Rename RefTokenTreeCursor.

Because `TokenStreamIter` is a much better name for a `TokenStream`
iterator. Also rename the `TokenStream::trees` method as
`TokenStream::iter`, and some local variables.

Author: nnethercote

compiler/rustc_ast/src/attr/mod.rs

@@ -366,22 +366,22 @@ impl MetaItem {
         }
     }
 
-    fn from_tokens<'a, I>(tokens: &mut iter::Peekable<I>) -> Option<MetaItem>
+    fn from_tokens<'a, I>(iter: &mut iter::Peekable<I>) -> Option<MetaItem>
     where
         I: Iterator<Item = &'a TokenTree>,
     {
         // FIXME: Share code with `parse_path`.
-        let tt = tokens.next().map(|tt| TokenTree::uninterpolate(tt));
+        let tt = iter.next().map(|tt| TokenTree::uninterpolate(tt));
         let path = match tt.as_deref() {
             Some(&TokenTree::Token(
                 Token { kind: ref kind @ (token::Ident(..) | token::PathSep), span },
                 _,
             )) => 'arm: {
                 let mut segments = if let &token::Ident(name, _) = kind {
                     if let Some(TokenTree::Token(Token { kind: token::PathSep, .. }, _)) =
-                        tokens.peek()
+                        iter.peek()
                     {
-                        tokens.next();
+                        iter.next();
                         thin_vec![PathSegment::from_ident(Ident::new(name, span))]
                     } else {
                         break 'arm Path::from_ident(Ident::new(name, span));
@@ -391,16 +391,16 @@ impl MetaItem {
                 };
                 loop {
                     if let Some(&TokenTree::Token(Token { kind: token::Ident(name, _), span }, _)) =
-                        tokens.next().map(|tt| TokenTree::uninterpolate(tt)).as_deref()
+                        iter.next().map(|tt| TokenTree::uninterpolate(tt)).as_deref()
                     {
                         segments.push(PathSegment::from_ident(Ident::new(name, span)));
                     } else {
                         return None;
                     }
                     if let Some(TokenTree::Token(Token { kind: token::PathSep, .. }, _)) =
-                        tokens.peek()
+                        iter.peek()
                     {
-                        tokens.next();
+                        iter.next();
                     } else {
                         break;
                     }
@@ -421,8 +421,8 @@ impl MetaItem {
             }
             _ => return None,
         };
-        let list_closing_paren_pos = tokens.peek().map(|tt| tt.span().hi());
-        let kind = MetaItemKind::from_tokens(tokens)?;
+        let list_closing_paren_pos = iter.peek().map(|tt| tt.span().hi());
+        let kind = MetaItemKind::from_tokens(iter)?;
         let hi = match &kind {
             MetaItemKind::NameValue(lit) => lit.span.hi(),
             MetaItemKind::List(..) => list_closing_paren_pos.unwrap_or(path.span.hi()),
@@ -439,12 +439,12 @@ impl MetaItem {
 impl MetaItemKind {
     // public because it can be called in the hir
     pub fn list_from_tokens(tokens: TokenStream) -> Option<ThinVec<MetaItemInner>> {
-        let mut tokens = tokens.trees().peekable();
+        let mut iter = tokens.iter().peekable();
         let mut result = ThinVec::new();
-        while tokens.peek().is_some() {
-            let item = MetaItemInner::from_tokens(&mut tokens)?;
+        while iter.peek().is_some() {
+            let item = MetaItemInner::from_tokens(&mut iter)?;
             result.push(item);
-            match tokens.next() {
+            match iter.next() {
                 None | Some(TokenTree::Token(Token { kind: token::Comma, .. }, _)) => {}
                 _ => return None,
             }
@@ -453,11 +453,11 @@ impl MetaItemKind {
     }
 
     fn name_value_from_tokens<'a>(
-        tokens: &mut impl Iterator<Item = &'a TokenTree>,
+        iter: &mut impl Iterator<Item = &'a TokenTree>,
     ) -> Option<MetaItemKind> {
-        match tokens.next() {
+        match iter.next() {
             Some(TokenTree::Delimited(.., Delimiter::Invisible(_), inner_tokens)) => {
-                MetaItemKind::name_value_from_tokens(&mut inner_tokens.trees())
+                MetaItemKind::name_value_from_tokens(&mut inner_tokens.iter())
             }
             Some(TokenTree::Token(token, _)) => {
                 MetaItemLit::from_token(token).map(MetaItemKind::NameValue)
@@ -467,18 +467,18 @@ impl MetaItemKind {
     }
 
