| // Copyright 2018 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(rustc_attrs, const_fn)] |
| |
| #[rustc_args_required_const(0)] |
| fn foo(_a: i32) { |
| } |
| |
| #[rustc_args_required_const(1)] |
| fn bar(_a: i32, _b: i32) { |
| } |
| |
| const A: i32 = 3; |
| |
| const fn baz() -> i32 { |
| 3 |
| } |
| |
| fn main() { |
| foo(2); |
| foo(2 + 3); |
| const BAZ: i32 = baz(); |
| foo(BAZ); |
| let a = 4; |
| foo(A); |
| foo(a); //~ ERROR: argument 1 is required to be a constant |
| bar(a, 3); |
| bar(a, a); //~ ERROR: argument 2 is required to be a constant |
| } |