error[E0308]: mismatched types --> $DIR/const-tup-index-span.rs:3:23 | LL | const TUP: (usize,) = 5usize << 64; | ^^^^^^^^^^^^ expected tuple, found `usize` | = note: expected tuple `(usize,)` found type `usize` help: use a trailing comma to create a tuple with one element | LL | const TUP: (usize,) = (5usize << 64,); | + ++ note: erroneous constant used --> $DIR/const-tup-index-span.rs:6:18 | LL | const ARR: [i32; TUP.0] = []; | ^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.