diff --git a/compiler/collections/src/vec_map.rs b/compiler/collections/src/vec_map.rs
index 33ef76d4c0..8a38fcdb7b 100644
--- a/compiler/collections/src/vec_map.rs
+++ b/compiler/collections/src/vec_map.rs
@@ -13,6 +13,13 @@ impl<K, V> Default for VecMap<K, V> {
     }
 }
 
+impl<K, V> VecMap<K, V> {
+    pub fn len(&self) -> usize {
+        debug_assert_eq!(self.keys.len(), self.values.len());
+        self.keys.len()
+    }
+}
+
 impl<K: PartialEq, V> VecMap<K, V> {
     pub fn with_capacity(capacity: usize) -> Self {
         Self {
@@ -21,11 +28,6 @@ impl<K: PartialEq, V> VecMap<K, V> {
         }
     }
 
-    pub fn len(&self) -> usize {
-        debug_assert_eq!(self.keys.len(), self.values.len());
-        self.keys.len()
-    }
-
     pub fn is_empty(&self) -> bool {
         debug_assert_eq!(self.keys.len(), self.values.len());
         self.keys.is_empty()
@@ -95,10 +97,6 @@ impl<K: PartialEq, V> VecMap<K, V> {
         self.keys.iter().zip(self.values.iter())
     }
 
-    pub fn into_iter(self) -> impl ExactSizeIterator<Item = (K, V)> {
-        self.keys.into_iter().zip(self.values.into_iter())
-    }
-
     pub fn keys(&self) -> impl ExactSizeIterator<Item = &K> {
         self.keys.iter()
     }
@@ -157,6 +155,7 @@ impl<K, V> IntoIterator for VecMap<K, V> {
 
     fn into_iter(self) -> Self::IntoIter {
         IntoIter {
+            len: self.len(),
             keys: self.keys.into_iter(),
             values: self.values.into_iter(),
         }
@@ -164,6 +163,7 @@ impl<K, V> IntoIterator for VecMap<K, V> {
 }
 
 pub struct IntoIter<K, V> {
+    len: usize,
     keys: std::vec::IntoIter<K>,
     values: std::vec::IntoIter<V>,
 }
@@ -178,3 +178,9 @@ impl<K, V> Iterator for IntoIter<K, V> {
         }
     }
 }
+
+impl<K, V> ExactSizeIterator for IntoIter<K, V> {
+    fn len(&self) -> usize {
+        self.len
+    }
+}