Rollup merge of #97011 - JohnTitor:issue-28935, r=compiler-errors

Add regression test for #28935

Closes #28935, one of the ancient issues can be closed :)
r? `@compiler-errors`

Author: matthiaskrgr

src/test/ui/inference/issue-28935.rs

@@ -0,0 +1,9 @@
+// check-pass
+
+use std::cell::RefCell;
+
+pub fn f(v: Vec<RefCell<u8>>) {
+    let _t = &mut *v[0].borrow_mut();
+}
+
+fn main() {}