error[E0119]: conflicting implementations of trait `From<(_,)>` for type `(_,)` --> $DIR/coherence-overlap-all-t-and-tuple.rs:16:1 | LL | impl From for T { | ---------------------- first implementation here ... LL | impl From<(U11,)> for (T11,) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `(_,)` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0119`.