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Rollup merge of rust-lang#90578 - lcnr:add-test, r=Mark-Simulacrum
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add const generics test

cc rust-lang#89829 (comment)

r? rust-lang/project-const-generics
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matthiaskrgr authored Nov 18, 2021
2 parents 281b65a + 8ace192 commit 439afef
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26 changes: 26 additions & 0 deletions src/test/ui/const-generics/invariant.nll.stderr
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@@ -0,0 +1,26 @@
warning: conflicting implementations of trait `SadBee` for type `for<'a> fn(&'a ())`
--> $DIR/invariant.rs:14:1
|
LL | impl SadBee for for<'a> fn(&'a ()) {
| ---------------------------------- first implementation here
...
LL | impl SadBee for fn(&'static ()) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a> fn(&'a ())`
|
= note: `#[warn(coherence_leak_check)]` on by default
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
= note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details

error[E0308]: mismatched types
--> $DIR/invariant.rs:27:5
|
LL | v
| ^ one type is more general than the other
|
= note: expected reference `&Foo<fn(&())>`
found reference `&Foo<for<'a> fn(&'a ())>`

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0308`.
33 changes: 33 additions & 0 deletions src/test/ui/const-generics/invariant.rs
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#![feature(generic_const_exprs)]
#![allow(incomplete_features)]
use std::marker::PhantomData;

trait SadBee {
const ASSOC: usize;
}
// fn(&'static ())` is a supertype of `for<'a> fn(&'a ())` while
// we allow two different impls for these types, leading
// to different const eval results.
impl SadBee for for<'a> fn(&'a ()) {
const ASSOC: usize = 0;
}
impl SadBee for fn(&'static ()) {
//~^ WARNING conflicting implementations of trait
//~| WARNING this was previously accepted
const ASSOC: usize = 100;
}

struct Foo<T: SadBee>([u8; <T as SadBee>::ASSOC], PhantomData<T>)
where
[(); <T as SadBee>::ASSOC]: ;

fn covariant(
v: &'static Foo<for<'a> fn(&'a ())>
) -> &'static Foo<fn(&'static ())> {
v //~ ERROR mismatched types
}

fn main() {
let y = covariant(&Foo([], PhantomData));
println!("{:?}", y.0);
}
26 changes: 26 additions & 0 deletions src/test/ui/const-generics/invariant.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
warning: conflicting implementations of trait `SadBee` for type `for<'a> fn(&'a ())`
--> $DIR/invariant.rs:14:1
|
LL | impl SadBee for for<'a> fn(&'a ()) {
| ---------------------------------- first implementation here
...
LL | impl SadBee for fn(&'static ()) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a> fn(&'a ())`
|
= note: `#[warn(coherence_leak_check)]` on by default
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
= note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details

error[E0308]: mismatched types
--> $DIR/invariant.rs:27:5
|
LL | v
| ^ one type is more general than the other
|
= note: expected reference `&'static Foo<fn(&'static ())>`
found reference `&'static Foo<for<'a> fn(&'a ())>`

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0308`.

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