Record spread from smaller to bigger record type set doesn't work

I observed some weird behavior while working on my app, so I tried to reduce the problem to a minimal example.

type a = {
  title: string,
  ingredients: array<string>,
}

type b = {
  ...a,
  parsedIngredients: array<string>,
}

// This works
let a: a = {
  title: "Pizza",
  ingredients: ["1 EL Oil", "1 EL flour"],
}

// EXPECTED: This should compile
let b: b = {
  // ERROR: This has type `a`, but it's expected to have type `b`
  ...a,
  parsedIngredients: ["Oil", "Flour"],
}

I don't know if I misunderstood the record type spread feature, but IMO from an intuition perspective I'd expect value b to initialize just fine, since we are essentially spreading in all the values that a has, plus the parsedIngredients value that's required from b.

Does this work as expected?

Riproduci prima l’esempio minimo di record-spread nell’issue; non sono indicati alcun file sorgente, test o punto di ingresso del compilatore. Traccia il comportamento del controllo dei tipi di record-spread e aggiungi un test di regressione che mostri se un record più piccolo può inizializzare il tipo più grande, quindi conferma il risultato atteso.