Cherry pick #18842 (#18845)

## Description 

- Cherry pick #18842
- Source only change, does not affect devnet/testnet or any other build 

## Test plan 

- CI

---

## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:
- [ ] REST API:

crates/sui-framework/packages/move-stdlib/sources/vector.move

@@ -238,7 +238,7 @@ module std::vector {
 
     /// Finds the index of first element in the vector `v` that satisfies the predicate `f`.
     /// Returns `some(index)` if such an element is found, otherwise `none()`.
-    public macro fun find_index<$T>($v: vector<$T>, $f: |&$T| -> bool): Option<u64> {
+    public macro fun find_index<$T>($v: &vector<$T>, $f: |&$T| -> bool): Option<u64> {
         let v = $v;
         'find_index: {
             v.length().do!(|i| if ($f(&v[i])) return 'find_index option::some(i));

crates/sui-framework/packages/move-stdlib/tests/vector_tests.move

@@ -677,6 +677,11 @@ module std::vector_tests {
         let r = vector[0, 10, 100, 1_000];
         assert!(r.find_index!(|e| *e == 100).destroy_some() == 2);
         assert!(r.find_index!(|e| *e == 10_000).is_none());
+
+        let v = vector[Droppable{}, Droppable{}];
+        let idx = v.find_index!(|e| e == Droppable{});
+        assert!(idx.destroy_some() == 0);
+        assert!(&v[idx.destroy_some()] == Droppable{});
     }
 
     #[test]

external-crates/move/crates/move-analyzer/tests/dot_completion.exp

@@ -107,7 +107,7 @@ Method 'filter!()'
 Method 'find_index!()'
     INSERT TEXT: 'find_index!(|${1}| ${2})'
     TARGET     : '(std::vector::find_index)'
-    TYPE       : 'fun <$T>(vector<$T>, |&$T| -> bool): Option'
+    TYPE       : 'fun <$T>(&vector<$T>, |&$T| -> bool): Option'
 Method 'fold!()'
     INSERT TEXT: 'fold!(${1:init}, |${2}, ${3}| ${4})'
     TARGET     : '(std::vector::fold)'

external-crates/move/crates/move-stdlib/sources/vector.move

@@ -238,7 +238,7 @@ module std::vector {
 
     /// Finds the index of first element in the vector `v` that satisfies the predicate `f`.
     /// Returns `some(index)` if such an element is found, otherwise `none()`.
-    public macro fun find_index<$T>($v: vector<$T>, $f: |&$T| -> bool): Option<u64> {
+    public macro fun find_index<$T>($v: &vector<$T>, $f: |&$T| -> bool): Option<u64> {
         let v = $v;
         'find_index: {
             v.length().do!(|i| if ($f(&v[i])) return 'find_index option::some(i));

external-crates/move/crates/move-stdlib/tests/vector_tests.move

@@ -677,6 +677,11 @@ module std::vector_tests {
         let r = vector[0, 10, 100, 1_000];
         assert!(r.find_index!(|e| *e == 100).destroy_some() == 2);
         assert!(r.find_index!(|e| *e == 10_000).is_none());
+
+        let v = vector[Droppable{}, Droppable{}];
+        let idx = v.find_index!(|e| e == Droppable{});
+        assert!(idx.destroy_some() == 0);
+        assert!(&v[idx.destroy_some()] == Droppable{});
     }
 
     #[test]