rust/tests/ui/lint/dead-code/lint-dead-code-4.rs

#![allow(unused_variables)]
#![allow(non_camel_case_types)]
#![deny(dead_code)]

struct Foo {
    x: usize,
    b: bool, //~ ERROR: field `b` is never read
}

fn field_read(f: Foo) -> usize {
    f.x.pow(2)
}

enum XYZ {
    X, //~ ERROR variants `X` and `Y` are never constructed
    Y {
        a: String,
        b: i32,
        c: i32,
    },
    Z
}

enum ABC { //~ ERROR enum `ABC` is never used
    A,
    B {
        a: String,
        b: i32,
        c: i32,
    },
    C
}

// ensure struct variants get warning for their fields
enum IJK {
    I, //~ ERROR variants `I` and `K` are never constructed
    J {
        a: String,
        b: i32, //~ ERROR fields `b` and `c` are never read
        c: i32,
    },
    K

}

fn struct_variant_partial_use(b: IJK) -> String {
    match b {
        IJK::J { a, b: _, .. } => a,
        _ => "".to_string()
    }
}

fn field_match_in_patterns(b: XYZ) -> String {
    match b {
        XYZ::Y { a, b: _, .. } => a,
        _ => "".to_string()
    }
}

struct Bar {
    x: usize, //~ ERROR: fields `x` and `c` are never read
    b: bool,
    c: bool,
    _guard: ()
}

#[repr(C)]
struct Baz {
    x: u32,
}

fn field_match_in_let(f: Bar) -> bool {
    let Bar { b, c: _, .. } = f;
    b
}

fn main() {
    field_read(Foo { x: 1, b: false });
    field_match_in_patterns(XYZ::Z);
    struct_variant_partial_use(IJK::J { a: "".into(), b: 1, c: -1 });
    field_match_in_let(Bar { x: 42, b: true, c: false, _guard: () });
    let _ = Baz { x: 0 };
}