Rust: doubly nested abbreviations break extraction

[gebner]

module Rustabbrev2

type foo = { b: bool; }
type bar = { c: foo; }

let f (x: bool) = 0ul
let g (x: bar) = f x.c.b

let main_ () = g { c = { b = true } }

This fails with:

✔ [Monomorphization] ⏱️ 42ms
✔ [Inlining] ⏱️ 5ms
✔ [Pattern matches compilation] ⏱️ 4ms
✔ [Structs + Simplify 2] ⏱️ 6ms
✔ [Drop] ⏱️ <1ms
ERROR translating Rustabbrev2.g: Krml.Warn.Fatal("type mismatch;\n  e=@0\n  t=rustabbrev2::foo (verbose: (MiniRust.Name ([\"rustabbrev2\"; \"foo\"], [])))\n  t_ret=bool (verbose: (MiniRust.Constant <opaque>))\n  x=@0")

1 total errors
ERROR looking up: rustabbrev2::g
Fatal error: exception Not_found