# Parser.Fail

A parser that always produces `never`.

## Signatures

```ts
interface Fail extends TypeFunction<string, never> {
    readonly return: never;
}
```

## Why

Failure is the branch-selection signal used by type-level alternatives.

## Ownership and lifetime

TypeScript instantiates `Fail` while parsing a string-literal input; partial results and unconsumed text exist only in the resulting type.

## Property: return

Computes this type lambda's parse result for its current input.

## Property: return: Why

The local type-function protocol evaluates each parser combinator through this member without a parallel runtime object.

## Property: return: Ownership and lifetime

TypeScript evaluates `Fail.return` when the surrounding parser is applied; the associated result is erased and retains no input at runtime.