mirror of https://github.com/rust-lang/rust
96 lines
2.0 KiB
Rust
96 lines
2.0 KiB
Rust
//@ build-fail
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//@ compile-flags: -Copt-level=0 -Zpolymorphize=on
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#![feature(rustc_attrs)]
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// This test checks that `T` is considered used in `foo`, because it is used in a predicate for
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// `I`, which is used.
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#[rustc_polymorphize_error]
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fn bar<I>() {
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//~^ ERROR item has unused generic parameters
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}
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#[rustc_polymorphize_error]
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fn foo<I, T>(_: I)
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//~^ ERROR item has unused generic parameters
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where
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I: Iterator<Item = T>,
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{
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bar::<I>()
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}
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#[rustc_polymorphize_error]
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fn baz<I, T>(_: I)
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//~^ ERROR item has unused generic parameters
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where
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std::iter::Repeat<I>: Iterator<Item = T>,
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{
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bar::<I>()
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}
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// In addition, check that `I` is considered used in `next::{{closure}}`, because `T` is used and
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// `T` is really just `I::Item`. `E` is used due to the fixed-point marking of predicates.
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pub(crate) struct Foo<'a, I, E>(I, &'a E);
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impl<'a, I, T: 'a, E> Iterator for Foo<'a, I, E>
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where
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I: Iterator<Item = &'a (T, E)>,
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{
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type Item = T;
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#[rustc_polymorphize_error]
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fn next(&mut self) -> Option<Self::Item> {
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self.find(|_| true)
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//~^ ERROR item has unused generic parameters
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}
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}
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// Furthermore, check that `B` is considered used because `C` is used, and that `A` is considered
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// used because `B` is now used.
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trait Baz<Z> {}
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impl Baz<u16> for u8 {}
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impl Baz<u32> for u16 {}
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#[rustc_polymorphize_error]
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fn quux<A, B, C: Default>() -> usize
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//~^ ERROR item has unused generic parameters
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where
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A: Baz<B>,
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B: Baz<C>,
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{
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std::mem::size_of::<C>()
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}
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// Finally, check that `F` is considered used because `G` is used when neither are in the self-ty
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// of the predicate.
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trait Foobar<F, G> {}
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impl Foobar<u32, u32> for () {}
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#[rustc_polymorphize_error]
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fn foobar<F, G>() -> usize
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//~^ ERROR item has unused generic parameters
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where
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(): Foobar<F, G>,
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{
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std::mem::size_of::<G>()
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}
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fn main() {
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let x = &[2u32];
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foo(x.iter());
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baz(x.iter());
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let mut a = Foo([(1u32, 1u16)].iter(), &1u16);
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let _ = a.next();
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let _ = quux::<u8, u16, u32>();
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let _ = foobar::<u32, u32>();
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}
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