type EvolveTransform<O> = Partial<{
    [K in keyof O]: (a: O[K]) => O[K];
}>;
type StrictKeys<O, T> = T extends Record<string, any> ? Exclude<keyof T, keyof O> extends never ? T : T & {
    [K in `Invalid key: ${Exclude<keyof T, keyof O> & string}`]: never;
} : never;
type Evolved<O, T> = {
    [K in keyof O]: K extends keyof T ? T[K] extends (a: any) => infer R ? R : O[K] : O[K];
};
/** Immutably updates fields of a struct by applying transform functions. Wraps Effect's `Struct.evolve` with stricter key checking. */
export declare const evo: {
    <O, const T extends EvolveTransform<O>>(t: StrictKeys<O, T>): (obj: O) => Evolved<O, T>;
    <O, const T extends EvolveTransform<O>>(obj: O, t: StrictKeys<O, T>): Evolved<O, T>;
};
/** Creates a variant of `evo` whose transforms are checked against a supertype. Useful in generic contexts where `evo`'s `StrictKeys` can't resolve `keyof` on an open type parameter. The returned function evolves a subtype model, preserving all fields not in the transform, and returns the subtype. */
export declare const makeConstrainedEvo: <Constraint extends Record<string, unknown>>() => <Model extends Constraint>(model: Model, transforms: EvolveTransform<Constraint>) => Model;
export {};
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