/**
 * Opt-in `--canonicalize-braces` migration-verify comparator (W2).
 *
 * The default `kern migrate native-handlers --verify` requires the compiled
 * TypeScript to stay BYTE-identical before/after. That rejects the
 * `if-non-block-then` / `while-non-block` / `for-of-non-block` lift, because the
 * native-KERN emitter always braces control-flow bodies: `if (x) return x;`
 * re-emits as `if (x) { return x; }` — a real byte difference.
 *
 * `isBraceOnlyDelta` is the SOUND relaxation that backs the opt-in mode. It
 * accepts an `after` file iff it differs from `before` ONLY by the closed,
 * semantics-preserving transform:
 *
 *     a non-block control-flow body `S`  ↔  a single-statement block `{ S }`
 *
 * applied at if-then / if-else / while / for / for-of / do body positions.
 *
 * Safety (the #1 invariant — a false-accept silently miscompiles user code):
 *   - Direction: only a BEFORE-side non-block statement may be wrapped in an
 *     AFTER-side `{ S }`. The emitter never removes braces, so this is the only
 *     shape that can occur; the reverse is rejected.
 *   - Every node outside a relaxed body position must match by source text
 *     (`getText()`), and every leaf token must match by text — so any operator
 *     change, rename, reordering, inserted/dropped statement, or moved `else`
 *     fails. Dangling-else is caught structurally: an `if` with vs without an
 *     `else` has a different child count.
 *   - The ordered list of comment texts must be identical: brace insertion
 *     never adds, drops, or rewrites a comment, so any comment delta rejects.
 * A false-reject (a correct migration left raw) is acceptable; a false-accept
 * is structurally impossible.
 */
/** True when `afterText` differs from `beforeText` only by brace-wrapping
 *  non-block control-flow bodies (and is otherwise byte-for-byte identical in
 *  tokens and comments). */
export declare function isBraceOnlyDelta(beforeText: string, afterText: string): boolean;