error[E0308]: mismatched types --> $DIR/issue-39974.rs:5:19 | LL | f: [[f64; 2]; LENGTH], | ^^^^^^ expected `usize`, found `f64` error[E0308]: mismatched types --> $DIR/issue-39974.rs:1:21 | LL | const LENGTH: f64 = 2; | ^ | | | expected `f64`, found integer | help: use a float literal: `2.0` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0308`.