// SPDX-License-Identifier: Apache-2.0 OR MIT use proc_macro2::{Delimiter, TokenStream, TokenTree};use std::hash::{Hash, Hasher}; pub(crate) struct TokenTreeHelper<'a>(pub &'a TokenTree); impl<'a> PartialEq for TokenTreeHelper<'a> {    fn eq(&self, other: &Self) -> bool {        use proc_macro2::Spacing;         match (self.0, other.0) {            (TokenTree::Group(g1), TokenTree::Group(g2)) => {                match (g1.delimiter(), g2.delimiter()) {                    (Delimiter::Parenthesis, Delimiter::Parenthesis)                    | (Delimiter::Brace, Delimiter::Brace)                    | (Delimiter::Bracket, Delimiter::Bracket)                    | (Delimiter::None, Delimiter::None) => {}                    _ => return false,                }                 let s1 = g1.stream().into_iter();                let mut s2 = g2.stream().into_iter();                 for item1 in s1 {                    let item2 = match s2.next() {                        Some(item) => item,                        None => return false,                    };                    if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) {                        return false;                    }                }                s2.next().is_none()            }            (TokenTree::Punct(o1), TokenTree::Punct(o2)) => {                o1.as_char() == o2.as_char()                    && match (o1.spacing(), o2.spacing()) {                        (Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true,                        _ => false,                    }            }            (TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(),            (TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2,            _ => false,        }    }} impl<'a> Hash for TokenTreeHelper<'a> {    fn hash<H: Hasher>(&self, h: &mut H) {        use proc_macro2::Spacing;         match self.0 {            TokenTree::Group(g) => {                0u8.hash(h);                match g.delimiter() {                    Delimiter::Parenthesis => 0u8.hash(h),                    Delimiter::Brace => 1u8.hash(h),                    Delimiter::Bracket => 2u8.hash(h),                    Delimiter::None => 3u8.hash(h),                }                 for item in g.stream() {                    TokenTreeHelper(&item).hash(h);                }                0xFFu8.hash(h); // terminator w/ a variant we don't normally hash            }            TokenTree::Punct(op) => {                1u8.hash(h);                op.as_char().hash(h);                match op.spacing() {                    Spacing::Alone => 0u8.hash(h),                    Spacing::Joint => 1u8.hash(h),                }            }            TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h),            TokenTree::Ident(word) => (3u8, word).hash(h),        }    }} pub(crate) struct TokenStreamHelper<'a>(pub &'a TokenStream); impl<'a> PartialEq for TokenStreamHelper<'a> {    fn eq(&self, other: &Self) -> bool {        let left = self.0.clone().into_iter().collect::<Vec<_>>();        let right = other.0.clone().into_iter().collect::<Vec<_>>();        if left.len() != right.len() {            return false;        }        for (a, b) in left.into_iter().zip(right) {            if TokenTreeHelper(&a) != TokenTreeHelper(&b) {                return false;            }        }        true    }} impl<'a> Hash for TokenStreamHelper<'a> {    fn hash<H: Hasher>(&self, state: &mut H) {        let tts = self.0.clone().into_iter().collect::<Vec<_>>();        tts.len().hash(state);        for tt in tts {            TokenTreeHelper(&tt).hash(state);        }    }}