{"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
    let source_file = ctx.find_node_at_offset::<ast::SourceFile>()?;
pub(crate) fn move_to_mod_rs(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
    let module = ctx.sema.file_to_module_def(ctx.vfs_file_id())?;