1 //! FIXME: write short doc here
3 use parser::{FragmentKind, ParseError, TreeSink};
4 use rustc_hash::FxHashMap;
6 ast::{self, make::tokens::doc_comment},
7 tokenize, AstToken, Parse, SmolStr, SyntaxKind,
9 SyntaxNode, SyntaxToken, SyntaxTreeBuilder, TextRange, TextSize, Token as RawToken, T,
11 use tt::buffer::{Cursor, TokenBuffer};
13 use crate::ExpandError;
14 use crate::{subtree_source::SubtreeTokenSource, tt_iter::TtIter};
16 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
17 pub enum TokenTextRange {
23 pub fn by_kind(self, kind: SyntaxKind) -> Option<TextRange> {
25 TokenTextRange::Token(it) => Some(it),
26 TokenTextRange::Delimiter(it) => match kind {
27 T!['{'] | T!['('] | T!['['] => Some(TextRange::at(it.start(), 1.into())),
28 T!['}'] | T![')'] | T![']'] => {
29 Some(TextRange::at(it.end() - TextSize::of('}'), 1.into()))
37 /// Maps `tt::TokenId` to the relative range of the original token.
38 #[derive(Debug, PartialEq, Eq, Clone, Default)]
40 /// Maps `tt::TokenId` to the *relative* source range.
41 entries: Vec<(tt::TokenId, TokenTextRange)>,
44 /// Convert the syntax tree (what user has written) to a `TokenTree` (what macro
46 pub fn ast_to_token_tree(ast: &impl ast::AstNode) -> Option<(tt::Subtree, TokenMap)> {
47 syntax_node_to_token_tree(ast.syntax())
50 /// Convert the syntax node to a `TokenTree` (what macro
52 pub fn syntax_node_to_token_tree(node: &SyntaxNode) -> Option<(tt::Subtree, TokenMap)> {
53 let global_offset = node.text_range().start();
54 let mut c = Convertor::new(node, global_offset);
55 let subtree = c.go()?;
56 c.id_alloc.map.entries.shrink_to_fit();
57 Some((subtree, c.id_alloc.map))
60 // The following items are what `rustc` macro can be parsed into :
61 // link: https://github.com/rust-lang/rust/blob/9ebf47851a357faa4cd97f4b1dc7835f6376e639/src/libsyntax/ext/expand.rs#L141
62 // * Expr(P<ast::Expr>) -> token_tree_to_expr
63 // * Pat(P<ast::Pat>) -> token_tree_to_pat
64 // * Ty(P<ast::Ty>) -> token_tree_to_ty
65 // * Stmts(SmallVec<[ast::Stmt; 1]>) -> token_tree_to_stmts
66 // * Items(SmallVec<[P<ast::Item>; 1]>) -> token_tree_to_items
68 // * TraitItems(SmallVec<[ast::TraitItem; 1]>)
69 // * AssocItems(SmallVec<[ast::AssocItem; 1]>)
70 // * ForeignItems(SmallVec<[ast::ForeignItem; 1]>
72 pub fn token_tree_to_syntax_node(
74 fragment_kind: FragmentKind,
75 ) -> Result<(Parse<SyntaxNode>, TokenMap), ExpandError> {
76 let buffer = match tt {
77 tt::Subtree { delimiter: None, token_trees } => {
78 TokenBuffer::from_tokens(token_trees.as_slice())
80 _ => TokenBuffer::from_subtree(tt),
82 let mut token_source = SubtreeTokenSource::new(&buffer);
83 let mut tree_sink = TtTreeSink::new(buffer.begin());
84 parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
85 if tree_sink.roots.len() != 1 {
86 return Err(ExpandError::ConversionError);
88 //FIXME: would be cool to report errors
89 let (parse, range_map) = tree_sink.finish();
90 Ok((parse, range_map))
93 /// Convert a string to a `TokenTree`
94 pub fn parse_to_token_tree(text: &str) -> Option<(tt::Subtree, TokenMap)> {
95 let (tokens, errors) = tokenize(text);
96 if !errors.is_empty() {
100 let mut conv = RawConvertor {
102 offset: TextSize::default(),
103 inner: tokens.iter(),
104 id_alloc: TokenIdAlloc {
105 map: Default::default(),
106 global_offset: TextSize::default(),
111 let subtree = conv.go()?;
112 Some((subtree, conv.id_alloc.map))
115 /// Split token tree with seperate expr: $($e:expr)SEP*
116 pub fn parse_exprs_with_sep(tt: &tt::Subtree, sep: char) -> Vec<tt::Subtree> {
117 if tt.token_trees.is_empty() {
121 let mut iter = TtIter::new(tt);
