error: const `impl` for trait `Default` which is not marked with `#[const_trait]` --> $DIR/rustc-impl-const-stability.rs:15:12 | LL | impl const Default for Data { | ^^^^^^^ | = note: marking a trait with `#[const_trait]` ensures all default method bodies are `const` = note: adding a non-const method body in the future would be a breaking change error: aborting due to previous error