within-unique.rs
index be2cc696d4f..b56db2d1846 100644
--- a/src/test/debuginfo/managed-pointer-within-unique.rs
+++ b/src/test/debuginfo/managed-pointer-within-unique.rs
@@ -29,15 +29,17 @@
 
 #![allow(unused_variable)]
 
+use std::gc::{GC, Gc};
+
 struct ContainsManaged {
     x: int,
-    y: @int
+    y: Gc<int>,
 }
 
 fn main() {
     let ordinary_unique = box() (-1, -2);
 
-    let managed_within_unique = box ContainsManaged { x: -3, y: @-4 };
+    let managed_within_unique = box ContainsManaged { x: -3, y: box(GC) -4 };
 
     zzz();
 }