122 let mut res = Vec::new();
124 while iter.peek_n(0).is_some() {
125 let expanded = iter.expect_fragment(FragmentKind::Expr);
126 if expanded.err.is_some() {
130 res.push(match expanded.value {
132 Some(tt @ tt::TokenTree::Leaf(_)) => {
133 tt::Subtree { delimiter: None, token_trees: vec![tt] }
135 Some(tt::TokenTree::Subtree(tt)) => tt,
138 let mut fork = iter.clone();
139 if fork.expect_char(sep).is_err() {
145 if iter.peek_n(0).is_some() {
146 res.push(tt::Subtree { delimiter: None, token_trees: iter.into_iter().cloned().collect() });
153 pub fn token_by_range(&self, relative_range: TextRange) -> Option<tt::TokenId> {
154 let &(token_id, _) = self.entries.iter().find(|(_, range)| match range {
155 TokenTextRange::Token(it) => *it == relative_range,
156 TokenTextRange::Delimiter(it) => {
157 let open = TextRange::at(it.start(), 1.into());
158 let close = TextRange::at(it.end() - TextSize::of('}'), 1.into());
159 open == relative_range || close == relative_range
165 pub fn range_by_token(&self, token_id: tt::TokenId) -> Option<TokenTextRange> {
166 let &(_, range) = self.entries.iter().find(|(tid, _)| *tid == token_id)?;
170 fn insert(&mut self, token_id: tt::TokenId, relative_range: TextRange) {
171 self.entries.push((token_id, TokenTextRange::Token(relative_range)));
176 token_id: tt::TokenId,
177 open_relative_range: TextRange,
178 close_relative_range: TextRange,
180 let res = self.entries.len();
181 let cover = open_relative_range.cover(close_relative_range);
183 self.entries.push((token_id, TokenTextRange::Delimiter(cover)));
187 fn update_close_delim(&mut self, idx: usize, close_relative_range: TextRange) {
188 let (_, token_text_range) = &mut self.entries[idx];
189 if let TokenTextRange::Delimiter(dim) = token_text_range {
190 let cover = dim.cover(close_relative_range);
191 *token_text_range = TokenTextRange::Delimiter(cover);
195 fn remove_delim(&mut self, idx: usize) {
196 // FIXME: This could be accidentally quadratic
197 self.entries.remove(idx);
201 /// Returns the textual content of a doc comment block as a quoted string
202 /// That is, strips leading `///` (or `/**`, etc)
203 /// and strips the ending `*/`
204 /// And then quote the string, which is needed to convert to `tt::Literal`
205 fn doc_comment_text(comment: &ast::Comment) -> SmolStr {
206 let prefix_len = comment.prefix().len();
207 let mut text = &comment.text()[prefix_len..];
209 // Remove ending "*/"
210 if comment.kind().shape == ast::CommentShape::Block {
211 text = &text[0..text.len() - 2];
215 // Note that `tt::Literal` expect an escaped string
216 let text = format!("{:?}", text.escape_debug().to_string());
220 fn convert_doc_comment(token: &syntax::SyntaxToken) -> Option<Vec<tt::TokenTree>> {
221 let comment = ast::Comment::cast(token.clone())?;
222 let doc = comment.kind().doc?;
224 // Make `doc="\" Comments\""
225 let meta_tkns = vec![mk_ident("doc"), mk_punct('='), mk_doc_literal(&comment)];
228 let mut token_trees = vec![mk_punct('#')];
229 if let ast::CommentPlacement::Inner = doc {
230 token_trees.push(mk_punct('!'));
232 token_trees.push(tt::TokenTree::from(tt::Subtree {
233 delimiter: Some(tt::Delimiter {
234 kind: tt::DelimiterKind::Bracket,
235 id: tt::TokenId::unspecified(),
237 token_trees: meta_tkns,
240 return Some(token_trees);
243 fn mk_ident(s: &str) -> tt::TokenTree {
244 tt::TokenTree::from(tt::Leaf::from(tt::Ident {
246 id: tt::TokenId::unspecified(),
250 fn mk_punct(c: char) -> tt::TokenTree {
251 tt::TokenTree::from(tt::Leaf::from(tt::Punct {
253 spacing: tt::Spacing::Alone,
254 id: tt::TokenId::unspecified(),
