error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
  --> $DIR/issue-20831-debruijn.rs:38:5
   |
LL | /     fn subscribe(&mut self, t : Box<Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
LL | |         // Not obvious, but there is an implicit lifetime here -------^
LL | |         //~^^ ERROR cannot infer
LL | |         //
...  |
LL | |         self.sub = t;
LL | |     }
   | |_____^
   |
note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the method body at 38:5...
  --> $DIR/issue-20831-debruijn.rs:38:5
   |
LL | /     fn subscribe(&mut self, t : Box<Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
LL | |         // Not obvious, but there is an implicit lifetime here -------^
LL | |         //~^^ ERROR cannot infer
LL | |         //
...  |
LL | |         self.sub = t;
LL | |     }
   | |_____^
note: ...but the lifetime must also be valid for the lifetime 'a as defined on the impl at 36:6...
  --> $DIR/issue-20831-debruijn.rs:36:6
   |
LL | impl<'a> Publisher<'a> for MyStruct<'a> {
   |      ^^
   = note: ...so that the types are compatible:
           expected Publisher<'_>
              found Publisher<'_>

error: aborting due to previous error

For more information about this error, try `rustc --explain E0495`.