{"ast_node_type":"variable","tokens":[{"end":58,"kind":"keyword","start":0,"text":"let"}]}
    let pat = ctx.find_node_at_offset::<ast::IdentPat>()?;
pub(crate) fn promote_local_to_const(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
    let name = pat.name()?;