258 fn mk_doc_literal(comment: &ast::Comment) -> tt::TokenTree {
259 let lit = tt::Literal { text: doc_comment_text(comment), id: tt::TokenId::unspecified() };
261 tt::TokenTree::from(tt::Leaf::from(lit))
265 struct TokenIdAlloc {
267 global_offset: TextSize,
272 fn alloc(&mut self, absolute_range: TextRange) -> tt::TokenId {
273 let relative_range = absolute_range - self.global_offset;
274 let token_id = tt::TokenId(self.next_id);
276 self.map.insert(token_id, relative_range);
280 fn open_delim(&mut self, open_abs_range: TextRange) -> (tt::TokenId, usize) {
281 let token_id = tt::TokenId(self.next_id);
283 let idx = self.map.insert_delim(
285 open_abs_range - self.global_offset,
286 open_abs_range - self.global_offset,
291 fn close_delim(&mut self, idx: usize, close_abs_range: Option<TextRange>) {
292 match close_abs_range {
294 self.map.remove_delim(idx);
297 self.map.update_close_delim(idx, close - self.global_offset);
303 /// A Raw Token (straightly from lexer) convertor
304 struct RawConvertor<'a> {
307 id_alloc: TokenIdAlloc,
308 inner: std::slice::Iter<'a, RawToken>,
311 trait SrcToken: std::fmt::Debug {
312 fn kind(&self) -> SyntaxKind;
314 fn to_char(&self) -> Option<char>;
316 fn to_text(&self) -> SmolStr;
319 trait TokenConvertor {
320 type Token: SrcToken;
322 fn go(&mut self) -> Option<tt::Subtree> {
323 let mut subtree = tt::Subtree::default();
324 subtree.delimiter = None;
325 while self.peek().is_some() {
326 self.collect_leaf(&mut subtree.token_trees);
328 if subtree.token_trees.is_empty() {
331 if subtree.token_trees.len() == 1 {
332 if let tt::TokenTree::Subtree(first) = &subtree.token_trees[0] {
333 return Some(first.clone());
339 fn collect_leaf(&mut self, result: &mut Vec<tt::TokenTree>) {
340 let (token, range) = match self.bump() {
345 let k: SyntaxKind = token.kind();
347 if let Some(tokens) = self.convert_doc_comment(&token) {
348 result.extend(tokens);
353 result.push(if k.is_punct() {
354 assert_eq!(range.len(), TextSize::of('.'));
355 let delim = match k {
356 T!['('] => Some((tt::DelimiterKind::Parenthesis, T![')'])),
357 T!['{'] => Some((tt::DelimiterKind::Brace, T!['}'])),
358 T!['['] => Some((tt::DelimiterKind::Bracket, T![']'])),
362 if let Some((kind, closed)) = delim {
363 let mut subtree = tt::Subtree::default();
364 let (id, idx) = self.id_alloc().open_delim(range);
365 subtree.delimiter = Some(tt::Delimiter { kind, id });
367 while self.peek().map(|it| it.kind() != closed).unwrap_or(false) {
368 self.collect_leaf(&mut subtree.token_trees);
370 let last_range = match self.bump() {
372 // For error resilience, we insert an char punct for the opening delim here
373 self.id_alloc().close_delim(idx, None);
374 let leaf: tt::Leaf = tt::Punct {
375 id: self.id_alloc().alloc(range),
376 char: token.to_char().unwrap(),
377 spacing: tt::Spacing::Alone,
380 result.push(leaf.into());
381 result.extend(subtree.token_trees);
386 self.id_alloc().close_delim(idx, Some(last_range));
389 let spacing = match self.peek() {
391 if next.kind().is_trivia()
392 || next.kind() == T!['[']
393 || next.kind() == T!['{']
394 || next.kind() == T!['('] =>
398 Some(next) if next.kind().is_punct() => tt::Spacing::Joint,
399 _ => tt::Spacing::Alone,
401 let char = match token.to_char() {
404 panic!("Token from lexer must be single char: token = {:#?}", token);
407 tt::Leaf::from(tt::Punct { char, spacing, id: self.id_alloc().alloc(range) }).into()
410 macro_rules! make_leaf {
412 tt::$i { id: self.id_alloc().alloc(range), text: token.to_text() }.into()
415 let leaf: tt::Leaf = match k {
416 T![true] | T![false] => make_leaf!(Ident),
