error[E0277]: the size for values of type `<T as Get>::Value` cannot be known at compilation time
  --> $DIR/associated-types-unsized.rs:10:9
   |
LL |     let x = t.get();
   |         ^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `<T as Get>::Value`
   = note: all local variables must have a statically known size
   = help: unsized locals are gated as an unstable feature
help: consider further restricting the associated type
   |
LL | fn foo<T:Get>(t: T) where <T as Get>::Value: Sized {
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.