// revisions: mirunsafeck thirunsafeck // [thirunsafeck]compile-flags: -Z thir-unsafeck use std::ops::AddAssign; use std::mem::ManuallyDrop; struct NonCopy; impl AddAssign for NonCopy { fn add_assign(&mut self, _: Self) {} } union Foo { a: u8, // non-dropping b: ManuallyDrop, } fn main() { let mut foo = Foo { a: 42 }; foo.a += 5; //~ ERROR access to union field is unsafe *foo.b += NonCopy; //~ ERROR access to union field is unsafe *foo.b = NonCopy; //~ ERROR access to union field is unsafe foo.b = ManuallyDrop::new(NonCopy); foo.a; //~ ERROR access to union field is unsafe let foo = Foo { a: 42 }; foo.b; //~ ERROR access to union field is unsafe let mut foo = Foo { a: 42 }; foo.b = foo.b; //~^ ERROR access to union field is unsafe }