Perhaps that comment should be part of the documentation? I'm thinking:

```D
    static immutable base = [1, 2, 3, 2, 4, 2, 5, 2];

    int[] arr = base[].dup;

    // using a string-based predicate
    assert(remove!("a == 2")(arr) == [ 1, 3, 4, 5 ]);

    //The original array contents have been modified,
    //so we need to reset it to its original state.
    //The length is unmodified though.
    arr[] = base[];

    // using a lambda predicate
    assert(remove!(a => a == 2)(arr) == [ 1, 3, 4, 5 ]);
```
As you wish. It looks fine as is too.