Update laziness.rs

6 iterators now have the `must_use` attribute so we need to update here because of the denied "unused_must_use" lint.

tests/laziness.rs

@@ -192,9 +192,9 @@ must_use_tests! {
         let _ = Panicking.combinations(2);
     }
     combinations_with_replacement {
-        Panicking.combinations_with_replacement(0);
-        Panicking.combinations_with_replacement(1);
-        Panicking.combinations_with_replacement(2);
+        let _ = Panicking.combinations_with_replacement(0);
+        let _ = Panicking.combinations_with_replacement(1);
+        let _ = Panicking.combinations_with_replacement(2);
     }
     permutations {
         let _ = Panicking.permutations(0);
@@ -217,7 +217,7 @@ must_use_tests! {
         let _ = Panicking.update(|n| *n += 1);
     }
     multipeek {
-        Panicking.multipeek();
+        let _ = Panicking.multipeek();
     }
     // Not iterator themselves but still lazy.
     into_grouping_map {
@@ -247,16 +247,16 @@ must_use_tests! {
         let _ = itertools::multizip((Panicking, Panicking));
     }
     put_back {
-        itertools::put_back(Panicking);
-        itertools::put_back(Panicking).with_value(15);
+        let _ = itertools::put_back(Panicking);
+        let _ = itertools::put_back(Panicking).with_value(15);
     }
     peek_nth {
-        itertools::peek_nth(Panicking);
+        let _ = itertools::peek_nth(Panicking);
     }
     put_back_n {
-        itertools::put_back_n(Panicking);
+        let _ = itertools::put_back_n(Panicking);
     }
     rciter {
-        itertools::rciter(Panicking);
+        let _ = itertools::rciter(Panicking);
     }
 }