# assertUniqueDecodedRouteParamNames

Throws when a Route AST decodes the same parameter name more than once.

## Signatures

```ts
export declare function assertUniqueDecodedRouteParamNames(ast: RouteAst): void;
```

## Why

Ambiguous merged records fail at route construction rather than silently overwriting values.

## Ownership and lifetime

`assertUniqueDecodedRouteParamNames` performs one synchronous traversal, retains nothing, and throws before a Route is constructed when decoded names collide.