| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| #![feature(nonzero, core)] |
| |
| extern crate core; |
| |
| use core::nonzero::NonZero; |
| use std::mem::size_of; |
| use std::rc::Rc; |
| use std::sync::Arc; |
| |
| trait Trait { fn dummy(&self) { } } |
| trait Mirror { type Image; } |
| impl<T> Mirror for T { type Image = T; } |
| struct ParamTypeStruct<T>(T); |
| struct AssocTypeStruct<T>(<T as Mirror>::Image); |
| |
| fn main() { |
| // Functions |
| assert_eq!(size_of::<fn(isize)>(), size_of::<Option<fn(isize)>>()); |
| assert_eq!(size_of::<extern "C" fn(isize)>(), size_of::<Option<extern "C" fn(isize)>>()); |
| |
| // Slices - &str / &[T] / &mut [T] |
| assert_eq!(size_of::<&str>(), size_of::<Option<&str>>()); |
| assert_eq!(size_of::<&[isize]>(), size_of::<Option<&[isize]>>()); |
| assert_eq!(size_of::<&mut [isize]>(), size_of::<Option<&mut [isize]>>()); |
| |
| // Traits - Box<Trait> / &Trait / &mut Trait |
| assert_eq!(size_of::<Box<Trait>>(), size_of::<Option<Box<Trait>>>()); |
| assert_eq!(size_of::<&Trait>(), size_of::<Option<&Trait>>()); |
| assert_eq!(size_of::<&mut Trait>(), size_of::<Option<&mut Trait>>()); |
| |
| // Pointers - Box<T> |
| assert_eq!(size_of::<Box<isize>>(), size_of::<Option<Box<isize>>>()); |
| |
| // The optimization can't apply to raw pointers |
| assert!(size_of::<Option<*const isize>>() != size_of::<*const isize>()); |
| assert!(Some(0 as *const isize).is_some()); // Can't collapse None to null |
| |
| struct Foo { |
| _a: Box<isize> |
| } |
| struct Bar(Box<isize>); |
| |
| // Should apply through structs |
| assert_eq!(size_of::<Foo>(), size_of::<Option<Foo>>()); |
| assert_eq!(size_of::<Bar>(), size_of::<Option<Bar>>()); |
| // and tuples |
| assert_eq!(size_of::<(u8, Box<isize>)>(), size_of::<Option<(u8, Box<isize>)>>()); |
| // and fixed-size arrays |
| assert_eq!(size_of::<[Box<isize>; 1]>(), size_of::<Option<[Box<isize>; 1]>>()); |
| |
| // Should apply to NonZero |
| assert_eq!(size_of::<NonZero<usize>>(), size_of::<Option<NonZero<usize>>>()); |
| assert_eq!(size_of::<NonZero<*mut i8>>(), size_of::<Option<NonZero<*mut i8>>>()); |
| |
| // Should apply to types that use NonZero internally |
| assert_eq!(size_of::<Vec<isize>>(), size_of::<Option<Vec<isize>>>()); |
| assert_eq!(size_of::<Arc<isize>>(), size_of::<Option<Arc<isize>>>()); |
| assert_eq!(size_of::<Rc<isize>>(), size_of::<Option<Rc<isize>>>()); |
| |
| // Should apply to types that have NonZero transitively |
| assert_eq!(size_of::<String>(), size_of::<Option<String>>()); |
| |
| // Should apply to types where the pointer is substituted |
| assert_eq!(size_of::<&u8>(), size_of::<Option<ParamTypeStruct<&u8>>>()); |
| assert_eq!(size_of::<&u8>(), size_of::<Option<AssocTypeStruct<&u8>>>()); |
| } |