It is not allowed to manually call destructors in Rust.
Erroneous code example:
```compile_fail,E0040
struct Foo {
x: i32,
}
impl Drop for Foo {
fn drop(&mut self) {
println!("kaboom");
}
}
fn main() {
let mut x = Foo { x: -7 };
x.drop(); // error: explicit use of destructor method
}
```
It is unnecessary to do this since `drop` is called automatically whenever a
value goes out of scope. However, if you really need to drop a value by hand,
you can use the `std::mem::drop` function:
```
struct Foo {
x: i32,
}
impl Drop for Foo {
fn drop(&mut self) {
println!("kaboom");
}
}
fn main() {
let mut x = Foo { x: -7 };
drop(x); // ok!
}
```