[move] Fix subtyping bug in typing (#16841)

## Description 

Fixes a small bug in subtyping

## Test Plan 

Added a new test, plus everythong else still works

---
If your changes are not user-facing and do not break anything, you can
skip the following section. Otherwise, please briefly describe what has
changed under the Release Notes section.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

external-crates/move/crates/move-compiler/src/typing/translate.rs

@@ -1019,10 +1019,16 @@ fn subtype_no_report(
     let subst = std::mem::replace(&mut context.subst, Subst::empty());
     let lhs = core::ready_tvars(&subst, pre_lhs);
     let rhs = core::ready_tvars(&subst, pre_rhs);
-    core::subtype(subst, &lhs, &rhs).map(|(next_subst, ty)| {
-        context.subst = next_subst;
-        ty
-    })
+    match core::subtype(subst.clone(), &lhs, &rhs) {
+        Ok((next_subst, ty))  => {
+            context.subst = next_subst;
+            Ok(ty)
+        }
+        Err(err) => {
+            context.subst = subst;
+            Err(err)
+        }
+    }
 }
 
 fn subtype_impl<T: ToString, F: FnOnce() -> T>(

external-crates/move/crates/move-compiler/tests/move_2024/typing/num_infer.exp

@@ -0,0 +1,11 @@
+error[E04007]: incompatible types
+   ┌─ tests/move_2024/typing/num_infer.move:27:34
+   │
+ 5 │     native public fun vborrow<Element>(v: &vector<Element>, i: u64): &Element;
+   │                                                                --- Expected: 'u64'
+   ·
+26 │         let idx = rnd % (matches.length() as u256);
+   │                                              ---- Given: 'u256'
+27 │         let game = orders.remove(matches[idx]);
+   │                                  ^^^^^^^^^^^^ Invalid call of 'std::vector::vborrow'. Invalid argument for parameter 'i'
+

external-crates/move/crates/move-compiler/tests/move_2024/typing/num_infer.move

@@ -0,0 +1,30 @@
+
+#[defines_primitive(vector)]
+module std::vector {
+    #[syntax(index)]
+    native public fun vborrow<Element>(v: &vector<Element>, i: u64): &Element;
+    #[syntax(index)]
+    native public fun vborrow_mut<Element>(v: &mut vector<Element>, i: u64): &mut Element;
+    native public fun remove<Element>(v: &mut vector<Element>, i: u64): Element;
+    native public fun length<Element>(v: &vector<Element>): u64;
+}
+
+module a::pool {
+    public struct Order has store, drop { value: u8 }
+
+    public fun find_match(
+        orders: &mut vector<Order>,
+    ): Option<Order> {
+        let (mut i, len) = (0, orders.length());
+        let mut matches = vector<u64>[];
+
+        while (i < len) {
+            i = i + 1;
+        };
+
+        let rnd = 100u256;
+        let idx = rnd % (matches.length() as u256);
+        let game = orders.remove(matches[idx]);
+        option::some(game)
+    }
+}