error[E0019]: constant contains unimplemented expression type
  --> $DIR/const-if.rs:1:20
   |
LL | const _X: i32 = if true { 5 } else { 6 };
   |                    ^^^^

error[E0019]: constant contains unimplemented expression type
  --> $DIR/const-if.rs:1:17
   |
LL | const _X: i32 = if true { 5 } else { 6 };
   |                 ^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0019`.