error[E0379]: functions in traits cannot be declared const --> $DIR/issue-54954.rs:5:5 | LL | const fn const_val() -> usize { | ^^^^^ functions in traits cannot be const error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type --> $DIR/issue-54954.rs:1:24 | LL | const ARR_LEN: usize = Tt::const_val::<[i8; 123]>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot call associated function of trait ... LL | / const fn const_val() -> usize { LL | | LL | | core::mem::size_of::() LL | | } | |_____- `Tt::const_val` defined here error[E0080]: evaluation of constant value failed --> $DIR/issue-54954.rs:11:15 | LL | fn f(z: [f32; ARR_LEN]) -> [f32; ARR_LEN] { | ^^^^^^^ referenced constant has errors error[E0080]: evaluation of constant value failed --> $DIR/issue-54954.rs:11:34 | LL | fn f(z: [f32; ARR_LEN]) -> [f32; ARR_LEN] { | ^^^^^^^ referenced constant has errors error: aborting due to 4 previous errors Some errors have detailed explanations: E0080, E0379, E0790. For more information about an error, try `rustc --explain E0080`.