Adjust error message

src/test/ui/cenum_impl_drop_cast.rs

@@ -13,6 +13,6 @@ fn drop(&mut self) {
 fn main() {
     let e = E::A;
     let i = e as u32;
-    //~^ ERROR Cast `enum` implementing `Drop` `E` to integer `u32`
+    //~^ ERROR cannot cast enum `E` into integer `u32` because it implements `Drop`
     //~| WARN this was previously accepted
 }

src/test/ui/cenum_impl_drop_cast.stderr

@@ -1,4 +1,4 @@
-error: Cast `enum` implementing `Drop` `E` to integer `u32`
+error: cannot cast enum `E` into integer `u32` because it implements `Drop`
   --> $DIR/cenum_impl_drop_cast.rs:15:13
    |
 LL |     let i = e as u32;