error: the `function` method cannot be invoked on a trait object
  --> $DIR/mutability-mismatch.rs:28:33
   |
LL |         Self: Sized;
   |               ----- this has a `Sized` requirement
...
LL |     (&MutType as &dyn MutTrait).function();
   |                                 ^^^^^^^^
   |
   = note: you need `&mut dyn MutTrait` instead of `&dyn MutTrait`

error: the `function` method cannot be invoked on a trait object
  --> $DIR/mutability-mismatch.rs:31:35
   |
LL |         Self: Sized;
   |               ----- this has a `Sized` requirement
...
LL |     (&mut Type as &mut dyn Trait).function();
   |                                   ^^^^^^^^
   |
   = note: you need `&dyn Trait` instead of `&mut dyn Trait`

error: aborting due to 2 previous errors