1 // Test the trivial_casts and trivial_numeric_casts lints. For each error we also
2 // check that the cast can be done using just coercion.
4 #![deny(trivial_casts, trivial_numeric_casts)]
16 let _ = 42_i32 as i32; //~ ERROR trivial numeric cast: `i32` as `i32`
19 let _ = 42_u8 as u8; //~ ERROR trivial numeric cast: `u8` as `u8`
24 let _ = x as *const u32; //~ERROR trivial cast: `&u32` as `*const u32`
25 let _: *const u32 = x;
27 let x: &mut u32 = &mut 42;
28 let _ = x as *mut u32; //~ERROR trivial cast: `&mut u32` as `*mut u32`
32 let x: &[u32; 3] = &[42, 43, 44];
33 let _ = x as &[u32]; //~ERROR trivial cast: `&[u32; 3]` as `&[u32]`
34 let _ = x as *const [u32]; //~ERROR trivial cast: `&[u32; 3]` as `*const [u32]`
36 let _: *const [u32] = x;
38 let x: &mut [u32; 3] = &mut [42, 43, 44];
39 let _ = x as &mut [u32]; //~ERROR trivial cast: `&mut [u32; 3]` as `&mut [u32]`
40 let _ = x as *mut [u32]; //~ERROR trivial cast: `&mut [u32; 3]` as `*mut [u32]`
41 let _: &mut [u32] = x;
42 let _: *mut [u32] = x;
44 let x: Box<[u32; 3]> = Box::new([42, 43, 44]);
45 let _ = x as Box<[u32]>;
46 //~^ ERROR trivial cast: `Box<[u32; 3]>` as `Box<[u32]>`
47 let x: Box<[u32; 3]> = Box::new([42, 43, 44]);
48 let _: Box<[u32]> = x;
52 let _ = x as &dyn Foo; //~ERROR trivial cast: `&Bar` as `&dyn Foo`
53 let _ = x as *const dyn Foo; //~ERROR trivial cast: `&Bar` as `*const dyn Foo`
55 let _: *const dyn Foo = x;
57 let x: &mut Bar = &mut Bar;
58 let _ = x as &mut dyn Foo; //~ERROR trivial cast: `&mut Bar` as `&mut dyn Foo`
59 let _ = x as *mut dyn Foo; //~ERROR trivial cast: `&mut Bar` as `*mut dyn Foo`
60 let _: &mut dyn Foo = x;
61 let _: *mut dyn Foo = x;
63 let x: Box<Bar> = Box::new(Bar);
64 let _ = x as Box<dyn Foo>; //~ERROR `Box<Bar>` as `Box<dyn Foo>`
65 let x: Box<Bar> = Box::new(Bar);
66 let _: Box<dyn Foo> = x;
70 let _ = &baz as &dyn Fn(i32); //~ERROR `&fn(i32) {baz}` as `&dyn Fn(i32)`
71 let _: &dyn Fn(i32) = &baz;
73 let _ = &x as &dyn Fn(i32); //~ERROR trivial cast
74 let _: &dyn Fn(i32) = &x;
78 pub fn test_subtyping<'a, 'b: 'a>(a: &'a Bar, b: &'b Bar) {
79 let _ = a as &'a Bar; //~ERROR trivial cast
81 let _ = b as &'a Bar; //~ERROR trivial cast
83 let _ = b as &'b Bar; //~ERROR trivial cast