45 lines
1.0 KiB
Rust
45 lines
1.0 KiB
Rust
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use std::mem::transmute;
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fn get_flag<const FlagSet: bool, const ShortName: char>() -> Option<char> {
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if FlagSet {
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Some(ShortName)
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} else {
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None
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}
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}
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union CharRaw {
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byte: u8,
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character: char,
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}
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union BoolRaw {
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byte: u8,
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boolean: bool,
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}
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const char_raw: CharRaw = CharRaw { byte: 0xFF };
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const bool_raw: BoolRaw = BoolRaw { byte: 0x42 };
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fn main() {
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// Test that basic cases don't work
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assert!(get_flag::<true, 'c'>().is_some());
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assert!(get_flag::<false, 'x'>().is_none());
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get_flag::<false, 0xFF>();
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//~^ ERROR mismatched types
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get_flag::<7, 'c'>();
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//~^ ERROR mismatched types
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get_flag::<42, 0x5ad>();
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//~^ ERROR mismatched types
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//~| ERROR mismatched types
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get_flag::<false, { unsafe { char_raw.character } }>();
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//~^ ERROR it is undefined behavior
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get_flag::<{ unsafe { bool_raw.boolean } }, 'z'>();
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//~^ ERROR it is undefined behavior
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get_flag::<{ unsafe { bool_raw.boolean } }, { unsafe { char_raw.character } }>();
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//~^ ERROR it is undefined behavior
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//~| ERROR it is undefined behavior
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}
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