     fn from_tokens<'a>(
-        tokens: &mut iter::Peekable<impl Iterator<Item = &'a TokenTree>>,
+        iter: &mut iter::Peekable<impl Iterator<Item = &'a TokenTree>>,
     ) -> Option<MetaItemKind> {
-        match tokens.peek() {
+        match iter.peek() {
             Some(TokenTree::Delimited(.., Delimiter::Parenthesis, inner_tokens)) => {
                 let inner_tokens = inner_tokens.clone();
-                tokens.next();
+                iter.next();
                 MetaItemKind::list_from_tokens(inner_tokens).map(MetaItemKind::List)
             }
             Some(TokenTree::Delimited(..)) => None,
             Some(TokenTree::Token(Token { kind: token::Eq, .. }, _)) => {
-                tokens.next();
-                MetaItemKind::name_value_from_tokens(tokens)
+                iter.next();
+                MetaItemKind::name_value_from_tokens(iter)
             }
             _ => Some(MetaItemKind::Word),
         }
@@ -594,22 +594,22 @@ impl MetaItemInner {
         self.meta_item().is_some()
     }
 
-    fn from_tokens<'a, I>(tokens: &mut iter::Peekable<I>) -> Option<MetaItemInner>
+    fn from_tokens<'a, I>(iter: &mut iter::Peekable<I>) -> Option<MetaItemInner>
     where
         I: Iterator<Item = &'a TokenTree>,
     {
-        match tokens.peek() {
+        match iter.peek() {
             Some(TokenTree::Token(token, _)) if let Some(lit) = MetaItemLit::from_token(token) => {
-                tokens.next();
+                iter.next();
                 return Some(MetaItemInner::Lit(lit));
             }
             Some(TokenTree::Delimited(.., Delimiter::Invisible(_), inner_tokens)) => {
-                tokens.next();
-                return MetaItemInner::from_tokens(&mut inner_tokens.trees().peekable());
+                iter.next();
+                return MetaItemInner::from_tokens(&mut inner_tokens.iter().peekable());
             }
             _ => {}
         }
-        MetaItem::from_tokens(tokens).map(MetaItemInner::MetaItem)
+        MetaItem::from_tokens(iter).map(MetaItemInner::MetaItem)
     }
 }
 

compiler/rustc_ast/src/tokenstream.rs

@@ -99,7 +99,7 @@ where
     CTX: crate::HashStableContext,
 {
     fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        for sub_tt in self.trees() {
+        for sub_tt in self.iter() {
             sub_tt.hash_stable(hcx, hasher);
         }
     }
@@ -406,7 +406,7 @@ impl Eq for TokenStream {}
 
 impl PartialEq<TokenStream> for TokenStream {
     fn eq(&self, other: &TokenStream) -> bool {
-        self.trees().eq(other.trees())
+        self.iter().eq(other.iter())
     }
 }
 
@@ -423,8 +423,8 @@ impl TokenStream {
         self.0.len()
     }
 
-    pub fn trees(&self) -> RefTokenTreeCursor<'_> {
-        RefTokenTreeCursor::new(self)
+    pub fn iter(&self) -> TokenStreamIter<'_> {
+        TokenStreamIter::new(self)
     }
 
     pub fn into_trees(self) -> TokenTreeCursor {
@@ -433,14 +433,14 @@ impl TokenStream {
 
     /// Compares two `TokenStream`s, checking equality without regarding span information.
     pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
-        let mut t1 = self.trees();
-        let mut t2 = other.trees();
-        for (t1, t2) in iter::zip(&mut t1, &mut t2) {
-            if !t1.eq_unspanned(t2) {
+        let mut iter1 = self.iter();
+        let mut iter2 = other.iter();
+        for (tt1, tt2) in iter::zip(&mut iter1, &mut iter2) {
+            if !tt1.eq_unspanned(tt2) {
                 return false;
             }
         }
-        t1.next().is_none() && t2.next().is_none()
+        iter1.next().is_none() && iter2.next().is_none()
     }
 
     /// Create a token stream containing a single token with alone spacing. The
@@ -509,7 +509,7 @@ impl TokenStream {
     #[must_use]
     pub fn flattened(&self) -> TokenStream {
         fn can_skip(stream: &TokenStream) -> bool {
-            stream.trees().all(|tree| match tree {
+            stream.iter().all(|tree| match tree {
                 TokenTree::Token(token, _) => !matches!(
                     token.kind,
                     token::NtIdent(..) | token::NtLifetime(..) | token::Interpolated(..)
@@ -522,7 +522,7 @@ impl TokenStream {
             return self.clone();
         }
 
