export type EnvCheck<T = Record<string, unknown>> = {
    /** Vars this check is about: used to attribute the error, and to SKIP the
     *  check when any of them already failed validation ("both missing" must not
     *  also report as "both equal"). */
    vars: readonly string[];
    /** Return false (or throw) to fail. Receives the cleaned, coerced values. */
    check: (env: T) => boolean;
    /** Why it failed, phrased as an instruction to the operator. */
    message: string;
};
/** At most one of `vars` may be set. */
export declare const mutuallyExclusive: <T = Record<string, unknown>>(vars: readonly string[], message?: string) => EnvCheck<T>;
/** All of `vars` must hold distinct values (e.g. two roles that cannot be the
 *  same role — one needs BYPASSRLS, the other must be subject to RLS). */
export declare const distinct: <T = Record<string, unknown>>(vars: readonly string[], message?: string) => EnvCheck<T>;
/** When `flag` is truthy, every var in `vars` must be set — a feature flag that
 *  turns other vars into requirements. */
export declare const requiredWhen: <T = Record<string, unknown>>(flag: string, vars: readonly string[], message?: string) => EnvCheck<T>;
/** Run the checks whose vars all validated; return one message per failure. */
export declare const runChecks: <T>(checks: readonly EnvCheck<T>[], cleaned: T, failedVars: ReadonlySet<string>) => {
    vars: readonly string[];
    message: string;
}[];