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Adapt trait object coercion tests to the status quo

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This commit is contained in:
Florian Diebold 2020-07-11 18:42:30 +02:00
parent 94f5f69ff4
commit 00bda1cafb
1 changed files with 51 additions and 4 deletions
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55
crates/ra_hir_ty/src/tests/coercion.rs
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@ -662,7 +662,53 @@ fn test() {
}
#[test]
fn coerce_unsize_trait_object() {
fn coerce_unsize_trait_object_simple() {
assert_snapshot!(
infer_with_mismatches(r#"
#[lang = "sized"]
pub trait Sized {}
#[lang = "unsize"]
pub trait Unsize<T> {}
#[lang = "coerce_unsized"]
pub trait CoerceUnsized<T> {}
impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
trait Foo<T, U> {}
trait Bar<U, T, X>: Foo<T, U> {}
trait Baz<T, X>: Bar<usize, T, X> {}
struct S<T, X>;
impl<T, X> Foo<T, usize> for S<T, X> {}
impl<T, X> Bar<usize, T, X> for S<T, X> {}
impl<T, X> Baz<T, X> for S<T, X> {}
fn test() {
let obj: &dyn Baz<i8, i16> = &S;
let obj: &dyn Bar<_, i8, i16> = &S;
let obj: &dyn Foo<i8, _> = &S;
}
"#, true),
@r###"
424..539 '{ ... &S; }': ()
434..437 'obj': &dyn Baz<i8, i16>
459..461 '&S': &S<i8, i16>
460..461 'S': S<i8, i16>
471..474 'obj': &dyn Bar<usize, i8, i16>
499..501 '&S': &S<i8, i16>
500..501 'S': S<i8, i16>
511..514 'obj': &dyn Foo<i8, usize>
534..536 '&S': &S<i8, {unknown}>
535..536 'S': S<i8, {unknown}>
"###
);
}
#[test]
// The rust reference says this should be possible, but rustc doesn't implement
// it. We used to support it, but Chalk doesn't.
#[ignore]
fn coerce_unsize_trait_object_to_trait_object() {
assert_snapshot!(
infer_with_mismatches(r#"
#[lang = "sized"]
@ -735,16 +781,17 @@ impl D for S {}
fn test() {
let obj: &dyn D = &S;
let obj: &dyn A = obj;
let obj: &dyn A = &S;
}
"#, true),
@r###"
328..384 '{ ...obj; }': ()
328..383 '{ ... &S; }': ()
338..341 'obj': &dyn D
352..354 '&S': &S
353..354 'S': S
364..367 'obj': &dyn A
378..381 'obj': &dyn D
378..380 '&S': &S
379..380 'S': S
"###
);
}