error[E0119]: conflicting implementations of trait `MyTrait` for type `lib::MyFundamentalStruct<(MyType,)>` --> $DIR/coherence_copy_like_err_fundamental_struct_tuple.rs:16:1 | LL | impl MyTrait for T { } | ---------------------------------- first implementation here ... LL | impl MyTrait for lib::MyFundamentalStruct<(MyType,)> { } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `lib::MyFundamentalStruct<(MyType,)>` | = note: upstream crates may add a new impl of trait `lib::MyCopy` for type `lib::MyFundamentalStruct<(MyType,)>` in future versions error: aborting due to previous error For more information about this error, try `rustc --explain E0119`.