error[E0015]: cannot call non-const fn `<Dim3 as Dim>::dim` in constants
  --> $DIR/issue-39559-2.rs:14:24
   |
LL |     let array: [usize; Dim3::dim()]
   |                        ^^^^^^^^^^^
   |
   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable

error[E0015]: cannot call non-const fn `<Dim3 as Dim>::dim` in constants
  --> $DIR/issue-39559-2.rs:16:15
   |
LL |         = [0; Dim3::dim()];
   |               ^^^^^^^^^^^
   |
   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0015`.