35 lines
614 B
Rust
35 lines
614 B
Rust
// build-fail
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trait C {
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const BOO: usize;
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}
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trait Foo<T> {
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const BAR: usize;
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}
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struct A<T>(T);
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impl<T: C> Foo<T> for A<T> {
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const BAR: usize = [5, 6, 7][T::BOO]; //~ ERROR evaluation of `<A<()> as Foo<()>>::BAR` failed
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}
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fn foo<T: C>() -> &'static usize {
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&<A<T> as Foo<T>>::BAR //~ constant
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}
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impl C for () {
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const BOO: usize = 42;
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}
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impl C for u32 {
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const BOO: usize = 1;
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}
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fn main() {
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println!("{:x}", foo::<()>() as *const usize as usize);
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println!("{:x}", foo::<u32>() as *const usize as usize);
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println!("{:x}", foo::<()>());
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println!("{:x}", foo::<u32>());
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}
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