warning: `IntoIterator` implemented for a reference type without an `iter` method
       --> src/error.rs:435:1
        |
    435 | / impl<'a> IntoIterator for &'a Error {
    436 | |     type Item = Error;
    437 | |     type IntoIter = Iter<'a>;
    438 | |
    ...   |
    443 | |     }
    444 | | }
        | |_^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_without_iter
        = note: `-W clippy::into-iter-without-iter` implied by `-W clippy::pedantic`
        = help: to override `-W clippy::pedantic` add `#[allow(clippy::into_iter_without_iter)]`
    help: consider implementing `iter`
        |
    435 +
    436 + impl Error {
    437 +     fn iter(&self) -> Iter<'a> {
    438 +         <&Self as IntoIterator>::into_iter(self)
    439 +     }
    440 + }
        |

    warning: unused import: `crate::gen::*`
       --> src/lib.rs:815:9
        |
    815 | pub use crate::gen::*;
        |         ^^^^^^^^^^^^^
        |
        = note: `#[warn(unused_imports)]` on by default

This trait is marked not public API and can only be implemented through
the public macros (custom_keyword and custom_punctuation).

Update test suite to nightly-2023-11-03

As opposed to proc_macro2::Ident.

More precise decision to parse expression after `return`, `break`, `yield`

    warning: for loop over a single element
       --> tests/test_expr.rs:333:5
        |
    333 | /     for stmt in [
    334 | |         // Parentheses required. See rust-lang/rust#87026.
    335 | |         quote! {
    336 | |             break 'label: loop { break 'label 42; };
    ...   |
    339 | |         syn::parse2::<Stmt>(stmt).unwrap_err();
    340 | |     }
        | |_____^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_element_loop
        = note: `-W clippy::single-element-loop` implied by `-W clippy::all`
        = help: to override `-W clippy::all` add `#[allow(clippy::single_element_loop)]`
    help: try
        |
    333 ~     {
    334 +         let stmt = {
    335 +         let mut _s = $crate::__private::TokenStream::new();
    336 +         $crate::quote_each_token!{_s $($tt)*}
    337 +         _s
    338 +     };
    339 +         syn::parse2::<Stmt>(stmt).unwrap_err();
    340 +     }
        |

Improve parsing of labeled loop as value expression for break