-        self.trees().map(|tree| TokenStream::flatten_token_tree(tree)).collect()
+        self.iter().map(|tree| TokenStream::flatten_token_tree(tree)).collect()
     }
 
     // If `vec` is not empty, try to glue `tt` onto its last token. The return
@@ -665,25 +665,23 @@ impl TokenStream {
     }
 }
 
-/// By-reference iterator over a [`TokenStream`], that produces `&TokenTree`
-/// items.
 #[derive(Clone)]
-pub struct RefTokenTreeCursor<'t> {
+pub struct TokenStreamIter<'t> {
     stream: &'t TokenStream,
     index: usize,
 }
 
-impl<'t> RefTokenTreeCursor<'t> {
+impl<'t> TokenStreamIter<'t> {
     fn new(stream: &'t TokenStream) -> Self {
-        RefTokenTreeCursor { stream, index: 0 }
+        TokenStreamIter { stream, index: 0 }
     }
 
     pub fn peek(&self) -> Option<&TokenTree> {
         self.stream.0.get(self.index)
     }
 }
 
-impl<'t> Iterator for RefTokenTreeCursor<'t> {
+impl<'t> Iterator for TokenStreamIter<'t> {
     type Item = &'t TokenTree;
 
     fn next(&mut self) -> Option<&'t TokenTree> {
@@ -701,7 +699,7 @@ impl<'t> Iterator for RefTokenTreeCursor<'t> {
 /// return `&T` from `next`; the need for an explicit lifetime in the `Item`
 /// associated type gets in the way. Instead, use `next_ref` (which doesn't
 /// involve associated types) for getting individual elements, or
-/// `RefTokenTreeCursor` if you really want an `Iterator`, e.g. in a `for`
+/// `TokenStreamIter` if you really want an `Iterator`, e.g. in a `for`
 /// loop.
 #[derive(Clone, Debug)]
 pub struct TokenTreeCursor {

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -725,7 +725,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     // E.g. we have seen cases where a proc macro can handle `a :: b` but not
     // `a::b`. See #117433 for some examples.
     fn print_tts(&mut self, tts: &TokenStream, convert_dollar_crate: bool) {
-        let mut iter = tts.trees().peekable();
+        let mut iter = tts.iter().peekable();
         while let Some(tt) = iter.next() {
             let spacing = self.print_tt(tt, convert_dollar_crate);
             if let Some(next) = iter.peek() {

compiler/rustc_builtin_macros/src/concat_idents.rs

@@ -19,7 +19,7 @@ pub(crate) fn expand_concat_idents<'cx>(
     }
 
     let mut res_str = String::new();
-    for (i, e) in tts.trees().enumerate() {
+    for (i, e) in tts.iter().enumerate() {
         if i & 1 == 1 {
             match e {
                 TokenTree::Token(Token { kind: token::Comma, .. }, _) => {}

compiler/rustc_builtin_macros/src/trace_macros.rs

@@ -10,17 +10,17 @@ pub(crate) fn expand_trace_macros(
     sp: Span,
     tt: TokenStream,
 ) -> MacroExpanderResult<'static> {
-    let mut cursor = tt.trees();
+    let mut iter = tt.iter();
     let mut err = false;
-    let value = match &cursor.next() {
+    let value = match iter.next() {
         Some(TokenTree::Token(token, _)) if token.is_keyword(kw::True) => true,
         Some(TokenTree::Token(token, _)) if token.is_keyword(kw::False) => false,
         _ => {
             err = true;
             false
         }
     };
-    err |= cursor.next().is_some();
+    err |= iter.next().is_some();
     if err {
         cx.dcx().emit_err(errors::TraceMacros { span: sp });
     } else {

