import { type Type } from "./types.js";
/** The wider of two types, or `unknown` when they don't coerce. */
export declare function coerce(a: Type, b: Type): Type;
/** Whether a Type is any interval-family scalar (bare or qualified). */
export declare function isIntervalType(t: Type): boolean;
/** The family's DEFAULT full-range interval type (Spark Multiply/DivideInterval always return
 *  year-to-month / day-to-second). Bare "interval" and non-intervals are returned unchanged. */
export declare function fullInterval(t: Type): Type;
/** The common type of a list (coalesce/greatest/CASE branches). Unknowns are ignored;
 *  if the known members don't coerce, the result is unknown. */
export declare function commonType(types: Type[]): Type;
/** Aggregate widening for SUM: integers → bigint, floats → double, decimal stays decimal. */
export declare function widenSum(t: Type): Type;
export declare function typeEq(a: Type, b: Type): boolean;