Remove lifetime parameter from syntax::tokenstream::Cursor.

Author: jseyfried

src/libproc_macro_plugin/qquote.rs

@@ -51,7 +51,7 @@ macro_rules! quote_tree {
 fn delimit(delim: token::DelimToken, stream: TokenStream) -> TokenStream {
     TokenTree::Delimited(DUMMY_SP, Rc::new(Delimited {
         delim: delim,
-        tts: stream.trees().cloned().collect(),
+        tts: stream.into_trees().collect(),
     })).into()
 }
 
@@ -75,21 +75,21 @@ impl Quote for TokenStream {
             return quote!(::syntax::tokenstream::TokenStream::empty());
         }
 
-        struct Quote<'a>(tokenstream::Cursor<'a>);
+        struct Quote(tokenstream::Cursor);
 
-        impl<'a> Iterator for Quote<'a> {
+        impl Iterator for Quote {
             type Item = TokenStream;
 
             fn next(&mut self) -> Option<TokenStream> {
                 let is_unquote = match self.0.peek() {
-                    Some(&TokenTree::Token(_, Token::Ident(ident))) if ident.name == "unquote" => {
+                    Some(TokenTree::Token(_, Token::Ident(ident))) if ident.name == "unquote" => {
                         self.0.next();
                         true
                     }
                     _ => false,
                 };
 
-                self.0.next().cloned().map(|tree| {
+                self.0.next().map(|tree| {
                     let quoted_tree = if is_unquote { tree.into() } else { tree.quote() };
                     quote!(::syntax::tokenstream::TokenStream::from((unquote quoted_tree)),)
                 })
@@ -104,7 +104,7 @@ impl Quote for TokenStream {
 impl Quote for Vec<TokenTree> {
     fn quote(&self) -> TokenStream {
         let stream = self.iter().cloned().collect::<TokenStream>();
-        quote!((quote stream).trees().cloned().collect::<::std::vec::Vec<_> >())
+        quote!((quote stream).into_trees().collect::<::std::vec::Vec<_> >())
     }
 }
 

src/libsyntax/ext/expand.rs

@@ -647,7 +647,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
     fn parse_expansion(&mut self, toks: TokenStream, kind: ExpansionKind, name: Name, span: Span)
                        -> Expansion {
-        let mut parser = self.cx.new_parser_from_tts(&toks.trees().cloned().collect::<Vec<_>>());
+        let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
         let expansion = match parser.parse_expansion(kind, false) {
             Ok(expansion) => expansion,
             Err(mut err) => {

src/libsyntax/parse/mod.rs

@@ -192,7 +192,7 @@ pub fn new_parser_from_tts<'a>(sess: &'a ParseSess, tts: Vec<tokenstream::TokenT
 }
 
 pub fn new_parser_from_ts<'a>(sess: &'a ParseSess, ts: tokenstream::TokenStream) -> Parser<'a> {
-    tts_to_parser(sess, ts.trees().cloned().collect())
+    tts_to_parser(sess, ts.into_trees().collect())
 }
 
 

src/libsyntax/tokenstream.rs

@@ -35,7 +35,7 @@ use serialize::{Decoder, Decodable, Encoder, Encodable};
 use symbol::Symbol;
 use util::RcSlice;
 
-use std::{fmt, iter};
+use std::{fmt, iter, mem};
 use std::rc::Rc;
 
 /// A delimited sequence of token trees
@@ -338,87 +338,93 @@ impl TokenStream {
         TokenStream { kind: TokenStreamKind::Stream(RcSlice::new(vec)) }
     }
 
-    pub fn trees<'a>(&'a self) -> Cursor {
+    pub fn trees(&self) -> Cursor {
+        self.clone().into_trees()
+    }
+
+    pub fn into_trees(self) -> Cursor {
         Cursor::new(self)
     }
 
     /// Compares two TokenStreams, checking equality without regarding span information.
     pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
         for (t1, t2) in self.trees().zip(other.trees()) {
-            if !t1.eq_unspanned(t2) {
+            if !t1.eq_unspanned(&t2) {
                 return false;
             }
         }
         true
     }
 }
 
