diff --git a/src/test/ui/const-eval/match-test-ptr-null.rs b/src/test/ui/const-eval/match-test-ptr-null.rs
index 19b3dcc3181..81fcd23fb78 100644
--- a/src/test/ui/const-eval/match-test-ptr-null.rs
+++ b/src/test/ui/const-eval/match-test-ptr-null.rs
@@ -13,7 +13,7 @@ fn main() {
     // that pointer comparison is disallowed, not that parts of a pointer are accessed as raw
     // bytes.
     let _: [u8; 0] = [4; { //~ ERROR could not evaluate repeat length
-        match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
+        match &1 as *const i32 as usize { //~ ERROR casting pointers to integers in constants
             0 => 42, //~ ERROR constant contains unimplemented expression type
             //~^ NOTE "pointer arithmetic or comparison" needs an rfc before being allowed
             n => n,
diff --git a/src/test/ui/const-eval/match-test-ptr-null.stderr b/src/test/ui/const-eval/match-test-ptr-null.stderr
index 726ada9b428..26577948fae 100644
--- a/src/test/ui/const-eval/match-test-ptr-null.stderr
+++ b/src/test/ui/const-eval/match-test-ptr-null.stderr
@@ -1,8 +1,10 @@
-error[E0018]: raw pointers cannot be cast to integers in constants
+error[E0658]: casting pointers to integers in constants is unstable (see issue #51910)
   --> $DIR/match-test-ptr-null.rs:16:15
    |
-LL |         match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
+LL |         match &1 as *const i32 as usize { //~ ERROR casting pointers to integers in constants
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
 error[E0019]: constant contains unimplemented expression type
   --> $DIR/match-test-ptr-null.rs:17:13
@@ -15,7 +17,7 @@ error[E0080]: could not evaluate repeat length
    |
 LL |       let _: [u8; 0] = [4; { //~ ERROR could not evaluate repeat length
    |  __________________________^
-LL | |         match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
+LL | |         match &1 as *const i32 as usize { //~ ERROR casting pointers to integers in constants
 LL | |             0 => 42, //~ ERROR constant contains unimplemented expression type
    | |             - "pointer arithmetic or comparison" needs an rfc before being allowed inside constants
 LL | |             //~^ NOTE "pointer arithmetic or comparison" needs an rfc before being allowed
@@ -26,5 +28,5 @@ LL | |     }];
 
 error: aborting due to 3 previous errors
 
-Some errors occurred: E0018, E0019, E0080.
-For more information about an error, try `rustc --explain E0018`.
+Some errors occurred: E0019, E0080, E0658.
+For more information about an error, try `rustc --explain E0019`.
diff --git a/src/test/ui/issue-17458.stderr b/src/test/ui/issue-17458.stderr
index 7a43813fa6d..0303e4bddb5 100644
--- a/src/test/ui/issue-17458.stderr
+++ b/src/test/ui/issue-17458.stderr
@@ -1,9 +1,11 @@
-error[E0018]: raw pointers cannot be cast to integers in statics
+error[E0658]: casting pointers to integers in statics is unstable (see issue #51910)
   --> $DIR/issue-17458.rs:11:19
    |
 LL | static X: usize = 0 as *const usize as usize;
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0018`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/issue-18294.stderr b/src/test/ui/issue-18294.stderr
index 151deefb2b7..0b94e778d37 100644
--- a/src/test/ui/issue-18294.stderr
+++ b/src/test/ui/issue-18294.stderr
@@ -1,9 +1,11 @@
-error[E0018]: raw pointers cannot be cast to integers in constants
+error[E0658]: casting pointers to integers in constants is unstable (see issue #51910)
   --> $DIR/issue-18294.rs:13:22
    |
-LL |     const Y: usize = &X as *const u32 as usize; //~ ERROR E0018
+LL |     const Y: usize = &X as *const u32 as usize; //~ ERROR is unstable
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0018`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/issue-52023-array-size-pointer-cast.rs b/src/test/ui/issue-52023-array-size-pointer-cast.rs
index f3bee1a6315..02bed69f0d4 100644
--- a/src/test/ui/issue-52023-array-size-pointer-cast.rs
+++ b/src/test/ui/issue-52023-array-size-pointer-cast.rs
@@ -9,5 +9,5 @@
 // except according to those terms.
 
 fn main() {
-    let _ = [0; (&0 as *const i32) as usize]; //~ ERROR raw pointers cannot be cast
+    let _ = [0; (&0 as *const i32) as usize]; //~ ERROR casting pointers to integers in constants
 }
diff --git a/src/test/ui/issue-52023-array-size-pointer-cast.stderr b/src/test/ui/issue-52023-array-size-pointer-cast.stderr
index 888de82e379..74270c2bef7 100644
--- a/src/test/ui/issue-52023-array-size-pointer-cast.stderr
+++ b/src/test/ui/issue-52023-array-size-pointer-cast.stderr
@@ -1,9 +1,11 @@
-error[E0018]: raw pointers cannot be cast to integers in constants
+error[E0658]: casting pointers to integers in constants is unstable (see issue #51910)
   --> $DIR/issue-52023-array-size-pointer-cast.rs:12:17
    |
-LL |     let _ = [0; (&0 as *const i32) as usize]; //~ ERROR raw pointers cannot be cast
+LL |     let _ = [0; (&0 as *const i32) as usize]; //~ ERROR casting pointers to integers in constants
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0018`.
+For more information about this error, try `rustc --explain E0658`.