# TS2678: Type '…' is not comparable to type '…'.

> A switch case value can never equal the switch expression because their types don't overlap. Fix the case value or the type.

## What it means

The checker compares each `case` value with the `switch` expression. When their types have no
values in common, that case can never match.

## Example

```ts
function f(kind: "a" | "b") {
  switch (kind) {
    case "c":
      break;
  }
}
export {};
```

## How to fix

- Correct the case value (often a typo or a stale value).
- If the value can really occur, add it to the switched value's type.

Source: https://ts-r.dev/errors/TS2678/