From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- src/test/ui/consts/const-eval/union-ub.rs | 43 +++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 src/test/ui/consts/const-eval/union-ub.rs (limited to 'src/test/ui/consts/const-eval/union-ub.rs') diff --git a/src/test/ui/consts/const-eval/union-ub.rs b/src/test/ui/consts/const-eval/union-ub.rs new file mode 100644 index 000000000..c1bfe69a7 --- /dev/null +++ b/src/test/ui/consts/const-eval/union-ub.rs @@ -0,0 +1,43 @@ +// stderr-per-bitwidth +#![allow(const_err)] // make sure we cannot allow away the errors tested here + +#[repr(C)] +union DummyUnion { + unit: (), + u8: u8, + bool: bool, +} + +#[repr(C)] +#[derive(Copy, Clone)] +enum Enum { + A, + B, + C, +} + +#[derive(Copy, Clone)] +#[repr(C)] +union Foo { + a: bool, + b: Enum, +} + +#[repr(C)] +union Bar { + foo: Foo, + u8: u8, +} + +// the value is not valid for bools +const BAD_BOOL: bool = unsafe { DummyUnion { u8: 42 }.bool}; +//~^ ERROR it is undefined behavior to use this value +const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool}; +//~^ ERROR it is undefined behavior to use this value + +// The value is not valid for any union variant, but that's fine +// unions are just a convenient way to transmute bits around +const BAD_UNION: Foo = unsafe { Bar { u8: 42 }.foo }; + + +fn main() {} -- cgit v1.2.3