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
View file

@ -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),

13
tests/ui/proc-macro/nodelim-groups.rs
View file

@ -19,4 +19,17 @@ macro_rules! expand_it {
fn main() {
expand_it!(1 + (25) + 1);
expand_it!(("hello".len()) ("world".len()));
f();
}
// The key thing here is to produce a single `None`-delimited `Group`, even
// though there is multiple levels of macros.
macro_rules! m5 { ($e:expr) => { print_bang_consume!($e) }; }
macro_rules! m4 { ($e:expr) => { m5!($e); } }
macro_rules! m3 { ($e:expr) => { m4!($e); } }
macro_rules! m2 { ($e:expr) => { m3!($e); } }
macro_rules! m1 { ($e:expr) => { m2!($e); } }
fn f() {
m1!(123);
}

15
tests/ui/proc-macro/nodelim-groups.stdout
View file

@ -165,3 +165,18 @@ PRINT-BANG INPUT (DEBUG): TokenStream [
span: $DIR/nodelim-groups.rs:16:52: 16:59 (#8),
},
]
PRINT-BANG INPUT (DISPLAY): 123
PRINT-BANG INPUT (DEBUG): TokenStream [
Group {
delimiter: None,
stream: TokenStream [
Literal {
kind: Integer,
symbol: "123",
suffix: None,
span: $DIR/nodelim-groups.rs:34:9: 34:12 (#0),
},
],
span: $DIR/nodelim-groups.rs:27:54: 27:56 (#16),
},
]