error: the `min` method cannot be invoked on a trait object
  --> $DIR/imm-ref-trait-object.rs:2:8
   |
LL |      t.min().unwrap()
   |        ^^^
   |
  ::: $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
   |
LL |         Self: Sized,
   |               ----- this has a `Sized` requirement
   |
   = note: you need `&mut dyn Iterator<Item = &u64>` instead of `&dyn Iterator<Item = &u64>`

error: aborting due to previous error