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?

Reproduce the minimal record-spread example in the issue first; no source file, test, or compiler entry point is named. Trace the record-spread type-checking behavior and add a regression test showing whether a smaller record can initialize the larger type, then confirm the expected result.