T: Sized
try_as_dyn
try_as_dyn_mut
`trait_info_of` already returns `None` for unsized types, so allowing `T: ?Sized` is sound and lets callers in generic contexts use these functions without a separate `Sized` bound. For unsized `T`, the function always returns `None`.
vtable_for
&T
&mut T
&dyn Trait