tests/ui/union/union-const-pat.stderr

error: cannot use unions in constant patterns
  --> $DIR/union-const-pat.rs:10:9
   |
LL | const C: U = U { a: 10 };
   | ---------- constant defined here
...
LL |         C => {}
   |         ^ can't use a `union` here

error: aborting due to 1 previous error