import { type SourceSpan } from "../../parse/parser.js";
export type Diagnostic = {
    code: "AS-FRONTMATTER-FIELD-UNUSED";
    severity: "info";
    message: string;
    filename: string;
    line: number;
    column: number;
    span: SourceSpan;
};
export declare function AS_FRONTMATTER_FIELD_UNUSED(source: string, options?: {
    filename?: string;
    frontmatterFields?: readonly string[];
}): Diagnostic[];