diff options
| -rw-r--r-- | src/libcollections/vec.rs | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs index 50ad4856747..8bed02c79e0 100644 --- a/src/libcollections/vec.rs +++ b/src/libcollections/vec.rs @@ -1578,7 +1578,13 @@ impl<I> IsTrustedLen for I where I: Iterator { } impl<I> IsTrustedLen for I where I: TrustedLen { fn trusted_len(&self) -> Option<usize> { - self.size_hint().1 + let (low, high) = self.size_hint(); + if let Some(high_value) = high { + debug_assert_eq!(low, high_value, + "TrustedLen iterator's size hint is not exact: {:?}", + (low, high)); + } + high } } |