95 lines
3.1 KiB
Rust
95 lines
3.1 KiB
Rust
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Test the trivial_cast and trivial_numeric_cast lints. For each error we also
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// check that the cast can be done using just coercion.
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#![deny(trivial_cast, trivial_numeric_cast)]
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trait Foo {
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fn foo(&self) {}
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}
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pub struct Bar;
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impl Foo for Bar {}
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pub fn main() {
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// Numeric
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let _ = 42_i32 as i32; //~ ERROR trivial numeric cast: `i32` as `i32`
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let _: i32 = 42_i32;
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let _ = 42_u8 as u8; //~ ERROR trivial numeric cast: `u8` as `u8`
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let _: u8 = 42_u8;
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// & to * pointers
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let x: &u32 = &42;
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let _ = x as *const u32; //~ERROR trivial cast: `&u32` as `*const u32`
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let _: *const u32 = x;
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let x: &mut u32 = &mut 42;
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let _ = x as *mut u32; //~ERROR trivial cast: `&mut u32` as `*mut u32`
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let _: *mut u32 = x;
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// unsize array
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let x: &[u32; 3] = &[42, 43, 44];
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let _ = x as &[u32]; //~ERROR trivial cast: `&[u32; 3]` as `&[u32]`
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let _ = x as *const [u32]; //~ERROR trivial cast: `&[u32; 3]` as `*const [u32]`
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let _: &[u32] = x;
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let _: *const [u32] = x;
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let x: &mut [u32; 3] = &mut [42, 43, 44];
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let _ = x as &mut [u32]; //~ERROR trivial cast: `&mut [u32; 3]` as `&mut [u32]`
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let _ = x as *mut [u32]; //~ERROR trivial cast: `&mut [u32; 3]` as `*mut [u32]`
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let _: &mut [u32] = x;
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let _: *mut [u32] = x;
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let x: Box<[u32; 3]> = Box::new([42, 43, 44]);
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let _ = x as Box<[u32]>; //~ERROR trivial cast: `Box<[u32; 3]>` as `Box<[u32]>`
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let x: Box<[u32; 3]> = Box::new([42, 43, 44]);
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let _: Box<[u32]> = x;
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// unsize trait
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let x: &Bar = &Bar;
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let _ = x as &Foo; //~ERROR trivial cast: `&Bar` as `&Foo`
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let _ = x as *const Foo; //~ERROR trivial cast: `&Bar` as `*const Foo`
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let _: &Foo = x;
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let _: *const Foo = x;
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let x: &mut Bar = &mut Bar;
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let _ = x as &mut Foo; //~ERROR trivial cast: `&mut Bar` as `&mut Foo`
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let _ = x as *mut Foo; //~ERROR trivial cast: `&mut Bar` as `*mut Foo`
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let _: &mut Foo = x;
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let _: *mut Foo = x;
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let x: Box<Bar> = Box::new(Bar);
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let _ = x as Box<Foo>; //~ERROR trivial cast: `Box<Bar>` as `Box<Foo>`
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let x: Box<Bar> = Box::new(Bar);
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let _: Box<Foo> = x;
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// functions
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fn baz(_x: i32) {}
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let _ = &baz as &Fn(i32); //~ERROR trivial cast: `&fn(i32) {main::baz}` as `&core::ops::Fn(i32)`
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let _: &Fn(i32) = &baz;
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let x = |_x: i32| {};
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let _ = &x as &Fn(i32); //~ERROR trivial cast
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let _: &Fn(i32) = &x;
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}
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// subtyping
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pub fn test_subtyping<'a, 'b: 'a>(a: &'a Bar, b: &'b Bar) {
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let _ = a as &'a Bar; //~ERROR trivial cast
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let _: &'a Bar = a;
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let _ = b as &'a Bar; //~ERROR trivial cast
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let _: &'a Bar = b;
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let _ = b as &'b Bar; //~ERROR trivial cast
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let _: &'b Bar = b;
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}
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