9058bf2100
This is one of the behaviors we no longer allow in NLL. Since it can lead to undefined behavior, I think it's definitely worth making it a hard error without waiting to turn off migration mode (#58781). Closes #60450. My ulterior motive here is making it impossible to leave variables partially initialized across a yield (see discussion at #63035), so tests are included for that.
19 lines
402 B
Rust
19 lines
402 B
Rust
#![feature(never_type)]
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enum Helper<T, U> {
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T(T, [!; 0]),
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#[allow(dead_code)]
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U(U),
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}
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fn transmute<T, U>(t: T) -> U {
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let Helper::U(u) = Helper::T(t, []);
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//~^ ERROR refutable pattern in local binding: `T(_, _)` not covered
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u
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//~^ ERROR use of possibly uninitialized variable: `u`
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}
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fn main() {
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println!("{:?}", transmute::<&str, (*const u8, u64)>("type safety"));
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}
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