src/tools/clippy/tests/ui/mut_from_ref.rs

   1 #![allow(unused, clippy::needless_lifetimes)]
   2 #![warn(clippy::mut_from_ref)]
   3
   4 struct Foo;
   5
   6 impl Foo {
   7     fn this_wont_hurt_a_bit(&self) -> &mut Foo {
   8         unsafe { unimplemented!() }
   9     }
  10 }
  11
  12 trait Ouch {
  13     fn ouch(x: &Foo) -> &mut Foo;
  14 }
  15
  16 impl Ouch for Foo {
  17     fn ouch(x: &Foo) -> &mut Foo {
  18         unsafe { unimplemented!() }
  19     }
  20 }
  21
  22 fn fail(x: &u32) -> &mut u16 {
  23     unsafe { unimplemented!() }
  24 }
  25
  26 fn fail_lifetime<'a>(x: &'a u32, y: &mut u32) -> &'a mut u32 {
  27     unsafe { unimplemented!() }
  28 }
  29
  30 fn fail_double<'a, 'b>(x: &'a u32, y: &'a u32, z: &'b mut u32) -> &'a mut u32 {
  31     unsafe { unimplemented!() }
  32 }
  33
  34 // this is OK, because the result borrows y
  35 fn works<'a>(x: &u32, y: &'a mut u32) -> &'a mut u32 {
  36     unsafe { unimplemented!() }
  37 }
  38
  39 // this is also OK, because the result could borrow y
  40 fn also_works<'a>(x: &'a u32, y: &'a mut u32) -> &'a mut u32 {
  41     unsafe { unimplemented!() }
  42 }
  43
  44 unsafe fn also_broken(x: &u32) -> &mut u32 {
  45     unimplemented!()
  46 }
  47
  48 fn without_unsafe(x: &u32) -> &mut u32 {
  49     unimplemented!()
  50 }
  51
  52 fn main() {
  53     //TODO
  54 }