1 //! The `bitcast` and `bitflags_bits` macros.
2 
3 #![allow(unused_macros)]
4 
5 // Ensure that the source and destination types are both primitive integer
6 // types and the same size, and then bitcast.
7 macro_rules! bitcast {
8     ($x:expr) => {{
9         if false {
10             // Ensure the source and destinations are primitive integer types.
11             let _ = !$x;
12             let _ = $x as u8;
13             0
14         } else if false {
15             // Ensure that the source and destinations are the same size.
16             // SAFETY: This code is under an `if false`.
17             #[allow(unsafe_code, unused_unsafe, clippy::useless_transmute)]
18             unsafe {
19                 ::core::mem::transmute($x)
20             }
21         } else {
22             // Do the conversion.
23             $x as _
24         }
25     }};
26 }
27 
28 /// Return a [`bitcast`] of the value of `$x.bits()`, where `$x` is a
29 /// `bitflags` type.
30 macro_rules! bitflags_bits {
31     ($x:expr) => {{
32         bitcast!($x.bits())
33     }};
34 }
35