compiler/rustc_expand/src/mbe/metavar_expr.rs

@@ -1,5 +1,5 @@
 use rustc_ast::token::{self, Delimiter, IdentIsRaw, Lit, Token, TokenKind};
-use rustc_ast::tokenstream::{RefTokenTreeCursor, TokenStream, TokenTree};
+use rustc_ast::tokenstream::{TokenStream, TokenStreamIter, TokenTree};
 use rustc_ast::{LitIntType, LitKind};
 use rustc_ast_pretty::pprust;
 use rustc_errors::{Applicability, PResult};
@@ -39,14 +39,14 @@ impl MetaVarExpr {
         outer_span: Span,
         psess: &'psess ParseSess,
     ) -> PResult<'psess, MetaVarExpr> {
-        let mut tts = input.trees();
-        let ident = parse_ident(&mut tts, psess, outer_span)?;
-        let Some(TokenTree::Delimited(.., Delimiter::Parenthesis, args)) = tts.next() else {
+        let mut iter = input.iter();
+        let ident = parse_ident(&mut iter, psess, outer_span)?;
+        let Some(TokenTree::Delimited(.., Delimiter::Parenthesis, args)) = iter.next() else {
             let msg = "meta-variable expression parameter must be wrapped in parentheses";
             return Err(psess.dcx().struct_span_err(ident.span, msg));
         };
-        check_trailing_token(&mut tts, psess)?;
-        let mut iter = args.trees();
+        check_trailing_token(&mut iter, psess)?;
+        let mut iter = args.iter();
         let rslt = match ident.as_str() {
             "concat" => {
                 let mut result = Vec::new();
@@ -143,7 +143,7 @@ pub(crate) enum MetaVarExprConcatElem {
 
 // Checks if there are any remaining tokens. For example, `${ignore(ident ... a b c ...)}`
 fn check_trailing_token<'psess>(
-    iter: &mut RefTokenTreeCursor<'_>,
+    iter: &mut TokenStreamIter<'_>,
     psess: &'psess ParseSess,
 ) -> PResult<'psess, ()> {
     if let Some(tt) = iter.next() {
@@ -159,7 +159,7 @@ fn check_trailing_token<'psess>(
 
 /// Parse a meta-variable `count` expression: `count(ident[, depth])`
 fn parse_count<'psess>(
-    iter: &mut RefTokenTreeCursor<'_>,
+    iter: &mut TokenStreamIter<'_>,
     psess: &'psess ParseSess,
     span: Span,
 ) -> PResult<'psess, MetaVarExpr> {
@@ -181,7 +181,7 @@ fn parse_count<'psess>(
 
 /// Parses the depth used by index(depth) and len(depth).
 fn parse_depth<'psess>(
-    iter: &mut RefTokenTreeCursor<'_>,
+    iter: &mut TokenStreamIter<'_>,
     psess: &'psess ParseSess,
     span: Span,
 ) -> PResult<'psess, usize> {
@@ -204,7 +204,7 @@ fn parse_depth<'psess>(
 
 /// Parses an generic ident
 fn parse_ident<'psess>(
-    iter: &mut RefTokenTreeCursor<'_>,
+    iter: &mut TokenStreamIter<'_>,
     psess: &'psess ParseSess,
     fallback_span: Span,
 ) -> PResult<'psess, Ident> {
@@ -236,7 +236,7 @@ fn parse_ident_from_token<'psess>(
 }
 
 fn parse_token<'psess, 't>(
-    iter: &mut RefTokenTreeCursor<'t>,
+    iter: &mut TokenStreamIter<'t>,
     psess: &'psess ParseSess,
     fallback_span: Span,
 ) -> PResult<'psess, &'t Token> {
@@ -251,7 +251,7 @@ fn parse_token<'psess, 't>(
 
 /// Tries to move the iterator forward returning `true` if there is a comma. If not, then the
 /// iterator is not modified and the result is `false`.
-fn try_eat_comma(iter: &mut RefTokenTreeCursor<'_>) -> bool {
+fn try_eat_comma(iter: &mut TokenStreamIter<'_>) -> bool {
     if let Some(TokenTree::Token(Token { kind: token::Comma, .. }, _)) = iter.peek() {
         let _ = iter.next();
         return true;
@@ -261,7 +261,7 @@ fn try_eat_comma(iter: &mut RefTokenTreeCursor<'_>) -> bool {
 
 /// Tries to move the iterator forward returning `true` if there is a dollar sign. If not, then the
 /// iterator is not modified and the result is `false`.
-fn try_eat_dollar(iter: &mut RefTokenTreeCursor<'_>) -> bool {
+fn try_eat_dollar(iter: &mut TokenStreamIter<'_>) -> bool {
     if let Some(TokenTree::Token(Token { kind: token::Dollar, .. }, _)) = iter.peek() {
         let _ = iter.next();
         return true;
@@ -271,7 +271,7 @@ fn try_eat_dollar(iter: &mut RefTokenTreeCursor<'_>) -> bool {
 
 /// Expects that the next item is a dollar sign.
 fn eat_dollar<'psess>(
-    iter: &mut RefTokenTreeCursor<'_>,
+    iter: &mut TokenStreamIter<'_>,
     psess: &'psess ParseSess,
     span: Span,
 ) -> PResult<'psess, ()> {