error[E0381]: borrow of possibly-uninitialized variable: `x`
  --> $DIR/issue-78655.rs:3:5
   |
LL |     &x
   |     ^^ use of possibly-uninitialized `x`

error: encountered dangling pointer in final constant
  --> $DIR/issue-78655.rs:1:1
   |
LL | / const FOO: *const u32 = {
LL | |     let x;
LL | |     &x
LL | | };
   | |__^

error: could not evaluate constant pattern
  --> $DIR/issue-78655.rs:7:9
   |
LL |     let FOO = FOO;
   |         ^^^

error: could not evaluate constant pattern
  --> $DIR/issue-78655.rs:7:9
   |
LL |     let FOO = FOO;
   |         ^^^

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0381`.