library/coretests/tests/macros.rs

#![allow(unused_must_use)]

use std::{assert_matches, debug_assert_matches};

#[allow(dead_code)]
trait Trait {
    fn blah(&self);
}

#[allow(dead_code)]
struct Struct;

impl Trait for Struct {
    cfg_select! {
        feature = "blah" => {
            fn blah(&self) {
                unimplemented!();
            }
        }
        _ => {
            fn blah(&self) {
                unimplemented!();
            }
        }
    }
}

#[test]
fn assert_eq_trailing_comma() {
    assert_eq!(1, 1,);
}

#[test]
fn assert_escape() {
    assert!(r#"☃\backslash"#.contains("\\"));
}

#[test]
fn assert_ne_trailing_comma() {
    assert_ne!(1, 2,);
}

#[rustfmt::skip]
#[test]
fn matches_leading_pipe() {
    matches!(1, | 1 | 2 | 3);
}

#[test]
fn cfg_select_basic() {
    cfg_select! {
        target_pointer_width = "64" => {
            fn f0_() -> bool {
                true
            }
        }
        _ => {}
    }

    cfg_select! {
        unix => {
            fn f1_() -> bool {
                true
            }
        }
        _ => {
            fn f1_() -> bool {
                false
            }
        }
    }

    cfg_select! {
        target_pointer_width = "32" => {
            fn f2_() -> bool {
                false
            }
        }
        target_pointer_width = "64" => {
            fn f2_() -> bool {
                true
            }
        }
    }

    cfg_select! {
        target_pointer_width = "16" => {
            fn f3_() -> i32 {
                1
            }
        }
        _ => {
            fn f3_() -> i32 {
                2
            }
        }
    }

    #[cfg(target_pointer_width = "64")]
    assert!(f0_());

    #[cfg(unix)]
    assert!(f1_());
    #[cfg(not(unix))]
    assert!(!f1_());

    #[cfg(target_pointer_width = "32")]
    assert!(!f2_());
    #[cfg(target_pointer_width = "64")]
    assert!(f2_());

    #[cfg(not(target_pointer_width = "16"))]
    assert_eq!(f3_(), 2);
}

#[test]
fn cfg_select_debug_assertions() {
    cfg_select! {
        debug_assertions => {
            assert!(cfg!(debug_assertions));
            assert_eq!(4, 2 + 2);
        }
        _ => {
            assert!(cfg!(not(debug_assertions)));
            assert_eq!(10, 5 + 5);
        }
    }
}

#[cfg(target_pointer_width = "64")]
#[test]
fn cfg_select_no_duplication_on_64() {
    cfg_select! {
        windows => {
            fn foo() {}
        }
        unix => {
            fn foo() {}
        }
        target_pointer_width = "64" => {
            fn foo() {}
        }
    }
    foo();
}

#[test]
fn cfg_select_options() {
    cfg_select! {
        test => {
            use core::option::Option as Option2;
            fn works1() -> Option2<u32> {
                Some(1)
            }
        }
        _ => {
            fn works1() -> Option<u32> {
                None
            }
        }
    }

    cfg_select! {
        feature = "foo" => {
            fn works2() -> bool {
                false
            }
        }
        test => {
            fn works2() -> bool {
                true
            }
        }
        _ => {
            fn works2() -> bool {
                false
            }
        }
    }

    cfg_select! {
        feature = "foo" => {
            fn works3() -> bool {
                false
            }
        }
        _ => {
            fn works3() -> bool {
                true
            }
        }
    }

    cfg_select! {
        test => {
            use core::option::Option as Option3;
            fn works4() -> Option3<u32> {
                Some(1)
            }
        }
    }

    cfg_select! {
        feature = "foo" => {
            fn works5() -> bool {
                false
            }
        }
        test => {
            fn works5() -> bool {
                true
            }
        }
    }

    assert!(works1().is_some());
    assert!(works2());
    assert!(works3());
    assert!(works4().is_some());
    assert!(works5());
}

#[test]
fn cfg_select_two_functions() {
    cfg_select! {
        target_pointer_width = "64" => {
            fn foo1() {}
            fn bar1() {}
        }
        _ => {
            fn foo2() {}
            fn bar2() {}
        }
    }

    #[cfg(target_pointer_width = "64")]
    {
        foo1();
        bar1();
    }
    #[cfg(not(target_pointer_width = "64"))]
    {
        foo2();
        bar2();
    }
}

fn _accepts_expressions() -> i32 {
    cfg_select! {
        unix => 1,
        _ => 2,
    }
}

fn _accepts_only_wildcard() -> i32 {
    cfg_select! {
        _ => 1,
    }
}

// The current implementation expands to a macro call, which allows the use of expression
// statements.
fn _allows_stmt_expr_attributes() {
    let one = 1;
    let two = 2;
    cfg_select! {
        unix => {
            one * two;
        }
        _ => {
            one + two;
        }
    }
}

fn _expression() {
    let _ = cfg_select!(
        windows => " XP",
        _ => "",
    );
}

#[deny(non_exhaustive_omitted_patterns)]
fn _matches_does_not_trigger_non_exhaustive_omitted_patterns_lint(o: core::sync::atomic::Ordering) {
    // Ordering is a #[non_exhaustive] enum from a separate crate
    let _m = matches!(o, core::sync::atomic::Ordering::Relaxed);
}

struct MutRefWithDrop<'a>(&'a mut u32);

// MutRefWithDrop needs to have a non-trivial drop to encounter potential lifetime issues if the
// macros don't introduce a temporary scope.
impl Drop for MutRefWithDrop<'_> {
    fn drop(&mut self) {
        *self.0 = u32::MAX;
    }
}

#[test]
fn temporary_scope_introduction() {
    // Fails to compile if the macros don't introduce a temporary scope, since `&mut val` would
    // create a second mutable borrow while `MutRefWithDrop` still holds a unique ref.
    // See https://github.com/rust-lang/rust/issues/154406 for reference.
    let mut val = 0;

    (assert_matches!(*MutRefWithDrop(&mut val).0, 0), std::mem::take(&mut val));
    (assert_matches!(*MutRefWithDrop(&mut val).0, 0, "msg"), std::mem::take(&mut val));
    (debug_assert_matches!(*MutRefWithDrop(&mut val).0, 0), std::mem::take(&mut val));
    (debug_assert_matches!(*MutRefWithDrop(&mut val).0, 0, "msg"), std::mem::take(&mut val));

    (assert_eq!(*MutRefWithDrop(&mut val).0, 0), std::mem::take(&mut val));
    (assert_eq!(*MutRefWithDrop(&mut val).0, 0, "msg"), std::mem::take(&mut val));
    (debug_assert_eq!(*MutRefWithDrop(&mut val).0, 0), std::mem::take(&mut val));
    (debug_assert_eq!(*MutRefWithDrop(&mut val).0, 0, "msg"), std::mem::take(&mut val));

    (assert_ne!(*MutRefWithDrop(&mut val).0, 1), std::mem::take(&mut val));
    (assert_ne!(*MutRefWithDrop(&mut val).0, 1, "msg"), std::mem::take(&mut val));
    (debug_assert_ne!(*MutRefWithDrop(&mut val).0, 1), std::mem::take(&mut val));
    (debug_assert_ne!(*MutRefWithDrop(&mut val).0, 1, "msg"), std::mem::take(&mut val));

    (assert!(*MutRefWithDrop(&mut val).0 == 0), std::mem::take(&mut val));
    (assert!(*MutRefWithDrop(&mut val).0 == 0, "msg"), std::mem::take(&mut val));
}