message: Optimise from_value
  Summary: Instead of doing two get_aref(), just do one.
diff: @@ -72,9 +72,13 @@ macro_rules! starlark_complex_value {
  }
  }
  - x.downcast_ref::< [< Frozen $x >] >()
  - .map(|o| $crate::values::ARef::map(o, |e| promote(e)))
  - .or_else(|| x.downcast_ref::<$x<'v>>())
  + let aref = $crate::values::ARef::map(x.get_aref(), |e| e.as_dyn_any());
  + match $crate::values::ARef::filter_map(aref, |e| e.downcast_ref::< $x<'v> >()) {
  + Ok(res) => Some(res),
  + Err(aref) => {
  + $crate::values::ARef::filter_map(aref, |e| e.downcast_ref::< [< Frozen $x >] >().map(promote)).ok()
  + }
  + }
  }
  #[allow(dead_code)]
  