Error message displays computed name '[attr]' instead of key value

🔎 Search Terms

computed property, error message

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about computed properties

⏯ Playground Link

https://tsplay.dev/WyV2bw

💻 Code

type Unit =
  | {
      name: string;
      stength: number;
    }
  | {
      name: string;
      magic: number;
    };

const createUnit = (
  name: string,
  attr: "strength" | "magic",
  power: number,
): Unit => {
  return attr === "strength"
    ? { name, [attr]: power } // <-- error here
    : { name, [attr]: power };
};

🙁 Actual behavior

Error message displays "Object literal may only specify known properties, and '[attr]' does not exist in type 'Unit'".

🙂 Expected behavior

Error message should display that "strength" doesn't exist on Unit. (and possibly even recommend "stength" instead)

Additional information about the issue

No response

Reproduce the diagnostic from the TypeScript code sample in the linked Playground and compare the actual '[attr]' message with the expected 'strength' wording. Trace the computed-property error reporting path in the compiler and add coverage for the shown example, including the suggested 'stength' spelling if supported. Done means the diagnostic reports the resolved key value rather than the source expression.