Implement IntoIterator for &Repeated{View,Mut}

googletest matchers use this. Unfortunately, we still can't
use `elements_are!` with them:
google/googletest-rust#351

PiperOrigin-RevId: 599281808

rust/repeated.rs

@@ -418,6 +418,30 @@ where
     }
 }
 
+impl<'msg, T> iter::IntoIterator for &'_ RepeatedView<'msg, T>
+where
+    T: ProxiedInRepeated + ?Sized + 'msg,
+{
+    type Item = View<'msg, T>;
+    type IntoIter = RepeatedIter<'msg, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        RepeatedIter { view: *self, current_index: 0 }
+    }
+}
+
+impl<'borrow, T> iter::IntoIterator for &'borrow RepeatedMut<'_, T>
+where
+    T: ProxiedInRepeated + ?Sized + 'borrow,
+{
+    type Item = View<'borrow, T>;
+    type IntoIter = RepeatedIter<'borrow, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        RepeatedIter { view: self.as_view(), current_index: 0 }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

rust/test/shared/accessors_repeated_test.rs

@@ -15,6 +15,7 @@ macro_rules! generate_repeated_numeric_test {
           #[test]
           fn [< test_repeated_ $field _accessors >]() {
               let mut msg = TestAllTypes::new();
+              assert_that!(msg.[< repeated_ $field >](), empty());
               assert_that!(msg.[< repeated_ $field >]().len(), eq(0));
               assert_that!(msg.[<repeated_ $field >]().get(0), none());
 
@@ -82,6 +83,7 @@ generate_repeated_numeric_test!(
 #[test]
 fn test_repeated_bool_accessors() {
     let mut msg = TestAllTypes::new();
+    assert_that!(msg.repeated_bool(), empty());
     assert_that!(msg.repeated_bool().len(), eq(0));
     assert_that!(msg.repeated_bool().get(0), none());
 
@@ -116,6 +118,7 @@ fn test_repeated_enum_accessors() {
     use TestAllTypes_::NestedEnum;
 
     let mut msg = TestAllTypes::new();
+    assert_that!(msg.repeated_nested_enum(), empty());
     assert_that!(msg.repeated_nested_enum().len(), eq(0));
     assert_that!(msg.repeated_nested_enum().get(0), none());