union type {x, y} | {x, z} sometimes incorrectly allows {x, y, z} #43691
Description
Bug Report
🔎 Search Terms
union type
🕗 Version & Regression Information
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about union types
⏯ Playground Link
Playground link with relevant code
💻 Code
type XY<T> = {
x: T;
y: T;
};
type XZ<U> = {
x: U;
z: U;
};
// This is correctly an error
const a: XY<boolean> | XZ<string> = { x: true, y: true, z: 'z' };
// This is incorrectly allowed
const b: XY<number> | XZ<string> = { x: 1, y: 1, z: 'z' };