Cannot impl auto traits for free alias types that expand to otherwise legal self type

[fmease]

We just need to call expand_free_alias_tys on the self type in the relevant place in rustc_hir_analysis::coherence::orphan.

#![feature(lazy_type_alias)]

struct Local;
type Alias = Local;

unsafe impl Sync for Alias {} //~ ERROR cross-crate traits with a default impl, like `Sync`, can only be implemented for a struct/enum type, not `Alias`

#![feature(lazy_type_alias, auto_traits)]

auto trait Marker {}

struct Local;
type Alias = Local;

impl Marker for Alias {} //~ ERROR traits with a default impl, like `Marker`, cannot be implemented for type alias `Alias`