1 error[E0015]: cannot call non-const fn `<staged_api::Unstable as staged_api::MyTrait>::func` in constant functions
2 --> $DIR/staged-api-user-crate.rs:12:5
7 = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0015`.