mirror of https://github.com/rust-lang/rust
44 lines
776 B
Rust
44 lines
776 B
Rust
//@ stderr-per-bitwidth
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#[repr(C)]
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union DummyUnion {
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unit: (),
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u8: u8,
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bool: bool,
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}
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#[repr(C)]
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#[derive(Copy, Clone)]
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enum Enum {
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A,
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B,
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C,
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}
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#[derive(Copy, Clone)]
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#[repr(C)]
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union Foo {
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a: bool,
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b: Enum,
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}
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#[repr(C)]
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union Bar {
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foo: Foo,
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u8: u8,
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}
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// the value is not valid for bools
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const BAD_BOOL: bool = unsafe { DummyUnion { u8: 42 }.bool};
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//~^ ERROR it is undefined behavior to use this value
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const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool};
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//~^ ERROR evaluation of constant value failed
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//~| uninitialized
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// The value is not valid for any union variant, but that's fine
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// unions are just a convenient way to transmute bits around
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const BAD_UNION: Foo = unsafe { Bar { u8: 42 }.foo };
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fn main() {}
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