diff --git a/src/rank/mod.rs b/src/rank/mod.rs
index 2023cb266..5416ca882 100644
--- a/src/rank/mod.rs
+++ b/src/rank/mod.rs
@@ -2,7 +2,6 @@ pub mod criterion;
 mod query_builder;
 mod distinct_map;
 
-use std::iter::FusedIterator;
 use std::slice::Windows;
 
 use sdset::SetBuf;
@@ -83,10 +82,9 @@ pub struct QueryIndexGroups<'a, 'b> {
     windows: Windows<'b, usize>,
 }
 
-impl<'a> Iterator for QueryIndexGroups<'a, '_> {
+impl<'a, 'b> Iterator for QueryIndexGroups<'a, 'b> {
     type Item = &'a [Match];
 
-    #[inline]
     fn next(&mut self) -> Option<Self::Item> {
         self.windows.next().map(|range| {
             match *range {
@@ -95,56 +93,10 @@ impl<'a> Iterator for QueryIndexGroups<'a, '_> {
             }
         })
     }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.windows.size_hint()
-    }
-
-    #[inline]
-    fn count(self) -> usize {
-        self.len()
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<Self::Item> {
-        self.windows.nth(n).map(|range| {
-            match *range {
-                [left, right] => &self.matches[left..right],
-                _             => unreachable!(),
-            }
-        })
-    }
-
-    #[inline]
-    fn last(self) -> Option<Self::Item> {
-        let (matches, windows) = (self.matches, self.windows);
-        windows.last().map(|range| {
-            match *range {
-                [left, right] => &matches[left..right],
-                _             => unreachable!(),
-            }
-        })
-    }
 }
 
-impl ExactSizeIterator for QueryIndexGroups<'_, '_> {
-    #[inline]
-    fn len(&self) -> usize {
-        self.windows.len()
-    }
-}
-
-impl FusedIterator for QueryIndexGroups<'_, '_> { }
-
-impl DoubleEndedIterator for QueryIndexGroups<'_, '_> {
-    #[inline]
-    fn next_back(&mut self) -> Option<Self::Item> {
-        self.windows.next_back().map(|range| {
-            match *range {
-                [left, right] => &self.matches[left..right],
-                _             => unreachable!(),
-            }
-        })
-    }
-}
+// impl ExactSizeIterator for QueryIndexGroups<'_, '_> {
+//     fn len(&self) -> usize {
+//         self.windows.len() // FIXME (+1) ?
+//     }
+// }