pub fn block_diff_start(
block_old: *mut AstStatBlock,
block_new: *mut AstStatBlock,
nearest_statement_new_ast: *mut AstStat,
) -> Option<Position>pub fn block_diff_start(
block_old: *mut AstStatBlock,
block_new: *mut AstStatBlock,
nearest_statement_new_ast: *mut AstStat,
) -> Option<Position>