while desugars to loop so 'a: while break 'a {} in ctfe doesn't work yet.

src/test/ui/consts/const-labeled-break.rs

@@ -4,7 +4,6 @@
 // See https://github.com/rust-lang/rust/issues/51350 for more information.
 
 const CRASH: () = 'a: while break 'a {};
+//~^ ERROR constant contains unimplemented expression type
 
-fn main() {
-    println!("{:?}", CRASH);
-}
+fn main() {}

src/test/ui/consts/const-labeled-break.stderr

@@ -0,0 +1,9 @@
+error[E0019]: constant contains unimplemented expression type
+  --> $DIR/const-labeled-break.rs:6:19
+   |
+LL | const CRASH: () = 'a: while break 'a {};
+   |                   ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0019`.