src/tools/clippy/src/docs/uninit_assumed_init.txt

   1 ### What it does
   2 Checks for `MaybeUninit::uninit().assume_init()`.
   3
   4 ### Why is this bad?
   5 For most types, this is undefined behavior.
   6
   7 ### Known problems
   8 For now, we accept empty tuples and tuples / arrays
   9 of `MaybeUninit`. There may be other types that allow uninitialized
  10 data, but those are not yet rigorously defined.
  11
  12 ### Example
  13 ```
  14 // Beware the UB
  15 use std::mem::MaybeUninit;
  16
  17 let _: usize = unsafe { MaybeUninit::uninit().assume_init() };
  18 ```
  19
  20 Note that the following is OK:
  21
  22 ```
  23 use std::mem::MaybeUninit;
  24
  25 let _: [MaybeUninit<bool>; 5] = unsafe {
  26     MaybeUninit::uninit().assume_init()
  27 };
  28 ```