error[E0277]: the trait bound `[Adt; std::mem::size_of::()]: Foo` is not satisfied --> $DIR/dont-evaluate-array-len-on-err-1.rs:15:10 | LL | <[Adt; std::mem::size_of::()] as Foo>::bar() | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `[Adt; std::mem::size_of::()]` | help: this trait has no implementations, consider adding one --> $DIR/dont-evaluate-array-len-on-err-1.rs:9:1 | LL | trait Foo { | ^^^^^^^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.