src/test/ui/const-eval/issue-44578.rs

   1 // Copyright 2017 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 // must-compile-successfully
  12
  13 trait Foo {
  14     const AMT: usize;
  15 }
  16
  17 enum Bar<A, B> {
  18     First(A),
  19     Second(B),
  20 }
  21
  22 impl<A: Foo, B: Foo> Foo for Bar<A, B> {
  23     const AMT: usize = [A::AMT][(A::AMT > B::AMT) as usize];
  24 }
  25
  26 impl Foo for u8 {
  27     const AMT: usize = 1;
  28 }
  29
  30 impl Foo for u16 {
  31     const AMT: usize = 2;
  32 }
  33
  34 fn main() {
  35     println!("{}", <Bar<u16, u8> as Foo>::AMT); //~ WARN const_err
  36     //~^ WARN const_err
  37 }