error[E0106]: missing lifetime specifier
  --> $DIR/unboxed-closure-sugar-lifetime-elision.rs:26:39
   |
LL |     let _: dyn Foo(&isize, &usize) -> &usize;
   |                    ------  ------     ^ expected named lifetime parameter
   |
   = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
help: consider introducing a named lifetime parameter
   |
LL ~ fn main<'a>() {
LL |     eq::< dyn for<'a> Foo<(&'a isize,), Output=&'a isize>,
LL |           dyn Foo(&isize) -> &isize                                   >();
LL |     eq::< dyn for<'a> Foo<(&'a isize,), Output=(&'a isize, &'a isize)>,
LL |           dyn Foo(&isize) -> (&isize, &isize)                           >();
LL | 
 ...

error: aborting due to previous error

For more information about this error, try `rustc --explain E0106`.