`TokenStream` assumes that its subtree's delimeter is `None`, and this
should be encoded in the type system instead of having a delimiter field
that is mostly ignored.
`tt::Subtree` is just `pub delimiter: Option<Delimiter>, pub
token_trees: Vec<TokenTree>`, so a Subtree that is statically guaranteed
not to have a delimiter is just Vec<TokenTree>.
TokenStream holds a `tt::Subtree` but assumes its `delimiter` is always
`None`. In particular, the iterator implementation iterates over the
inner `token_trees` and ignores the `delimiter`.
However, `TokenStream::from_str` violated this assumption when the input
consists of a single Group by producing a Subtree with an outer
delimiter, which was ignored as seen by a procedural macro.
In this case, wrap an extra level of Subtree around it.
Fixes#7810Fixes#7875
7047: Add force_show_panics flag for proc-macro bridge r=jonas-schievink a=edwin0cheng
https://github.com/rust-lang/rust/pull/75082 and https://github.com/rust-lang/rust/pull/76292 added a new flag in `proc_macro::Bridge` such that the ABI was changed. These ABI changing are the reason of some weird panics which caused #6880 and maybe related to the panic mentioned in #6820.
These changes are landed on rust stable 1.48 so I think it is okay to apply it now.
fixes#6880
r @jonas-schievink
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
It's very useful when `pub` is equivalent to "this is crate's public
API", let's enforce this!
Ideally, we should enforce it for local `cargo test`, and only during
CI, but that needs https://github.com/rust-lang/cargo/issues/5034.