417 IDENT => make_leaf!(Ident),
418 k if k.is_keyword() => make_leaf!(Ident),
419 k if k.is_literal() => make_leaf!(Literal),
421 let char_unit = TextSize::of('\'');
422 let r = TextRange::at(range.start(), char_unit);
423 let apostrophe = tt::Leaf::from(tt::Punct {
425 spacing: tt::Spacing::Joint,
426 id: self.id_alloc().alloc(r),
428 result.push(apostrophe.into());
430 let r = TextRange::at(range.start() + char_unit, range.len() - char_unit);
431 let ident = tt::Leaf::from(tt::Ident {
432 text: SmolStr::new(&token.to_text()[1..]),
433 id: self.id_alloc().alloc(r),
435 result.push(ident.into());
445 fn convert_doc_comment(&self, token: &Self::Token) -> Option<Vec<tt::TokenTree>>;
447 fn bump(&mut self) -> Option<(Self::Token, TextRange)>;
449 fn peek(&self) -> Option<Self::Token>;
451 fn id_alloc(&mut self) -> &mut TokenIdAlloc;
454 impl<'a> SrcToken for (&'a RawToken, &'a str) {
455 fn kind(&self) -> SyntaxKind {
459 fn to_char(&self) -> Option<char> {
460 self.1.chars().next()
463 fn to_text(&self) -> SmolStr {
468 impl RawConvertor<'_> {}
470 impl<'a> TokenConvertor for RawConvertor<'a> {
471 type Token = (&'a RawToken, &'a str);
473 fn convert_doc_comment(&self, token: &Self::Token) -> Option<Vec<tt::TokenTree>> {
474 convert_doc_comment(&doc_comment(token.1))
477 fn bump(&mut self) -> Option<(Self::Token, TextRange)> {
478 let token = self.inner.next()?;
479 let range = TextRange::at(self.offset, token.len);
480 self.offset += token.len;
482 Some(((token, &self.text[range]), range))
485 fn peek(&self) -> Option<Self::Token> {
486 let token = self.inner.as_slice().get(0);
489 let range = TextRange::at(self.offset, it.len);
490 (it, &self.text[range])
494 fn id_alloc(&mut self) -> &mut TokenIdAlloc {
500 id_alloc: TokenIdAlloc,
501 current: Option<SyntaxToken>,
503 punct_offset: Option<(SyntaxToken, TextSize)>,
507 fn new(node: &SyntaxNode, global_offset: TextSize) -> Convertor {
509 id_alloc: { TokenIdAlloc { map: TokenMap::default(), global_offset, next_id: 0 } },
510 current: node.first_token(),
511 range: node.text_range(),
519 Ordinary(SyntaxToken),
520 Punch(SyntaxToken, TextSize),
524 fn token(&self) -> &SyntaxToken {
526 SynToken::Ordinary(it) => it,
527 SynToken::Punch(it, _) => it,
532 impl SrcToken for SynToken {
533 fn kind(&self) -> SyntaxKind {
536 fn to_char(&self) -> Option<char> {
538 SynToken::Ordinary(_) => None,
539 SynToken::Punch(it, i) => it.text().chars().nth((*i).into()),
542 fn to_text(&self) -> SmolStr {
543 self.token().text().into()
547 impl TokenConvertor for Convertor {
548 type Token = SynToken;
549 fn convert_doc_comment(&self, token: &Self::Token) -> Option<Vec<tt::TokenTree>> {
550 convert_doc_comment(token.token())
553 fn bump(&mut self) -> Option<(Self::Token, TextRange)> {
554 if let Some((punct, offset)) = self.punct_offset.clone() {
555 if usize::from(offset) + 1 < punct.text().len() {
556 let offset = offset + TextSize::of('.');
557 let range = punct.text_range();
558 self.punct_offset = Some((punct.clone(), offset));
559 let range = TextRange::at(range.start() + offset, TextSize::of('.'));
560 return Some((SynToken::Punch(punct, offset), range));
564 let curr = self.current.clone()?;
565 if !&self.range.contains_range(curr.text_range()) {
568 self.current = curr.next_token();
570 let token = if curr.kind().is_punct() {
571 let range = curr.text_range();
572 let range = TextRange::at(range.start(), TextSize::of('.'));
573 self.punct_offset = Some((curr.clone(), 0.into()));
574 (SynToken::Punch(curr, 0.into()), range)
576 self.punct_offset = None;
577 let range = curr.text_range();
578 (SynToken::Ordinary(curr), range)
