src/test/run-pass/const-fn.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // A very basic test of const fn functionality.
  12
  13 #![feature(const_fn, const_indexing)]
  14
  15 const fn add(x: u32, y: u32) -> u32 {
  16     x + y
  17 }
  18
  19 const fn sub(x: u32, y: u32) -> u32 {
  20     x - y
  21 }
  22
  23 const unsafe fn div(x: u32, y: u32) -> u32 {
  24     x / y
  25 }
  26
  27 const fn generic<T>(t: T) -> T {
  28     t
  29 }
  30
  31 const fn generic_arr<T: Copy>(t: [T; 1]) -> T {
  32     t[0]
  33 }
  34
  35 const SUM: u32 = add(44, 22);
  36 const DIFF: u32 = sub(44, 22);
  37 const DIV: u32 = unsafe{div(44, 22)};
  38
  39 fn main() {
  40     assert_eq!(SUM, 66);
  41     assert!(SUM != 88);
  42
  43     assert_eq!(DIFF, 22);
  44     assert_eq!(DIV, 2);
  45
  46     let _: [&'static str; sub(100, 99) as usize] = ["hi"];
  47     let _: [&'static str; generic(1)] = ["hi"];
  48     let _: [&'static str; generic_arr([1])] = ["hi"];
  49 }