Comparison of different enumeration types error

🔍 Search Terms

"enums", "enum comparison"

✅ Viability Checklist

• 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 isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
• This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

⭐ Suggestion

Show type-check error on different enumeration types comparing

📃 Motivating Example

enum Month {
    Jan, Feb, Mar, Apr, May, Jun,
    Jul, Aug, Sep, Oct, Nov, Dec
}

enum Week { Mon, Tue, Wed, Thu, Fri, Sat, Sun }

console.log('Month vs Month', Month.May > Month.Nov) // false
console.log('Week vs Week', Week.Wed > Week.Mon) // true

console.log('Equals', Week.Sun === Month.Nov) // false (type-check error)
console.log('Week vs Month', Week.Sun > Month.Nov) // false (expected type-check error?)

Comparing the equality of different enums results a type-check error:

This comparison appears to be unintentional because the types 'Week' and 'Month' have no overlap. (2367)

But no error on >, < or >=, <=

Error examples:
C

Rust

💻 Use Cases

1. What do you want to use this for?
   Comparison operations between non-overlapping enum types

まず、issue にある enum の比較例を TypeScript のテストケースで再現し、既存の等価性診断を関係演算子と比較します。異なる enum 型間の比較が、出力される JavaScript の動作を変更せずに、意図した型チェックエラーを一貫して生成するようになれば、変更は完了です。