-pub struct Cursor<'a> {
-    current_frame: CursorFrame<'a>,
-    stack: Vec<CursorFrame<'a>>,
+pub struct Cursor {
+    current_frame: CursorFrame,
+    stack: Vec<CursorFrame>,
 }
 
-impl<'a> Iterator for Cursor<'a> {
-    type Item = &'a TokenTree;
+impl Iterator for Cursor {
+    type Item = TokenTree;
 
-    fn next(&mut self) -> Option<&'a TokenTree> {
+    fn next(&mut self) -> Option<TokenTree> {
         let tree = self.peek();
         self.current_frame = self.stack.pop().unwrap_or(CursorFrame::Empty);
         tree
     }
 }
 
-enum CursorFrame<'a> {
+enum CursorFrame {
     Empty,
-    Tree(&'a TokenTree),
-    Stream(&'a RcSlice<TokenStream>, usize),
+    Tree(TokenTree),
+    Stream(RcSlice<TokenStream>, usize),
 }
 
-impl<'a> CursorFrame<'a> {
-    fn new(stream: &'a TokenStream) -> Self {
+impl CursorFrame {
+    fn new(stream: TokenStream) -> Self {
         match stream.kind {
             TokenStreamKind::Empty => CursorFrame::Empty,
-            TokenStreamKind::Tree(ref tree) => CursorFrame::Tree(tree),
-            TokenStreamKind::Stream(ref stream) => CursorFrame::Stream(stream, 0),
+            TokenStreamKind::Tree(tree) => CursorFrame::Tree(tree),
+            TokenStreamKind::Stream(stream) => CursorFrame::Stream(stream, 0),
         }
     }
 }
 
-impl<'a> Cursor<'a> {
-    fn new(stream: &'a TokenStream) -> Self {
+impl Cursor {
+    fn new(stream: TokenStream) -> Self {
         Cursor {
             current_frame: CursorFrame::new(stream),
             stack: Vec::new(),
         }
     }
 
-    pub fn peek(&mut self) -> Option<&'a TokenTree> {
-        while let CursorFrame::Stream(stream, index) = self.current_frame {
+    pub fn peek(&mut self) -> Option<TokenTree> {
+        while let CursorFrame::Stream(stream, index) =
+                mem::replace(&mut self.current_frame, CursorFrame::Empty) {
             self.current_frame = if index == stream.len() {
                 self.stack.pop().unwrap_or(CursorFrame::Empty)
             } else {
+                let frame = CursorFrame::new(stream[index].clone());
                 self.stack.push(CursorFrame::Stream(stream, index + 1));
-                CursorFrame::new(&stream[index])
+                frame
             };
         }
 
         match self.current_frame {
             CursorFrame::Empty => None,
-            CursorFrame::Tree(tree) => Some(tree),
+            CursorFrame::Tree(ref tree) => Some(tree.clone()),
             CursorFrame::Stream(..) => unreachable!(),
         }
     }
 }
 
 impl fmt::Display for TokenStream {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str(&pprust::tts_to_string(&self.trees().cloned().collect::<Vec<_>>()))
+        f.write_str(&pprust::tts_to_string(&self.trees().collect::<Vec<_>>()))
     }
 }
 
 impl Encodable for TokenStream {
     fn encode<E: Encoder>(&self, encoder: &mut E) -> Result<(), E::Error> {
-        self.trees().cloned().collect::<Vec<_>>().encode(encoder)
+        self.trees().collect::<Vec<_>>().encode(encoder)
     }
 }
 
@@ -464,14 +470,14 @@ mod tests {
     fn test_from_to_bijection() {
         let test_start = string_to_tts("foo::bar(baz)".to_string());
         let ts = test_start.iter().cloned().collect::<TokenStream>();
-        let test_end: Vec<TokenTree> = ts.trees().cloned().collect();
+        let test_end: Vec<TokenTree> = ts.trees().collect();
         assert_eq!(test_start, test_end)
     }
 
     #[test]
     fn test_to_from_bijection() {
         let test_start = string_to_ts("foo::bar(baz)");
-        let test_end = test_start.trees().cloned().collect();
+        let test_end = test_start.trees().collect();
         assert_eq!(test_start, test_end)
     }