bjoernager/rust
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More denesting of invisibly-delimited groups.

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This time when converting them to proc-macro `Group` form.
This commit is contained in:
Nicholas Nethercote 2024-09-24 15:24:26 +10:00
parent 293fe0a966
commit 3378ee1a4f
3 changed files with 47 additions and 1 deletions
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20
compiler/rustc_expand/src/proc_macro_server.rs
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@ -115,7 +115,7 @@ impl FromInternal<(TokenStream, &mut Rustc<'_, '_>)> for Vec<TokenTree<TokenStre
while let Some(tree) = iter.next() {
let (Token { kind, span }, joint) = match tree.clone() {
tokenstream::TokenTree::Delimited(span, _, delim, stream) => {
tokenstream::TokenTree::Delimited(span, _, mut delim, mut stream) => {
// We used to have an alternative behaviour for crates that
// needed it: a hack used to pass AST fragments to
// attribute and derive macros as a single nonterminal
@ -131,6 +131,24 @@ impl FromInternal<(TokenStream, &mut Rustc<'_, '_>)> for Vec<TokenTree<TokenStre
rustc.psess(),
);
}
// In `mk_delimited` we avoid nesting invisible delimited
// of the same `MetaVarKind`. Here we do the same but
// ignore the `MetaVarKind` because it is discarded when we
// convert it to a `Group`.
while let Delimiter::Invisible(InvisibleOrigin::MetaVar(_)) = delim {
if stream.len() == 1
&& let tree = stream.iter().next().unwrap()
&& let tokenstream::TokenTree::Delimited(_, _, delim2, stream2) = tree
&& let Delimiter::Invisible(InvisibleOrigin::MetaVar(_)) = delim2
{
delim = *delim2;
stream = stream2.clone();
} else {
break;
}
}
trees.push(TokenTree::Group(Group {
delimiter: pm::Delimiter::from_internal(delim),
stream: Some(stream),