Relocate TokenStreamExt2 into crate::ext

Author: dtolnay

src/buffer.rs

@@ -5,7 +5,7 @@
 // Syn, and caution should be used when editing it. The public-facing interface
 // is 100% safe but the implementation is fragile internally.
 
-use crate::error::TokenStreamExt2 as _;
+use crate::ext::TokenStreamExt2 as _;
 use crate::Lifetime;
 use proc_macro2::extra::DelimSpan;
 use proc_macro2::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};

src/error.rs

@@ -1,14 +1,15 @@
 #[cfg(feature = "parsing")]
 use crate::buffer::Cursor;
+use crate::ext::TokenStreamExt2 as _;
 use crate::thread::ThreadBound;
 use proc_macro2::{
     Delimiter, Group, Ident, LexError, Literal, Punct, Spacing, Span, TokenStream, TokenTree,
 };
 #[cfg(feature = "printing")]
 use quote::ToTokens;
 use std::fmt::{self, Debug, Display};
+use std::slice;
 use std::vec;
-use std::{iter, slice};
 
 /// The result of a Syn parser.
 pub type Result<T> = std::result::Result<T, Error>;
@@ -312,16 +313,6 @@ impl ErrorMessage {
     }
 }
 
-pub(crate) trait TokenStreamExt2 {
-    fn append(&mut self, token: TokenTree);
-}
-
-impl TokenStreamExt2 for TokenStream {
-    fn append(&mut self, token: TokenTree) {
-        self.extend(iter::once(token));
-    }
-}
-
 #[cfg(feature = "parsing")]
 pub(crate) fn new_at<T: Display>(scope: Span, cursor: Cursor, message: T) -> Error {
     if cursor.eof() {

src/ext.rs

@@ -12,7 +12,8 @@ use crate::parse::Peek;
 use crate::sealed::lookahead;
 #[cfg(feature = "parsing")]
 use crate::token::CustomToken;
-use proc_macro2::Ident;
+use proc_macro2::{Ident, TokenStream, TokenTree};
+use std::iter;
 
 /// Additional methods for `Ident` not provided by proc-macro2 or libproc_macro.
 ///
@@ -131,6 +132,16 @@ impl CustomToken for private::IdentAny {
 #[cfg(feature = "parsing")]
 impl lookahead::Sealed for private::PeekFn {}
 
+pub(crate) trait TokenStreamExt2 {
+    fn append(&mut self, token: TokenTree);
+}
+
+impl TokenStreamExt2 for TokenStream {
+    fn append(&mut self, token: TokenTree) {
+        self.extend(iter::once(token));
+    }
+}
+
 mod private {
     use proc_macro2::Ident;
 

src/lit.rs

@@ -215,7 +215,7 @@ impl LitStr {
 
         // Token stream with every span replaced by the given one.
         fn respan_token_stream(stream: TokenStream, span: Span) -> TokenStream {
-            use crate::error::TokenStreamExt2 as _;
+            use crate::ext::TokenStreamExt2 as _;
 
             let mut tokens = TokenStream::new();
             for token in stream {

src/verbatim.rs

@@ -1,4 +1,4 @@
-use crate::error::TokenStreamExt2 as _;
+use crate::ext::TokenStreamExt2 as _;
 use crate::parse::ParseStream;
 use proc_macro2::{Delimiter, TokenStream};
 use std::cmp::Ordering;