error[E0309]: the associated type `<Self as SomeTrait<'a>>::Type1` may not live long enough
  --> $DIR/wf-trait-associated-type-region.rs:9:18
   |
LL |     type Type2 = &'a Self::Type1;
   |                  ^^^^^^^^^^^^^^^
   |
   = help: consider adding an explicit lifetime bound `<Self as SomeTrait<'a>>::Type1: 'a`...
   = note: ...so that the reference type `&'a <Self as SomeTrait<'a>>::Type1` does not outlive the data it points at

error: aborting due to previous error

For more information about this error, try `rustc --explain E0309`.