Optional discriminated union's callback parameter type is not inferred #46847
Description
Bug Report
Optional discriminated union's callback parameter type is not inferred
🔎 Search Terms
🕗 Version & Regression Information
typescript@4.4.4
⏯ Playground Link
💻 Code
type A = {
type?: 'A',
a: (c: { d: number }) => void;
}
type B = {
type: 'B',
a: (c: { d: number, c: string }) => void;
}
type ABC = A | B ;
var a: ABC[] | Record<string, ABC[]> = [
{
a: (params) => {
}
}
]🙁 Actual behavior
Parameters of method 'a' can not be inferred correctly.
🙂 Expected behavior
Parameters of method 'a 'can be inferred correctly: {d: number}