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// Test the trivial_casts and trivial_numeric_casts lints. For each error we also
// check that the cast can be done using just coercion.
#![deny(trivial_casts, trivial_numeric_casts)]
trait Foo {
fn foo(&self) {}
}
pub struct Bar;
impl Foo for Bar {}
pub fn main() {
// Numeric
let _ = 42_i32 as i32; //~ ERROR trivial numeric cast: `i32` as `i32`
let _: i32 = 42_i32;
let _ = 42_u8 as u8; //~ ERROR trivial numeric cast: `u8` as `u8`
let _: u8 = 42_u8;
// & to * pointers
let x: &u32 = &42;
let _ = x as *const u32; //~ERROR trivial cast: `&u32` as `*const u32`
let _: *const u32 = x;
let x: &mut u32 = &mut 42;
let _ = x as *mut u32; //~ERROR trivial cast: `&mut u32` as `*mut u32`
let _: *mut u32 = x;
// unsize array
let x: &[u32; 3] = &[42, 43, 44];
let _ = x as &[u32]; //~ERROR trivial cast: `&[u32; 3]` as `&[u32]`
let _ = x as *const [u32]; //~ERROR trivial cast: `&[u32; 3]` as `*const [u32]`
let _: &[u32] = x;
let _: *const [u32] = x;
let x: &mut [u32; 3] = &mut [42, 43, 44];
let _ = x as &mut [u32]; //~ERROR trivial cast: `&mut [u32; 3]` as `&mut [u32]`
let _ = x as *mut [u32]; //~ERROR trivial cast: `&mut [u32; 3]` as `*mut [u32]`
let _: &mut [u32] = x;
let _: *mut [u32] = x;
let x: Box<[u32; 3]> = Box::new([42, 43, 44]);
let _ = x as Box<[u32]>;
//~^ ERROR trivial cast: `Box<[u32; 3]>` as `Box<[u32]>`
let x: Box<[u32; 3]> = Box::new([42, 43, 44]);
let _: Box<[u32]> = x;
// unsize trait
let x: &Bar = &Bar;
let _ = x as &dyn Foo; //~ERROR trivial cast: `&Bar` as `&dyn Foo`
let _ = x as *const dyn Foo; //~ERROR trivial cast: `&Bar` as `*const dyn Foo`
let _: &dyn Foo = x;
let _: *const dyn Foo = x;
let x: &mut Bar = &mut Bar;
let _ = x as &mut dyn Foo; //~ERROR trivial cast: `&mut Bar` as `&mut dyn Foo`
let _ = x as *mut dyn Foo; //~ERROR trivial cast: `&mut Bar` as `*mut dyn Foo`
let _: &mut dyn Foo = x;
let _: *mut dyn Foo = x;
let x: Box<Bar> = Box::new(Bar);
let _ = x as Box<dyn Foo>; //~ERROR `Box<Bar>` as `Box<dyn Foo>`
let x: Box<Bar> = Box::new(Bar);
let _: Box<dyn Foo> = x;
// functions
fn baz(_x: i32) {}
let _ = &baz as &dyn Fn(i32); //~ERROR `&fn(i32) {baz}` as `&dyn Fn(i32)`
let _: &dyn Fn(i32) = &baz;
let x = |_x: i32| {};
let _ = &x as &dyn Fn(i32); //~ERROR trivial cast
let _: &dyn Fn(i32) = &x;
}
// subtyping
pub fn test_subtyping<'a, 'b: 'a>(a: &'a Bar, b: &'b Bar) {
let _ = a as &'a Bar; //~ERROR trivial cast
let _: &'a Bar = a;
let _ = b as &'a Bar; //~ERROR trivial cast
let _: &'a Bar = b;
let _ = b as &'b Bar; //~ERROR trivial cast
let _: &'b Bar = b;
}
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