584 fn peek(&self) -> Option<Self::Token> {
585 if let Some((punct, mut offset)) = self.punct_offset.clone() {
586 offset = offset + TextSize::of('.');
587 if usize::from(offset) < punct.text().len() {
588 return Some(SynToken::Punch(punct, offset));
592 let curr = self.current.clone()?;
593 if !self.range.contains_range(curr.text_range()) {
597 let token = if curr.kind().is_punct() {
598 SynToken::Punch(curr, 0.into())
600 SynToken::Ordinary(curr)
605 fn id_alloc(&mut self) -> &mut TokenIdAlloc {
610 struct TtTreeSink<'a> {
613 open_delims: FxHashMap<tt::TokenId, TextSize>,
615 inner: SyntaxTreeBuilder,
619 // Use for detect ill-form tree which is not single root
620 roots: smallvec::SmallVec<[usize; 1]>,
623 impl<'a> TtTreeSink<'a> {
624 fn new(cursor: Cursor<'a>) -> Self {
628 open_delims: FxHashMap::default(),
630 inner: SyntaxTreeBuilder::default(),
631 roots: smallvec::SmallVec::new(),
632 token_map: TokenMap::default(),
636 fn finish(mut self) -> (Parse<SyntaxNode>, TokenMap) {
637 self.token_map.entries.shrink_to_fit();
638 (self.inner.finish(), self.token_map)
642 fn delim_to_str(d: Option<tt::DelimiterKind>, closing: bool) -> &'static str {
643 let texts = match d {
644 Some(tt::DelimiterKind::Parenthesis) => "()",
645 Some(tt::DelimiterKind::Brace) => "{}",
646 Some(tt::DelimiterKind::Bracket) => "[]",
650 let idx = closing as usize;
651 &texts[idx..texts.len() - (1 - idx)]
654 impl<'a> TreeSink for TtTreeSink<'a> {
655 fn token(&mut self, kind: SyntaxKind, mut n_tokens: u8) {
656 if kind == L_DOLLAR || kind == R_DOLLAR {
657 self.cursor = self.cursor.bump_subtree();
660 if kind == LIFETIME_IDENT {
664 let mut last = self.cursor;
665 for _ in 0..n_tokens {
666 let tmp_str: SmolStr;
667 if self.cursor.eof() {
671 let text: &str = match self.cursor.token_tree() {
672 Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
673 // Mark the range if needed
674 let (text, id) = match leaf {
675 tt::Leaf::Ident(ident) => (&ident.text, ident.id),
676 tt::Leaf::Punct(punct) => {
677 assert!(punct.char.is_ascii());
678 let char = &(punct.char as u8);
679 tmp_str = SmolStr::new_inline(
680 std::str::from_utf8(std::slice::from_ref(char)).unwrap(),
684 tt::Leaf::Literal(lit) => (&lit.text, lit.id),
686 let range = TextRange::at(self.text_pos, TextSize::of(text.as_str()));
687 self.token_map.insert(id, range);
688 self.cursor = self.cursor.bump();
691 Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) => {
692 self.cursor = self.cursor.subtree().unwrap();
693 if let Some(id) = subtree.delimiter.map(|it| it.id) {
694 self.open_delims.insert(id, self.text_pos);
696 delim_to_str(subtree.delimiter_kind(), false)
699 if let Some(parent) = self.cursor.end() {
700 self.cursor = self.cursor.bump();
701 if let Some(id) = parent.delimiter.map(|it| it.id) {
702 if let Some(open_delim) = self.open_delims.get(&id) {
703 let open_range = TextRange::at(*open_delim, TextSize::of('('));
704 let close_range = TextRange::at(self.text_pos, TextSize::of('('));
705 self.token_map.insert_delim(id, open_range, close_range);
708 delim_to_str(parent.delimiter_kind(), true)
715 self.text_pos += TextSize::of(text);
718 self.inner.token(kind, self.buf.as_str());
720 // Add whitespace between adjoint puncts
721 let next = last.bump();
723 Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(curr), _)),
724 Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(_), _)),
725 ) = (last.token_tree(), next.token_tree())
727 // Note: We always assume the semi-colon would be the last token in
728 // other parts of RA such that we don't add whitespace here.
