Remove the const_raw_ptr_comparison feature gate.

We can never supply a meaningful implementation of this.
Instead, the follow up commits will create two intrinsics
that approximate comparisons:

* `ptr_maybe_eq`
* `ptr_maybe_ne`

The fact that `ptr_maybe_eq(a, b)` is not necessarily the same
value as `!ptr_maybe_ne(a, b)` is a symptom of this entire
problem.

2 files changed, 5 insertions, 8 deletions

diff --git a/src/test/ui/error-codes/E0395.rs b/src/test/ui/error-codes/E0395.rs
index bbefff27d7f..28fba1d3061 100644
--- a/src/test/ui/error-codes/E0395.rs
+++ b/src/test/ui/error-codes/E0395.rs
@@ -1,10 +1,8 @@
-// gate-test-const_compare_raw_pointers
-
 static FOO: i32 = 42;
 static BAR: i32 = 42;
 
 static BAZ: bool = unsafe { (&FOO as *const i32) == (&BAR as *const i32) };
-//~^ ERROR comparing raw pointers inside static
+//~^ ERROR pointers cannot be compared in a meaningful way during const eval
 
 fn main() {
 }
diff --git a/src/test/ui/error-codes/E0395.stderr b/src/test/ui/error-codes/E0395.stderr
index 20c8622f337..748126f7440 100644
--- a/src/test/ui/error-codes/E0395.stderr
+++ b/src/test/ui/error-codes/E0395.stderr
@@ -1,12 +1,11 @@
-error[E0658]: comparing raw pointers inside static
-  --> $DIR/E0395.rs:6:29
+error: pointers cannot be compared in a meaningful way during const eval.
+  --> $DIR/E0395.rs:4:29
    |
 LL | static BAZ: bool = unsafe { (&FOO as *const i32) == (&BAR as *const i32) };
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #53020 <https://github.com/rust-lang/rust/issues/53020> for more information
-   = help: add `#![feature(const_compare_raw_pointers)]` to the crate attributes to enable
+   = note: It is conceptually impossible for const eval to know in all cases whether two pointers are equal. While sometimes it is clear (the address of a static item is never equal to the address of another static item), comparing an integer address with any allocation's address is impossible to do at compile-time.
+   = note: That said, there's the `ptr_maybe_eq` intrinsic which returns `true` for all comparisons where CTFE isn't sure whether two addresses are equal. The mirror intrinsic `ptr_maybe_ne` returns `true` for all comparisons where CTFE isn't sure whether two addresses are inequal.
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.