1 error[E0502]: cannot borrow `*collection` as mutable because it is also borrowed as immutable
2 --> $DIR/issue-42106.rs:3:5
4 LL | let _a = &collection;
5 | ----------- immutable borrow occurs here
6 LL | collection.swap(1, 2);
7 | ^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
9 | ------------ immutable borrow later used here
11 error: aborting due to previous error
13 For more information about this error, try `rustc --explain E0502`.