LL | let Helper::U(u) = Helper::T(t, []);
| ^^^^^^^^^^^^ pattern `T(_, _)` not covered
+warning[E0381]: use of possibly uninitialized variable: `u`
+ --> $DIR/empty-never-array.rs:12:5
+ |
+LL | u
+ | ^ use of possibly uninitialized `u`
+ |
+ = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+ = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+ = note: for more information, try `rustc --explain E0729`
+
error: aborting due to previous error
-For more information about this error, try `rustc --explain E0005`.
+Some errors have detailed explanations: E0005, E0381.
+For more information about an error, try `rustc --explain E0005`.