error: implementation of `Foo` is not general enough
  --> $DIR/hrtb-conflate-regions.rs:27:10
   |
LL | / trait Foo<X> {
LL | |     fn foo(&self, x: X) { }
LL | | }
   | |_- trait `Foo` defined here
...
LL |   fn b() { want_foo2::<SomeStruct>(); }
   |            ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Foo` is not general enough
   |
   = note: `SomeStruct` must implement `Foo<(&'0 isize, &'1 isize)>`, for any two lifetimes `'0` and `'1`...
   = note: ...but `SomeStruct` actually implements `Foo<(&'2 isize, &'2 isize)>`, for some specific lifetime `'2`

error: aborting due to previous error