52 lines
841 B
Rust
52 lines
841 B
Rust
#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
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// Regression test for a specialization-related ICE (#39448).
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trait A: Sized {
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fn foo(self, _: Self) -> Self {
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self
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}
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}
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impl A for u8 {}
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impl A for u16 {}
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impl FromA<u8> for u16 {
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fn from(x: u8) -> u16 {
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x as u16
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}
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}
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trait FromA<T> {
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fn from(t: T) -> Self;
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}
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impl<T: A, U: A + FromA<T>> FromA<T> for U {
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//~^ ERROR cycle detected when computing whether impls specialize one another
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default fn from(x: T) -> Self {
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ToA::to(x)
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}
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}
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trait ToA<T> {
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fn to(self) -> T;
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}
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impl<T, U> ToA<U> for T
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where
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U: FromA<T>,
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{
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fn to(self) -> U {
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U::from(self)
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}
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}
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#[allow(dead_code)]
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fn foo<T: A, U: A>(x: T, y: U) -> U {
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x.foo(y.to()).to()
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}
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fn main() {
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let z = foo(8u8, 1u16);
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}
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