error[E0067]: invalid left-hand side of assignment
  --> $DIR/assign-non-lval-needs-deref.rs:15:16
   |
LL |     (&mut Foo) += ();
   |     ---------- ^^
   |     |
   |     cannot assign to this expression
   |
help: consider dereferencing the left-hand side of this operation
   |
LL |     *(&mut Foo) += ();
   |     +

error: aborting due to previous error

For more information about this error, try `rustc --explain E0067`.