729 if curr.spacing == tt::Spacing::Alone && curr.char != ';' {
730 self.inner.token(WHITESPACE, " ");
731 self.text_pos += TextSize::of(' ');
736 fn start_node(&mut self, kind: SyntaxKind) {
737 self.inner.start_node(kind);
739 match self.roots.last_mut() {
740 None | Some(0) => self.roots.push(1),
741 Some(ref mut n) => **n += 1,
745 fn finish_node(&mut self) {
746 self.inner.finish_node();
747 *self.roots.last_mut().unwrap() -= 1;
750 fn error(&mut self, error: ParseError) {
751 self.inner.error(error, self.text_pos)
758 use crate::tests::parse_macro;
759 use parser::TokenSource;
761 algo::{insert_children, InsertPosition},
766 fn convert_tt_token_source() {
767 let expansion = parse_macro(
769 macro_rules! literals {
781 .expand_tt("literals!(foo);");
782 let tts = &[expansion.into()];
783 let buffer = tt::buffer::TokenBuffer::from_tokens(tts);
784 let mut tt_src = SubtreeTokenSource::new(&buffer);
785 let mut tokens = vec![];
786 while tt_src.current().kind != EOF {
787 tokens.push((tt_src.current().kind, tt_src.text()));
792 // [let] [a] [=] ['c'] [;]
793 assert_eq!(tokens[2 + 3].1, "'c'");
794 assert_eq!(tokens[2 + 3].0, CHAR);
795 // [let] [c] [=] [1000] [;]
796 assert_eq!(tokens[2 + 5 + 3].1, "1000");
797 assert_eq!(tokens[2 + 5 + 3].0, INT_NUMBER);
798 // [let] [f] [=] [12E+99_f64] [;]
799 assert_eq!(tokens[2 + 10 + 3].1, "12E+99_f64");
800 assert_eq!(tokens[2 + 10 + 3].0, FLOAT_NUMBER);
802 // [let] [s] [=] ["rust1"] [;]
803 assert_eq!(tokens[2 + 15 + 3].1, "\"rust1\"");
804 assert_eq!(tokens[2 + 15 + 3].0, STRING);
808 fn stmts_token_trees_to_expr_is_err() {
809 let expansion = parse_macro(
821 .expand_tt("stmts!();");
822 assert!(token_tree_to_syntax_node(&expansion, FragmentKind::Expr).is_err());
826 fn test_token_tree_last_child_is_white_space() {
827 let source_file = ast::SourceFile::parse("f!({} );").ok().unwrap();
828 let macro_call = source_file.syntax().descendants().find_map(ast::MacroCall::cast).unwrap();
829 let token_tree = macro_call.token_tree().unwrap();
831 // Token Tree now is :
841 token_tree.syntax().descendants_with_tokens().find(|it| it.kind() == T!['}']).unwrap();
842 let space = token_tree
844 .descendants_with_tokens()
845 .find(|it| it.kind() == SyntaxKind::WHITESPACE)
848 // reorder th white space, such that the white is inside the inner token-tree.
849 let token_tree = insert_children(
850 &rbrace.parent().unwrap(),
851 InsertPosition::Last,
852 std::iter::once(space),
855 // Token Tree now is :
860 let token_tree = ast::TokenTree::cast(token_tree).unwrap();
861 let tt = ast_to_token_tree(&token_tree).unwrap().0;
863 assert_eq!(tt.delimiter_kind(), Some(tt::DelimiterKind::Brace));
867 fn test_token_tree_multi_char_punct() {
868 let source_file = ast::SourceFile::parse("struct Foo { a: x::Y }").ok().unwrap();
869 let struct_def = source_file.syntax().descendants().find_map(ast::Struct::cast).unwrap();
870 let tt = ast_to_token_tree(&struct_def).unwrap().0;
871 token_tree_to_syntax_node(&tt, FragmentKind::Item).unwrap();