error[E0119]: conflicting implementations of trait `Sweet` for type `std::boxed::Box<_>` --> $DIR/coherence-overlap-issue-23516.rs:8:1 | LL | impl Sweet for T { } | ------------------------- first implementation here LL | impl Sweet for Box { } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `std::boxed::Box<_>` | = note: downstream crates may implement trait `Sugar` for type `std::boxed::Box<_>` error: aborting due to previous error For more information about this error, try `rustc --explain E0119`.