PromptOptions union type does not work well in TypeScript 3.8.x

[IngvarKofoed]

The following code

const { doSomething } = await prompt<{ doSomething: 'Yes' | 'No' }>({
  type: 'autocomplete',
  name: 'doSomething',
  message: 'Some Message',
  choices: ['Yes', 'No'],
  initial: 'Yes'
});

Gives the following compile error:

Argument of type '{ type: string; name: string; message: string; choices: string[]; initial: string; }' is not assignable to parameter of type 'ArrayPromptOptions | BasePromptOptions | BooleanPromptOptions | StringPromptOptions | ... 4 more ... | (ArrayPromptOptions | ... 6 more ... | ((this: Enquirer<...>) => PromptOptions))[]'.
  Object literal may only specify known properties, and 'choices' does not exist in type 'BasePromptOptions'.ts(2345)

The problem is the type property on BasePromptOptions. This breaks the union type PromptOptions so that the compiler does not see that type as the discriminant.

Versions:
enquirer: 2.3.2
typescript: 3.8.3
node: 12.12.0
yarn: 1.22.0