Merge pull request #334 from dtolnay/sizehint

Expose size_hint() for TokenStream's iterator
dtolnay · Jul 25, 2022 · 6a35155 · 6a35155
2 parents 6ed82b0 + 25a20e0
commit 6a35155
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diff --git a/src/lib.rs b/src/lib.rs
@@ -1290,6 +1290,10 @@ pub mod token_stream {
         fn next(&mut self) -> Option<TokenTree> {
             self.inner.next()
         }
+
+        fn size_hint(&self) -> (usize, Option<usize>) {
+            self.inner.size_hint()
+        }
     }
 
     impl Debug for IntoIter {

diff --git a/tests/test.rs b/tests/test.rs
@@ -547,6 +547,13 @@ fn default_tokenstream_is_empty() {
     assert!(default_token_stream.is_empty());
 }
 
+#[test]
+fn tokenstream_size_hint() {
+    let tokens = "a b (c d) e".parse::<TokenStream>().unwrap();
+
+    assert_eq!(tokens.into_iter().size_hint(), (4, Some(4)));
+}
+
 #[test]
 fn tuple_indexing() {
     // This behavior may change depending on https://github.com/rust-lang/rust/pull/71322