/**
 * Performance lint matcher: is a declaration reading a --sv-* value (direct
 * or through one level of custom-property indirection) into a property that
 * cannot be composited? Pure, so it is unit-testable without a browser; the
 * runtime scanner in index.ts walks the real CSSOM and calls lintDeclaration
 * per rule.
 */
export declare const NON_COMPOSITABLE: Set<string>;
export declare function stripComments(css: string): string;
export interface LintViolation {
    selector: string;
    property: string;
    reason: string;
}
/** customProps: declared-name -> every distinct value seen for it, for
 * one-level indirection (`top: var(--x); --x: var(--sv-t)`). A name can have
 * more than one candidate value (the caller resolves same-rule declarations
 * unambiguously; a name declared in more than one rule, without a real
 * cascade, can only be "one of these"), so every candidate is checked: any
 * of them reading a --sv-* value is enough to flag the declaration, rather
 * than picking whichever a plain last-write-wins map happened to keep.
 * Resolution stops after a few hops to stay cheap and never loop on a
 * self-referencing custom property. */
export declare function lintDeclaration(selector: string, property: string, value: string, customProps?: Map<string, string[]>): LintViolation | null;
/** Naive selector { decls } extraction for unit tests: not a CSS parser,
 * good enough for fixture text (no nested @media). The runtime scanner in
 * overlay.ts's scanStylesheets() uses the real CSSOM the same way: a name
 * declared and consumed inside the SAME rule resolves to that rule's own
 * value regardless of stylesheet order; a name declared elsewhere falls
 * back to every distinct value seen for it anywhere (ADU review: a global
 * last-write-wins map missed a same-rule violation depending on the order
 * two unrelated rules happened to declare the same custom property name). */
export declare function scanCssText(cssText: string): LintViolation[];