{"ast_node_type":"function","tokens":[{"end":69,"kind":"keyword","start":0,"text":"fn"}]}
    fn new(state: impl Into<DebugSolver<I>>) -> ProofTreeBuilder<D> {
impl<D: SolverDelegate<Interner = I>, I: Interner> ProofTreeBuilder<D> {
        ProofTreeBuilder { state: Some(Box::new(state.into())), _infcx: PhantomData }