rust/tests/ui/packed-struct/packed-struct-generic-transmute.rs

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// This assumes the packed and non-packed structs are different sizes.
// the error points to the start of the file, not the line with the
// transmute
2018-12-21 14:15:47 +00:00
// error-pattern: cannot transmute between types of different sizes, or dependently-sized types
core: Remove the cast module This commit revisits the `cast` module in libcore and libstd, and scrutinizes all functions inside of it. The result was to remove the `cast` module entirely, folding all functionality into the `mem` module. Specifically, this is the fate of each function in the `cast` module. * transmute - This function was moved to `mem`, but it is now marked as #[unstable]. This is due to planned changes to the `transmute` function and how it can be invoked (see the #[unstable] comment). For more information, see RFC 5 and #12898 * transmute_copy - This function was moved to `mem`, with clarification that is is not an error to invoke it with T/U that are different sizes, but rather that it is strongly discouraged. This function is now #[stable] * forget - This function was moved to `mem` and marked #[stable] * bump_box_refcount - This function was removed due to the deprecation of managed boxes as well as its questionable utility. * transmute_mut - This function was previously deprecated, and removed as part of this commit. * transmute_mut_unsafe - This function doesn't serve much of a purpose when it can be achieved with an `as` in safe code, so it was removed. * transmute_lifetime - This function was removed because it is likely a strong indication that code is incorrect in the first place. * transmute_mut_lifetime - This function was removed for the same reasons as `transmute_lifetime` * copy_lifetime - This function was moved to `mem`, but it is marked `#[unstable]` now due to the likelihood of being removed in the future if it is found to not be very useful. * copy_mut_lifetime - This function was also moved to `mem`, but had the same treatment as `copy_lifetime`. * copy_lifetime_vec - This function was removed because it is not used today, and its existence is not necessary with DST (copy_lifetime will suffice). In summary, the cast module was stripped down to these functions, and then the functions were moved to the `mem` module. transmute - #[unstable] transmute_copy - #[stable] forget - #[stable] copy_lifetime - #[unstable] copy_mut_lifetime - #[unstable] [breaking-change]
2014-05-09 17:34:51 +00:00
use std::mem;
#[repr(packed)]
struct Foo<T,S> {
bar: T,
baz: S
}
struct Oof<T, S> {
rab: T,
zab: S
}
fn main() {
let foo = Foo { bar: [1u8, 2, 3, 4, 5], baz: 10i32 };
unsafe {
let oof: Oof<[u8; 5], i32> = mem::transmute(foo);
println!("{:?} {:?}", &oof.rab[..], oof.zab);
}
}