Never returning functions should disable getter return requirement

Suggestion

declare const error: () => never;
const o = { get p() { error(); } };

Produces the error A 'get' accessor must return a value.(2378). Throwing an error directly would not. I feel similar to https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#better-support-for-never-returning-functions, a never-returning-function should have the same effect.

Afaik "control flow analysis happens before typechecking", so this would only work, when the function has a declared type. That's in line with the linked existing improvement in TS 3.7, and to be expected.

🔍 Search Terms

Getter Get accessor must return a value never returning function error throw

✅ Viability Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

まず、getter の戻り値のチェックと、決して戻らないと宣言された関数の制御フロー処理を、TypeScript 3.7 のリリースノートをコンテキストとして使いながら追跡します。never を返すと宣言された関数を呼び出す getter の回帰テストを追加し、通常の戻り値を返さないパスでは引き続き値が必要である一方、getter の診断が抑制されることを確認します。